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commit 29f6d05875
575 changed files with 10909 additions and 42163 deletions

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@ -205,6 +205,9 @@ effectiveness of your controller.
%------------------------------------------------------------------------
% $Log$
% Revision 1.1 1999/04/05 21:32:34 curt
% Initial revision
%
% Revision 1.1 1999/03/09 19:09:41 curt
% Initial revision.
%

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@ -102,6 +102,9 @@ built this system, feel free to e-mail me at
%------------------------------------------------------------------------
% $Log$
% Revision 1.1 1999/04/05 21:32:34 curt
% Initial revision
%
% Revision 1.1 1999/03/09 19:09:41 curt
% Initial revision.
%

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# The "checkoutlist" file is used to support additional version controlled
# administrative files in $CVSROOT/CVSROOT, such as template files.
#
# The first entry on a line is a filename which will be checked out from
# the corresponding RCS file in the $CVSROOT/CVSROOT directory.
# The remainder of the line is an error message to use if the file cannot
# be checked out.
#
# File format:
#
# [<whitespace>]<filename><whitespace><error message><end-of-line>
#
# comment lines begin with '#'

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# The "commitinfo" file is used to control pre-commit checks.
# The filter on the right is invoked with the repository and a list
# of files to check. A non-zero exit of the filter program will
# cause the commit to be aborted.
#
# The first entry on a line is a regular expression which is tested
# against the directory that the change is being committed to, relative
# to the $CVSROOT. For the first match that is found, then the remainder
# of the line is the name of the filter to run.
#
# If the repository name does not match any of the regular expressions in this
# file, the "DEFAULT" line is used, if it is specified.
#
# If the name "ALL" appears as a regular expression it is always used
# in addition to the first matching regex or "DEFAULT".

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# Set this to "no" if pserver shouldn't check system users/passwords
#SystemAuth=no
# Set `PreservePermissions' to `yes' to save file status information
# in the repository.
#PreservePermissions=no

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# This file affects handling of files based on their names.
#
# The -t/-f options allow one to treat directories of files
# as a single file, or to transform a file in other ways on
# its way in and out of CVS.
#
# The -m option specifies whether CVS attempts to merge files.
#
# The -k option specifies keyword expansion (e.g. -kb for binary).
#
# Format of wrapper file ($CVSROOT/CVSROOT/cvswrappers or .cvswrappers)
#
# wildcard [option value][option value]...
#
# where option is one of
# -f from cvs filter value: path to filter
# -t to cvs filter value: path to filter
# -m update methodology value: MERGE or COPY
# -k expansion mode value: b, o, kkv, &c
#
# and value is a single-quote delimited value.
# For example:
#*.gif -k 'b'

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# The "editinfo" file is used to allow verification of logging
# information. It works best when a template (as specified in the
# rcsinfo file) is provided for the logging procedure. Given a
# template with locations for, a bug-id number, a list of people who
# reviewed the code before it can be checked in, and an external
# process to catalog the differences that were code reviewed, the
# following test can be applied to the code:
#
# Making sure that the entered bug-id number is correct.
# Validating that the code that was reviewed is indeed the code being
# checked in (using the bug-id number or a seperate review
# number to identify this particular code set.).
#
# If any of the above test failed, then the commit would be aborted.
#
# Actions such as mailing a copy of the report to each reviewer are
# better handled by an entry in the loginfo file.
#
# One thing that should be noted is the the ALL keyword is not
# supported. There can be only one entry that matches a given
# repository.

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# The "loginfo" file controls where "cvs commit" log information
# is sent. The first entry on a line is a regular expression which must match
# the directory that the change is being made to, relative to the
# $CVSROOT. If a match is found, then the remainder of the line is a filter
# program that should expect log information on its standard input.
#
# If the repository name does not match any of the regular expressions in this
# file, the "DEFAULT" line is used, if it is specified.
#
# If the name ALL appears as a regular expression it is always used
# in addition to the first matching regex or DEFAULT.
#
# You may specify a format string as part of the
# filter. The string is composed of a `%' followed
# by a single format character, or followed by a set of format
# characters surrounded by `{' and `}' as separators. The format
# characters are:
#
# s = file name
# V = old version number (pre-checkin)
# v = new version number (post-checkin)
#
# For example:
#DEFAULT (echo ""; id; echo %s; date; cat) >> $CVSROOT/CVSROOT/commitlog
# or
#DEFAULT (echo ""; id; echo %{sVv}; date; cat) >> $CVSROOT/CVSROOT/commitlog

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# Three different line formats are valid:
# key -a aliases...
# key [options] directory
# key [options] directory files...
#
# Where "options" are composed of:
# -i prog Run "prog" on "cvs commit" from top-level of module.
# -o prog Run "prog" on "cvs checkout" of module.
# -e prog Run "prog" on "cvs export" of module.
# -t prog Run "prog" on "cvs rtag" of module.
# -u prog Run "prog" on "cvs update" of module.
# -d dir Place module in directory "dir" instead of module name.
# -l Top-level directory only -- do not recurse.
#
# NOTE: If you change any of the "Run" options above, you'll have to
# release and re-checkout any working directories of these modules.
#
# And "directory" is a path to a directory relative to $CVSROOT.
#
# The "-a" option specifies an alias. An alias is interpreted as if
# everything on the right of the "-a" had been typed on the command line.
#
# You can encode a module within a module by using the special '&'
# character to interpose another module into the current module. This
# can be useful for creating a module that consists of many directories
# spread out over the entire source repository.

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@ -1,12 +0,0 @@
# The "notify" file controls where notifications from watches set by
# "cvs watch add" or "cvs edit" are sent. The first entry on a line is
# a regular expression which is tested against the directory that the
# change is being made to, relative to the $CVSROOT. If it matches,
# then the remainder of the line is a filter program that should contain
# one occurrence of %s for the user to notify, and information on its
# standard input.
#
# "ALL" or "DEFAULT" can be used in place of the regular expression.
#
# For example:
#ALL mail %s -s "CVS notification"

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@ -1,13 +0,0 @@
# The "rcsinfo" file is used to control templates with which the editor
# is invoked on commit and import.
#
# The first entry on a line is a regular expression which is tested
# against the directory that the change is being made to, relative to the
# $CVSROOT. For the first match that is found, then the remainder of the
# line is the name of the file that contains the template.
#
# If the repository name does not match any of the regular expressions in this
# file, the "DEFAULT" line is used, if it is specified.
#
# If the name "ALL" appears as a regular expression it is always used
# in addition to the first matching regex or "DEFAULT".

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@ -1,20 +0,0 @@
# The "taginfo" file is used to control pre-tag checks.
# The filter on the right is invoked with the following arguments:
#
# $1 -- tagname
# $2 -- operation "add" for tag, "mov" for tag -F, and "del" for tag -d
# $3 -- repository
# $4-> file revision [file revision ...]
#
# A non-zero exit of the filter program will cause the tag to be aborted.
#
# The first entry on a line is a regular expression which is tested
# against the directory that the change is being committed to, relative
# to the $CVSROOT. For the first match that is found, then the remainder
# of the line is the name of the filter to run.
#
# If the repository name does not match any of the regular expressions in this
# file, the "DEFAULT" line is used, if it is specified.
#
# If the name "ALL" appears as a regular expression it is always used
# in addition to the first matching regex or "DEFAULT".

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@ -1,21 +0,0 @@
# The "verifymsg" file is used to allow verification of logging
# information. It works best when a template (as specified in the
# rcsinfo file) is provided for the logging procedure. Given a
# template with locations for, a bug-id number, a list of people who
# reviewed the code before it can be checked in, and an external
# process to catalog the differences that were code reviewed, the
# following test can be applied to the code:
#
# Making sure that the entered bug-id number is correct.
# Validating that the code that was reviewed is indeed the code being
# checked in (using the bug-id number or a seperate review
# number to identify this particular code set.).
#
# If any of the above test failed, then the commit would be aborted.
#
# Actions such as mailing a copy of the report to each reviewer are
# better handled by an entry in the loginfo file.
#
# One thing that should be noted is the the ALL keyword is not
# supported. There can be only one entry that matches a given
# repository.

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@ -1,27 +0,0 @@
#FIG 3.2
Landscape
Center
Inches
Letter
100.00
Single
0
1200 2
5 1 0 1 0 7 0 0 -1 0.000 0 1 0 0 8962.500 6000.000 3600 5100 3525 6000 3600 6900
5 1 0 1 0 7 0 0 -1 0.000 0 1 0 0 10762.500 6000.000 5400 5100 5325 6000 5400 6900
5 1 0 1 0 7 0 0 -1 0.000 0 1 0 0 4500.000 -262.500 3600 5100 4500 5175 5400 5100
5 1 0 1 0 7 0 0 -1 0.000 0 0 0 0 4500.000 1537.500 5400 6900 4500 6975 3600 6900
5 1 2 1 0 7 0 0 -1 3.000 0 1 0 0 9825.000 6075.000 4500 5175 4425 6000 4500 6975
5 1 2 1 0 7 0 0 -1 3.000 0 0 0 0 4425.000 637.500 5325 6000 4425 6075 3525 6000
2 1 0 1 0 7 0 0 -1 0.000 0 0 -1 1 0 2
2 1 1.00 60.00 120.00
6000 5175 4425 6075
2 1 0 1 0 7 0 0 -1 0.000 0 0 -1 1 0 2
2 1 1.00 60.00 120.00
6000 5175 8550 5175
2 1 0 1 0 7 0 0 -1 0.000 0 0 -1 1 0 2
2 1 1.00 60.00 120.00
6000 5175 6000 2625
4 0 0 0 0 0 18 0.0000 4 195 180 8475 5475 X\001
4 0 0 0 0 0 18 0.0000 4 195 180 5700 2700 Y\001
4 0 0 0 0 0 18 0.0000 4 195 180 4500 5850 Z\001

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14
Docs/Misc/Features Normal file
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@ -0,0 +1,14 @@
Sky
stars
correct placement for time, date, and viewer position
correct magnitude
sun
correct position
lights the scene correctly
sky
blends into haze at horizon
sunset/sunrise effects
planets
correct position
correct magnitude

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@ -0,0 +1,142 @@
%% This LaTeX-file was created by <root> Sat Dec 5 17:56:02 1998
%% LyX 0.12 (C) 1995-1998 by Matthias Ettrich and the LyX Team
%% Do not edit this file unless you know what you are doing.
\documentclass{article}
\usepackage[T1]{fontenc}
\makeatletter
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% LyX specific LaTeX commands.
\newcommand{\LyX}{L\kern-.1667em\lower.25em\hbox{Y}\kern-.125emX\spacefactor1000}
\makeatother
\begin{document}
\vfill{}
\title{\emph{FlightGear} Flight Simulator\\
Portability Guide}
\vfill{}
\author{Bernie Bright (bbright@c031.aone.net.au)}
\date{28 November 1998}
\maketitle
FlightGear is a multi-platform general aviation flight simulator\@. It is an
open development project in which anyone with network access and a C++ compiler
can contribute patches or new features.\\
\section{Introduction}
The file \emph{Include/compiler.h} attempts to capture the differences between
C++ compiler and STL implementations through the use of ``feature test macros''\@.
The file is divided into two parts. The first part contains a section for each
compiler, consisting of manifest constants specifying the features supported
or absent from the particular compiler/STL combination\@. The second part uses
the feature test macros to supply any missing features\@.
\subsection{Supported compilers (more to come)}
gcc 2.7.x\\
gcc 2.8.x\\
egcs 1.x\\
Inprise (Borland) C++ 5.02\\
Inprise (Borland) C++Builder 1 (5.20)
\subsection{Features Tests}
\subsubsection{STL}
\begin{description}
\item [FG\_NEED\_AUTO\_PTR]Some STL implementations don't supply an \texttt{auto\_ptr<>}
class template. Define this to provide one.
\item [FG\_NO\_DEFAULT\_TEMPLATE\_ARGS]Define this if the compiler doesn't support
default arguments in template declarations. \emph{(example)}
\item [FG\_INCOMPLETE\_FUNCTIONAL]Some STL implementations don't have \texttt{mem\_fun\_ref()}.
Define this to provide one.
\item [FG\_NO\_ARROW\_OPERATOR]Define this if iterators don't support \texttt{operator->()}.
\emph{(example)}
\item [FG\_EXPLICIT\_FUNCTION\_TMPL\_ARGS]~
\item [FG\_MEMBER\_TEMPLATES]~
\end{description}
\subsubsection{Compiler}
\begin{description}
\item [FG\_NAMESPACES]Define if compiler supports namespaces.
\item [FG\_HAVE\_STD]Define if std:: namespace supported.
\item [FG\_HAVE\_STD\_INCLUDES]Define if headers should be included as \texttt{<iostream>}
instead of \texttt{<iostream}.h>. Also implies that all ISO C++ standard include
files are present.
\item [FG\_HAVE\_STREAMBUF]Define if \texttt{<streambuf>} or \texttt{<streambuf}.h>
are present.
\item [FG\_CLASS\_PARTIAL\_SPECIALIZATION]~
\item [FG\_NEED\_EXPLICIT]Define if the compiler doesn't support the \texttt{\textbf{explicit}}
keyword.
\item [FG\_NEED\_TYPENAME]Define if the compiler doesn't support the \texttt{\textbf{typename}}
keyword.
\item [FG\_NEED\_MUTABLE]Define if the compiler doesn't support the \texttt{\textbf{mutable}}
keyword.
\item [FG\_NEED\_BOOL]Define if the compiler doesn't have the \texttt{\textbf{bool}}
type.
\end{description}
\subsubsection{Include Files}
This section deals with header file naming conventions. Some systems truncate
filenames, 8.3 being common, other systems use old or non-standard names for
some header files. We deal with the simple cases by defining macros that expand
to the appropriate filename.
\begin{description}
\item [STD\_ALGORITHM]=> <algorithm>, ``algorithm''
\item [STD\_FUNCTIONAL]=> <functional>, ``functional''
\item [STD\_IOMANIP]=> <iomanip>, <iomanip.h>
\item [STD\_IOSTREAM]=> <iostream>, <iostream.h>, <iostreams.h>
\item [STD\_STDEXCEPT]=> <stdexcept> (ignore this, FlightGear doesn't use exceptions)
\item [STD\_STRING]=> <string>
\item [STD\_STRSTREAM]=> <strstream>, <strstream.h>
\end{description}
In use, instead of writing \#include <iostream> you write \#include STD\_IOSTREAM.\\
\\
The situation becomes complicated with missing header files. <streambuf> is
a good example. In this case we must rely on FG\_HAVE\_STD\_INCLUDES and FG\_HAVE\_STREAMBUF.\\
\emph{}\\
\emph{TODO}
\subsection{and the rest}
\subsubsection{Namespace Issues}
\begin{description}
\item [FG\_USING\_STD(X)]~
\item [FG\_NAMESPACE(X)]~
\item [FG\_NAMESPACE\_END]~
\item [FG\_USING\_NAMESPACE(X)]~
\end{description}
\subsubsection{Templates}
\begin{description}
\item [FG\_NULL\_TMPL\_ARGS]~
\item [FG\_TEMPLATE\_NULL]~
\end{description}
\begin{thebibliography}{}
\bibitem{1}Stroustrup, Bjarne, \emph{The C++ Programming Programming Language}, 3rd edition,
June 1997, ISBN 0-201-88954-4
\bibitem{2}SGI Standard Template Library (STL) release 3.11
\end{thebibliography}
\end{document}

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@ -202,6 +202,9 @@ so that you can never fly any closer to them.
%------------------------------------------------------------------------
% $Log$
% Revision 1.1 1999/04/05 21:32:34 curt
% Initial revision
%
% Revision 1.1 1999/02/14 19:10:47 curt
% Initial revisions.
%

3
Docs/Scenery/DEM.info Normal file
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@ -0,0 +1,3 @@
An online guide for interpreting the DEM data file format is available at:
http://edcwww.cr.usgs.gov/glis/hyper/guide/1_dgr_dem

Binary file not shown.

BIN
Docs/Scenery/DLG/dug-2.wp6.gz Executable file

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3013
Docs/Scenery/OBJ.format.txt Normal file

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@ -549,6 +549,9 @@ Generates the width of a 1/8 x 1/8 degree tile at various latitudes.
%------------------------------------------------------------------------
% $Log$
% Revision 1.1 1999/04/05 21:32:34 curt
% Initial revision
%
% Revision 1.4 1999/03/21 15:12:51 curt
% Updated to reflect current scenery progress.
%

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@ -0,0 +1,50 @@
Basically what I'm doing is starting with the 3 arcsec DEM files (a
point every 100 meters roughly.)
I start out at one corner and walk down a horizonal row. I start with
the first 2 points and do a least squares fit, I then add the next
point, and the next, and the next until my least squares fit exceeds
some error tolerance from the original data. At that point, I back up
one point and include that point in the output set of points. This
point then becomes my new starting point for the least squares fit. I
repeat this until I finish the row. I do this for each row to produce
an "irregular" set of output points from the original. I'm sure from
a pure mathematical perspective you can see some potential flaws in
this approach, but the actual real life result is actually quite good.
I then do a Delauney triangulation of these points (and add in more to
keep the triangles from getting too long and skinny.)
I have to go through additional pain to make sure that all the points
coincide on the edge between two adjacent areas (and the normals to so
there is continuity in the shading.)
I then run a "tri-striper" program to connect up all the individual
triangles into more efficient opengl strips.
Finally I post process everything to compensate for bugs in our lousy
tri-striper and to add in a few other things that our render requires.
There is a wee bit of documentation at:
http://www.menet.umn.edu/~curt/fgfs/Docs/Scenery/CoordinateSystem/CoordinateSystem.html
Here I lay out our basic coordinate system. Essentially the scenery
tiles that result in the above process are just cutouts of the Earths
surface. The maintain the curved shape and spacial orientation. The
renderer translates everything to near (0,0,0) to compensate for
GLfloat precision limitations.
All the tools I use to do this are distributed with the FG source, so
feel free to download them, play around, and ask questions.
Our resulting scenery tile format is structured to facilitate view
frustum culling on a per tile basis as well as a per "fragment" basis.
The next thing I plan to work on is sorting by material properties.
As I walk through the tile structures doing my view frustum culling,
instead of immediately rendering the visible fragments, I plan to toss
them into buckets by material property. Then I make a pass through
each of these buckets, rendering all the items with like properties.
This should minimize opengl state and texture changes which should
help keep the performance from going in the dumpster.

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@ -223,6 +223,9 @@ determine the proper angle for the sky dome rotation.
%------------------------------------------------------------------------
% $Log$
% Revision 1.1 1999/04/05 21:32:34 curt
% Initial revision
%
% Revision 1.1 1999/02/14 19:12:21 curt
% Initial revisions.
%

152
Docs/Time/Events/Events.tex Normal file
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%
% `Events.tex' -- describes the FG Event Manager
%
% Written by Curtis Olson. Started December, 1997.
%
% $Id$
%------------------------------------------------------------------------
\documentclass[12pt]{article}
\usepackage{anysize}
\papersize{11in}{8.5in}
\marginsize{1in}{1in}{1in}{1in}
\usepackage{amsmath}
\usepackage{epsfig}
\usepackage{setspace}
\onehalfspacing
\usepackage{url}
\begin{document}
\title{
Flight Gear Periodic Event Manager and Scheduler
}
\author{
Curtis L. Olson\\
(\texttt{curt@me.umn.edu})
}
\maketitle
\section{Introduction}
Many tasks within the simulator need to only run periodically. These
are typically tasks that calculate values that don't change
significantly in 1/60th of a second, but instead change noticeably on
the order of seconds, minutes, or hours.
Running these tasks every iteration would needless degrade
performance. Instead, we would like to spread these out over time to
minimize the impact they might have on frame rates, and minimize the
chance of pauses and hesitations.
\section{Overview}
The goal of the event manager is to provide a way for events to be run
periodically, and to spread this load out so that the processing time
spent at any particular iteration is minimized.
The scheduler consists of two parts. The first part is simply a list
of registered events along with any management information associated
with that event. The second part is a run queue. When events are
triggered, they are placed in the run queue. The system executes only
one pending event per iteration in order to balance the load.
\section{The Events List}
\subsection{Event List Structure}
All registered events are maintained in a list. Currently, this list
is simply an array of event structures. Each event structure stores
the following information.
\begin{itemize}
\item An ASCII description or event identifier. This is used when
outputting event statistics.
\item A pointer to the event function.
\item An event status flag. The flag marks the process as ready to
run, queued in the run queue, or suspended from eligibility to
run.
\item A time interval specifying how often to schedule and run this
event.
\item The absolute time this event was last run.
\item The next absolute time this event is scheduled to run.
\item The cumulative run time for this process (in ms.)
\item The least time consumed by a single run of this event (in ms.)
\item The most time consumed by a single run of this event (in ms.)
\item The number of times this event has been run.
\end{itemize}
\subsection{Event List Operation}
To use the event list, you must first initialize it by calling
\texttt{fgEventInit()}.
Once the list has been initialized, you can register events by calling
\texttt{fgEventRegister()}. A typical usage might be:
\texttt{fgEventRegister(``fgUpdateWeather()'', fgUpdateWeather,
FG\_EVENT\_READY, 60000)}. This tells the event manager to schedule
and run the event, \texttt{fgUpdateWeather()}, every 60 seconds. The
first field is an ASCII description of the function, the second field
is a pointer to the function, the third field is the status flag, and
the last field is the time interval. Event functions should return
\texttt{void} and accept no parameters. The status flag can set to
either \texttt{FG\_EVENT\_SUSP}, \texttt{FG\_EVENT\_READY}, or
\texttt{FG\_EVENT\_QUEUED}. \texttt{FG\_EVENT\_SUSP} means register
the event, but never schedule it to run. \texttt{FG\_EVENT\_READY}
means register the event and schedule and run it normally.
\texttt{FG\_EVENT\_QUEUED} is mostly used internally so that an event
will never have more than one entry in the run queue.
Finally, in your main loop, you must add a call to
\texttt{fgEventProcess()} to run it every iteration. This routine
will schedule all pending events (push them onto the run queue) and
then execute the first thing in the run queue.
\section{The Run Queue}
The run queue is a very simple queue who's elements are just a pointer
to an event list element. When an event needs to be scheduled, a
pointer to that event is pushed onto the back of the queue. Each time
\texttt{fgEventProcess()} is called, the first element on the run
queue will be executed.
\section{Profiling Events}
As stated before, each event record contains simple event statistics
such as the total time spent running this event, the quickest run, the
slowest run, and the total number of times run. We can output the
list of events along with these statistics in order to determine if any of
them are consuming an excessive amount of time, or if there is any
chance that a particular event could run slow enough to be responsible
for a perceived hesitation or pause in the flow of the simulation.
\end{document}
%------------------------------------------------------------------------
% $Log$
% Revision 1.1 1999/04/05 21:32:34 curt
% Initial revision
%

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Hints/aaa Normal file
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Subject: Re: culling with view frustrum before view transformation
Date: Wed, 20 Aug 1997 14:14:39 -0800
> >Brian Hook wrote:
> >> You can do bounding spheres,
> >> bounding boxes, or a combination of both (sphere first, then box).
> >
> >Which is faster to test for being completely inside, outside, or
> >partial, of the view frustrum?
>
> Obviously bounding sphere will be the fastest, but since it's, well, a
> sphere, it's not going to be particularly accurate (since it's rotationally
> invariant).
>
> if ( distance( obj.position, plane ) >= obj_sphere.radius )
> trivial_reject = true;
>
> (I assume you also check the sign of the distance)
I echo your sentiments that bounding spheres are the fastest approach to
culling to FOV frustum - also for some kinds of collision detection.
The most important thing to bear in mind about culling is that the first
trivial-reject test you apply is by far the most time-critical. This test
is always applied to more nodes than any of the subsequent tests.
So, do the cheapest test first.
This is typically the NEAR plane test. Everything behind the viewers head
gets chopped out - and it's an especially cheap test.
if ( obj_sphere.center.z < near_plane - obj_sphere.radius )
REJECT!!
...next do the second cheapest test (assuming you know that your database
could possibly beyond the far clip plane)...
if ( obj_sphere.center.z - obj_sphere.radius > far_plane )
REJECT!!
...and *then* do...
if ( distance( obj.position, plane ) >= obj_sphere.radius )
REJECT!!
It's also useful to know that in many applications, you cull more objects from
the left and right faces of the frustum than you do from the top and bottom - so
test left, then right, then bottom then top.
Also, with bounding sphere tests, you shouldn't forget to do total-accept
as well as total-reject tests. Once you know that an object's sphere is
TOTALLY on screen, you don't have to descend into the daughter objects to
cull-test them...you *know* they are all on-screen.
Another way to look at that it to remember which of the six possible plane tests
didn't even touch the sphere - as you work your way down the object hierarchy,
you can accumulate those flags and avoid even testing those planes that a parent
sphere has already cleanly passed. If you do this then a vast percentage of
your spheres will only need to be tested against one plane.
Sphere-based culling can be extremely cost-effective. It's so cheap that even if
you feel the need to use a bounding cubeoid (or even a yet more complex shape),
it's still worth doing a sphere-based cull first just to get rid of the trivial
accept and reject cases.
Steve Baker 817-619-1361 (Vox-Lab)
Hughes Training Inc. 817-619-8776 (Vox-Office/Vox-Mail)
2200 Arlington Downs Road 817-619-4028 (Fax)
Arlington, Texas. TX 76005-6171 Steve@MrEd.bgm.link.com (eMail)
http://www.hti.com http://web2.airmail.net/sjbaker1 (personal)
** Beware of Geeks bearing GIF's. **
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Subject: Re: culling with view FRUSTUM before view transformation
Date: Thu, 21 Aug 1997 07:00:54 -0800
> OK, this is probably explained in books etc., but what is the fastest way
> to find the distance between a point and a plane?
A plane can be represented by the equation
Ax + By + Cz + D = 0 ;
A,B,C is just the surface normal of the plane and D is the shortest
distance from the origin to the plane.
So, if you need to find the distance of a point from the plane, just
imagine a new plane that goes through your test point and is parallel
to the plane you want to test. The plane equation of that new plane would be:
A'x + B'y + C'z + D' = 0 ;
Since the two planes are parallel, their surface normals are the same, so
A' == A
B' == B
C' == C
D' == D + distance_between_the_two_planes
...the only thing that's different is their D values - which differ by the
distance of your test point from the original plane.
So, for a point (x,y,z), the distance from the plane (A,B,C,D) is
dist = D' - D
= -A'x - B'y - C'z - D
= -Ax - By - Cz - D
= -( [ABC]dot[xyz] + D )
That's the general result - but culling to the view frustum is a very
special case...if you are working in eye-relative coordinates (IMHO this
is best), then since all top,bot,left,right planes of the frustum meet
at the eye - and since the eye is at the origin (by definition), then
D is always zero for those plane and that saves you a subtract.
If you are feeling even more in need of optimisation - then you can save one
multiply per plane by realising that (for rectangular screens) one of the
three components of the plane equation will always be zero.
eg for the LEFT clip plane, the Y component of the normal of the plane
is zero, so the distance to the left or right plane is just
- ( A x' + C z' )
and to the top or bottom plane it's just:
- ( A x' + B y' )
Since you are only using this for culling, you don't need the minus sign
so the cost of a test can be as little as two multiplies and one add
per plane.
Steve Baker 817-619-1361 (Vox-Lab)
Hughes Training Inc. 817-619-8776 (Vox-Office/Vox-Mail)
2200 Arlington Downs Road 817-619-4028 (Fax)
Arlington, Texas. TX 76005-6171 Steve@MrEd.bgm.link.com (eMail)
http://www.hti.com http://web2.airmail.net/sjbaker1 (personal)
** Beware of Geeks bearing GIF's. **
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Subject: Re: culling with view FRUSTUM before view transformation
Date: Fri, 22 Aug 1997 06:31:24 -0800
> > > Actually, I find it easier to scale the whole such that D = 1, then you
> > > only need to store the non-degenerate (A', B', C') vector (i.e., A' =
> > > A/D, etc...). Storing a already-normalized (A, B, C) + D quadruple is
> > > worth it only if you know before hand that the planes will never be
> > > scaled before their normals are used. In the general case where a
> > > scaling is possible, you'll have to renormalize anyway.
> >
> > Normally, I might agree with you - but in the case of Frustum clipping,
> > scaling the normal by dividing by 'D' is a bad move since D==0 in the
> > case of all four 'interesting' planes. :-)
>
> Interesting point. This is of course only true when the eyepoint is in
> the origin, which brings us back to the issue of clipping before or
> after the modelview transformation.
Well - that's a dangerous thing to assume - I mean, the eye might just happen
to move to the true world coordinate origin (by flook) and crash your program
with a bunch of divide by zero errors.
In any case, you are going to run into nasty precision problems as your eye
approaches the origin - even if it doesn't reach it.
> Learn something new every day.... :-)
...Forget something important every night... :-)
Steve Baker 817-619-1361 (Vox-Lab)
Hughes Training Inc. 817-619-8776 (Vox-Office/Vox-Mail)
2200 Arlington Downs Road 817-619-4028 (Fax)
Arlington, Texas. TX 76005-6171 Steve@MrEd.bgm.link.com (eMail)
http://www.hti.com http://web2.airmail.net/sjbaker1 (personal)
** Beware of Geeks bearing GIF's. **
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Subject: Re: Endian swapping
Date: Fri, 15 May 1998 06:30:53 -0800
On Fri, 15 May 1998, Sean L. Palmer wrote:
> I'm trying to make this library as cross-platform as humanly possible with
> my limited resources, so if anyone has any code to detect whether the target
> is Big- or Little-endian, please e-mail it my way.
/*
Return TRUE if this machine is little endian,
FALSE otherwise.
*/
int is_little_endian ()
{
int i = 1 ;
return *((char *) &i) ;
}
...this works because the address of an integer on a little-endian machine is
the address of the low order byte (whose value is 1) and on a big-endian machine,
it's the address of the high order byte (whose value is 0).
Steve Baker (817)619-8776 (Vox/Vox-Mail)
Raytheon Systems Inc. (817)619-4028 (Fax)
Work: SBaker@link.com http://www.hti.com
Home: SJBaker1@airmail.net http://web2.airmail.net/sjbaker1
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From owner-flight-gear@me.umn.edu Thu Apr 23 08:45:16 1998
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To: flight-gear@me.umn.edu
Subject: Re: [FGFS] lighting question
Date: Thu, 23 Apr 1998 09:44:56 -0500 (CDT)
On Wed, 22 Apr 1998, Curtis L. Olson wrote:
> Here's a lighting question for someone.
>
> Let's say it's noon-ish. If I set the ambient light component to
> about 0.3 and the diffuse light component to about 1.0 I get a
> reasonably bright scene with good contrast in the shadowy areas.
>
> Now, I'm running into problems when the sun is low in the sky. Even
> with a high diffuse lighting component (1.0) the angle the sun light
> makes with the horizontal ground is very small so the diffuse lighting
> component ends up being virtually nothing. I'm fiddling around with
> trying to increase the ambient component to 1.0, but I still get a
> very dark scene.
...simple question - long answer - sorry...
First the "Why does this look bad?" answer...
Well, when the sun is low in the sky, that is exactly what really
does happen - the angle between sun and (flattish) ground gets small
and it gets dark.
The problem is that our eyes have automatic gain control. When the
world gets darker, we increase our pupil apartures to increase the
amount of light we allow in. That only works when the whole world
goes darker - and not in a room in normal daylight containing a
small, dim CRT.
Also, in the real world, the sun lights things much more brightly
than a CRT phosphor can reproduce. When you drop that brightness
by (say) a factor of ten because it's dusk then the sun is still
pretty bright - but 1/10th the brightness on a CRT phosphor is pretty
dim.
If you watch your sunset scenes in a darkened room, they'll look
much better. However, for a desktop simulation, that may not help.
The other reason there is a problem is that the CRT phosphor is
not a linear device - if you double the number for the pixel
brightness - you don't get twice the brightness coming out the
other side. This non-linearity is *supposed* to be corrected
by a process called 'gamma correction' which works by boosting
the contrast of the dark pixels and reducing the contrast of
the bright ones.
Fixing the gamma will help noon-time scenes as well as dusk
and dawn since the amount of stuff you can see in shadowed
areas will be better if the gamma is set right.
The required amount of gamma modification changes with the
age of the CRT and which particular choice of phosphor layer
the CRT manufacturer made. You may also need more gamma correction
in (say) the BLUE channel than in RED or GREEN.
Fancy machines like SGI ONYX's have hardware gamma tables on
the output of the machine to do this correction - I doubt that
all the PC-based 'toy' 3D cards have this feature.
Now, the "What can we do to improve matters?" answer...
Well, you seem to be on the right track - you basically have to increase
the ambient light to make up for the missing light on the horizontal
surfaces. However, this tends to reduce the amount of contrast between
the dark regions and the vertical surfaces that are being brightly lit
just as the sun goes down. That is the opposite of the real world since
the shadows are much more contrasty late in the day than they are at noon.
(That is a subjective thing - I could be wrong about that)
You said:
> I'm fiddling around with trying to increase the ambient component to 1.0,
> but I still get a very dark scene.
...that suprises me - you ought to be getting a very bright scene
with ambient==1.0 since all surfaces are being lit with a very bright
light that is ignoring their orientation. The scene should be brighter
than at noon.
Perhaps you don't have the ambient component of the glMaterial set
up right?
On the gamma front, there are two experiments you can try:
Curt: I know you have access to an SGI RE2 machine - and that
you can run FGFS on it. So, run FGFS up and set the time of
day to dusk - so you have the too-dark scene. Now open another
shell window and try running 'gamma 1.0' then 'gamma 1.5' then
'gamma 2.0'. If I'm right about the gamma setting being the problem
then gamma 1.0 should look just like it does on the PC, and
(depending on the age of your CRT), 1.5 or 2.0 (or something like
that) should make it look much better.
If you can't get to an SGI machine then do a screen dump of your
image into a file, then load that file into Xview (under Linux)
or something like photoshop. Image processing programs like this
usually let you change the gamma for an image interactively by
recomputing the pixels (this eliminates the need for gamma hardware).
In XView, pick the colour editor window and click on the gamma
button next to the intensity graph. Type in 2.0 (or whatever) and
you'll notice that the curve in the window looks like this:
****
**
*
*
*
*
*
*
*
(pardon the ASCII art)
....which means that the dark areas have been increased in contrast
and the light areas reduced in contrast.
If either of these tests shows that gamma is indeed your problem then
you need to think about how to set the gamma on your hardware.
For software OpenGL with Mesa - I think Mesa has a gamma setting
extension (or an environment variable or something) - the 3Dfx
card (IIRC) has a way to set the gamma too - although I don't
know how. The general way to set the gamma is not through OpenGL,
so doing this in a portable way from inside FGFS is going to be hard.
You may have to rely on the user setting it up in some external
tool (a windoze control panel most likely).
> I may have something fouled up, or may not understand something
> correctly, but does anyone have any suggestions as to what the ambient
> and diffuse lighting components ought to be set to in order for the
> scenery to be "realistically" lit when the sun is low in the sky?
Well, 'realistically' is a hard thing - the human eye can discern detail
in a scene lit at a gazillion candelas - all the way down to a gazillionth
of a candela, lots of orders of magnitude. A CRT can only display the
number of brightness levels provided in the frame buffer (256 if you are
lucky - a mere 2.5 orders of magnitude) - and is VERY dim in any case.
Getting 'realistic' brightnesses just isn't going to happen on a desktop
display system - so it's all a matter of compromise.
On 'real' flight simulators, the fight for better contrast and brightness
and more orders of magnitude of brightness variation is a continual battle
that results in some pretty exotic display technologies. (Things like
shining an arc-lamp onto a million tiny mirrors that are tilted using
pizo-electric effects to modulate the brightness...ugh!)
Steve Baker (817)619-8776 (Vox/Vox-Mail)
Raytheon Systems Inc. (817)619-4028 (Fax)
Work: SBaker@link.com http://www.hti.com
Home: SJBaker1@airmail.net http://web2.airmail.net/sjbaker1
-------------------------------------
Please visit the FGFS web page: http://www.menet.umn.edu/~curt/fgfs/
For help on using this list (especially unsubscribing), send a message to
"flight-gear-request@me.umn.edu" with a single line of text: "help".

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From owner-fgfs-devel@flightgear.org Mon Sep 14 10:44:02 1998
X-VM-v5-Data: ([nil nil nil nil nil nil nil nil nil]
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From: Steve Baker <sbaker@link.com>
Sender: owner-fgfs-devel@flightgear.org
To: William Riley <riley@technologist.com>
cc: fgfs-devel@flightgear.org
Subject: Re: FGFS: Windows Joystick support
Date: Mon, 14 Sep 1998 10:41:38 -0500 (CDT)
On Sun, 13 Sep 1998, William Riley wrote:
> Is anyone working on joystick support for Win9x/NT? I'm a fledgling
> programmer and was thinking about tacking this task. If anyone has started
> (or finished) please email me directly or through the list. Thanks.
There is basic joystick support in GLUT - I presume the simplest thing
to do to start with is to use that since the result will be portable to
all of our target systems.
The downside is that IIRC, GLUT only supports a very simple joystick
setup (single stick, two axes, two buttons).
Whatever API we finally choose needs to consider the portability issues.
IMHO, it would be better to extend GLUT and offer any improvements back
into the general Freeware community rather than to settle on an ad'hoc
FGFS-specific solution.
Joystick info for Linux can be found here:
http://atrey.karlin.mff.cuni.cz/~vojtech/joystick/
Joystick programming info for Windoze is here:
http://www.hut.fi/Misc/Electronics/docs/joystick/pc_joystick.html#programming
That same site has a TON of interesting joystick info:
http://www.hut.fi/Misc/Electronics/docs/joystick/
GLUT's joystick support is not documented yet since it's only present in the
very latest GLUT 3.7 beta. However, if you check the source code for that
release of GLUT, you'll see how it's done there.
Steve Baker (817)619-2657 (Vox/Vox-Mail)
Raytheon Systems Inc. (817)619-4028 (Fax)
Work: SBaker@link.com http://www.hti.com
Home: SJBaker1@airmail.net http://web2.airmail.net/sjbaker1

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From curt@infoplane.com Fri Nov 13 06:10:29 1998
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["6615" "Fri" "13" "November" "1998" "06:10:23" "-0600" "curt@infoplane.com" "curt@infoplane.com" nil "271" "fuzzy-light-effect" "^From:" nil nil "11" nil nil nil nil nil]
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From: curt@infoplane.com
To: curt@me.umn.edu
Subject: fuzzy-light-effect
Date: Fri, 13 Nov 1998 06:10:23 -0600
/* stars - draws a twisting sphere of eerie lights
Copyright (C) 1998 James Bowman
stars is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2, or (at your option)
any later version.
gpasm is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with gpasm; see the file COPYING. If not, write to
the Free Software Foundation, 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA. */
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <math.h> /* for cos(), sin(), and sqrt() */
#include <assert.h>
#ifdef WIN32
#include <time.h>
#else
#include <sys/time.h>
#endif
#include <GL/glut.h>
static int phi; /* Global clock */
static int texWidth = 64; /* 64x64 is plenty */
/************************************************************************/
/* Generate a pleasing, light-shaped texture. */
static void
setTexture(void)
{
int texSize;
void *textureBuf;
GLubyte *p;
int i,j;
double radius;
texSize = texWidth*texWidth;
textureBuf = malloc(texSize);
if (NULL == textureBuf) return;
p = (GLubyte *)textureBuf;
radius = (double)(texWidth / 2);
for (i=0; i < texWidth; i++) {
for (j=0; j < texWidth; j++) {
double x, y, d;
x = fabs((double)(i - (texWidth / 2)));
y = fabs((double)(j - (texWidth / 2)));
d = sqrt((x * x) + (y * y));
if (d < radius) {
double t = 1.0 - (d / radius); /* t is 1.0 at center,
0.0 at edge */
/* inverse square looks nice */
*p = (int)((double)0xff * (t * t));
} else
*p = 0x00;
p++;
}
}
gluBuild2DMipmaps(GL_TEXTURE_2D, 1, texWidth, texWidth,
GL_LUMINANCE,
GL_UNSIGNED_BYTE, textureBuf);
free(textureBuf);
}
/************************************************************************/
static int W, H;
#define NUM_STARS 100
#define frand() ((float)(rand() & 0xfff) / (float)0x1000) /* 0.0 - 1.0 */
#define frand2() (1.0f - (2.0f * frand())) /* -1 - +1 */
/* Normalise the input vector */
static void vecNormalise(float *vv)
{
double mag;
mag = sqrt((vv[0] * vv[0]) + (vv[1] * vv[1]) + (vv[2] * vv[2]));
vv[0] /= mag;
vv[1] /= mag;
vv[2] /= mag;
}
void
redraw_viewing(void)
{
static int cold = 1;
static float stars[NUM_STARS * 3];
GLfloat fb_buffer[NUM_STARS * 4];
int i;
if (cold) {
/* Position all the stars more-or-less randomly on the surface
* of a unit sphere. */
for (i = 0; i < NUM_STARS; i++) {
stars[3 * i + 0] = frand2();
stars[3 * i + 1] = frand2();
stars[3 * i + 2] = frand2();
vecNormalise(&stars[3 * i]);
}
cold = 0;
}
glClear(GL_COLOR_BUFFER_BIT);
/* First use feedback to determine the screen positions of the
stars. */
glFeedbackBuffer(NUM_STARS * 4, GL_3D, fb_buffer);
glRenderMode(GL_FEEDBACK);
glMatrixMode(GL_MODELVIEW);
glPushMatrix();
glRotatef(phi % 360, 0.0f, 1.0f, 0.0f); /* Constant spin */
glRotatef(sin((double)phi / 300.0) * 150.0, /* Periodic twist */
0.1f, 0.6f, -0.5f);
glBegin(GL_POINTS);
for (i = 0; i < NUM_STARS; i++)
glVertex3fv(&stars[3 * i]);
glEnd();
glPopMatrix();
glRenderMode(GL_RENDER); /* No more feedback */
/* Now draw the stars as sprites. */
glEnable(GL_TEXTURE_2D);
glEnable(GL_BLEND); /* Simple additive blend is fine */
glBlendFunc(GL_ONE, GL_ONE);
/* Choose a color triple like this so that when the sprites overlap
* and the color saturates, red will clamp first, then green, then
* blue. */
glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE);
glColor3f(1.0f, 0.75f, 0.5f);
/* Set up projection and modelview matrix that gives us a 1:1
* mapping to screen coordinates. */
glMatrixMode(GL_PROJECTION);
glPushMatrix();
glLoadIdentity();
glMatrixMode(GL_MODELVIEW);
glPushMatrix();
glLoadIdentity();
glScalef(2.0f / (GLfloat)W, 2.0f / (GLfloat)H, 1.0f);
glTranslatef(0.5f * -(GLfloat)W, 0.5f * -(GLfloat)H, 0.0f);
{
float width;
float x, y, z;
int i;
glBegin(GL_QUADS);
for (i = 0; i < NUM_STARS; i++) {
/* Skip the GL_POINT_TOKEN */
x = fb_buffer[4 * i + 1];
y = fb_buffer[4 * i + 2];
z = fb_buffer[4 * i + 3];
width = 10.0 * (2.0 - z); /* Arbitrary distance attenuation */
glTexCoord2f(0.0f, 0.0f);
glVertex2f(x - width, y - width);
glTexCoord2f(1.0f, 0.0f);
glVertex2f(x + width, y - width);
glTexCoord2f(1.0f, 1.0f);
glVertex2f(x + width, y + width);
glTexCoord2f(0.0f, 1.0f);
glVertex2f(x - width, y + width);
}
glEnd();
}
glMatrixMode(GL_MODELVIEW);
glPopMatrix();
glMatrixMode(GL_PROJECTION);
glPopMatrix();
glutSwapBuffers();
}
void
reshape_viewing(int w, int h)
{
glViewport(0, 0, w, h);
W = w;
H = h;
}
/************************************************************************/
void
animate(void)
{
phi++;
redraw_viewing();
}
void
key(unsigned char key, int x, int y)
{
switch (key) {
case 27:
case 'q':
exit(0);
}
}
int
main(int argc, char **argv)
{
glutInit(&argc, argv);
glutInitDisplayMode(GLUT_RGB | GLUT_DOUBLE);
glutInitWindowSize(640, 480);
glutCreateWindow("stars");
glutReshapeFunc(reshape_viewing);
glutDisplayFunc(redraw_viewing);
glutIdleFunc(animate);
glutKeyboardFunc(key);
glDisable(GL_DEPTH_TEST);
glDisable(GL_LIGHTING);
glMatrixMode(GL_MODELVIEW);
setTexture();
glTexParameteri(GL_TEXTURE_2D,
GL_TEXTURE_MIN_FILTER,
GL_LINEAR_MIPMAP_NEAREST);
glTexParameteri(GL_TEXTURE_2D,
GL_TEXTURE_MAG_FILTER,
GL_LINEAR);
glMatrixMode(GL_PROJECTION);
gluPerspective( /* field of view in degree */ 40.0f,
/* aspect ratio */ 1.0f,
/* Z near */ 3.0f,
/* Z far */ 5.0f);
glMatrixMode(GL_MODELVIEW);
gluLookAt(0.0f, 0.0f, 4.0f, /* eye position */
0.0f, 0.0f, 0.0f, /* looking at */
0.0f, 1.0f, 0.0f); /* up vector */
glutMainLoop();
return 0; /* ANSI C requires main to return int. */
}

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From sbaker@link.com Thu Mar 12 22:51:27 1998
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["4342" "Thu" "12" "March" "1998" "22:50:07" "-0600" "Steve Baker" "sbaker@link.com" "<Pine.SGI.3.96.980312222643.15355F-100000@lechter.bgm.link.com>" "95" "Re: Texturing (finally)" "^From:" nil nil "3" nil nil nil nil nil]
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Reply-To: Steve Baker <sbaker@link.com>
In-Reply-To: <199803121856.MAA05616@kenai.me.umn.edu>
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Status: RO
From: Steve Baker <sbaker@link.com>
To: "Curtis L. Olson" <curt@me.umn.edu>
Subject: Re: Texturing (finally)
Date: Thu, 12 Mar 1998 22:50:07 -0600 (CST)
On Thu, 12 Mar 1998, Curtis L. Olson wrote:
> Steve Baker writes:
> > So you have the texture into OpenGL using glGenTextures /
> > glBindTexture and you have a number for each texture? Does the
> > routine generate the MIPmaps for you?
>
> I found some code that looks like it might do the mipmapping ... I'll
> fiddle around with that a bit if I get a chance.
Once you have an image in memory, the code in the RedBook is all you need.
There is a glu function for generating the MIPmaps. It works OK for
starters - but eventually you'll want to rewrite it. Since the sources
for glu are provided with Mesa (and they work with ANY OpenGL), you
can easily take the standard glu code and hack it yourself later.
The main thing that I find I need to do with MIPmapping is to control
the final alpha value of MIPmapped transparency textures. Simply averaging
all the high level texel Alpha's together to get the lowest LOD doesn't
work very well in some applications for translucent texture.
However, that won't matter to you for a LONG while yet - so just steal
the RedBook examples.
> > As a starter (just to get something going), you could simply divide
> > the latitude and longitude of each terrain vertex by some suitable
> > constant and use that as the texture coordinate. Alternatively, you
> > could let OpenGL do the work using glTexGenf.
>
> Tell me more about glTexGenf().
I have to come clean here and mention that I have never actually used
glTexGenf.
Basically, it provides a mechanism where OpenGL will generate the
texture coordinates for you automatically using other vertex information.
I forget all the modes it has - but IIRC, one of them allows you to specify
the equation of a plane (A,B,C,D where: Ax+By+Cz+D==0) - and the texture
coordinates are computed by projecting each vertex (x,y,z) onto that
plane.
If you set that plane to be a plane that is tangential to the earth
at the center of the terrain tile that you are rendering, then the
texture would 'drape' itself nicely over the terrain - but there would
be seams at the edge of each tile.
> All my coordinates come off the disk
> in (X, Y, Z) so it would take some computational effort to convert
> back to lon/lat ...
Yes - you'd need to store (X,Y,Z,S,T) for each vertex on disk and compute
the texture coordinates in the terrain tool. You'd need to do that
eventually anyway since the number you use to multiply the lat/long
to convert to S,T will be different for each kind of texture map - and
for databases at different latitudes (otherwise the texture gets all
squashed up near the poles).
I guess if you don't want to change your file format that much, you
could store a matrix at the top of the file that could be used to
transform (X,Y,Z) into (S,T,garbage). But that's really the same
thing as using glTexGen to do the work - and you'll still get seams
at the edge of every terrain tile whenever the matrix changes.
Since OpenGL supports the idea of a texture matrix, you could simply
load your per-tile matrix onto the OpenGL texture matrix stack and
use glTexCoord3f(x,y,z) [where (x,y,z) is the same vertex coordinate
that you pass to glVertex3f()].
However, in your quest to DO THE RIGHT THING, there is little choice
but to store the texture S,T in the file along with the other vertex
information - any other approach is going to produce seams in the texture
and sooner or later, you'll get dissatisfied with that.
I suggest that in the short term, you use the texture matrix approach
since that gets you a textured image *quickly*. It will also let you
debug the texture loader, the MIPmapping, the glTexBind, etc stuff
and so on. You'll be able to find some nice textures and make some
new (and v.cool) screen shots. Switching to stored (S,T) coords is
something you can attack later when the seams get too annoying.
> Right now I'm using fg_random() to specify
> texture coordinates :-) It seems to work, but has some strange
> effects. :-)
Strange!!...I'm not suprised!
Steve Baker 817-619-8776 (Vox/Vox-Mail)
Raytheon Systems Inc. 817-619-4028 (Fax)
2200 Arlington Downs Road SBaker@link.com (eMail)
Arlington, Texas. TX 76005-6171 SJBaker1@airmail.net (Personal eMail)
http://www.hti.com http://web2.airmail.net/sjbaker1 (personal)
** Beware of Geeks bearing GIF's. **

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From curt@me.umn.edu Fri Nov 13 17:02:31 1998
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["209" "Fri" "13" "November" "1998" "17:02:29" "-0600" "Curtis L. Olson" "curt@me.umn.edu" nil "6" "nmea stuff 3" "^From:" nil nil "11" nil nil nil nil nil]
nil)
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From: "Curtis L. Olson" <curt@me.umn.edu>
To: curt@me.umn.edu
Subject: nmea stuff 3
Date: Fri, 13 Nov 1998 17:02:29 -0600 (CST)
http://www.marinesoft.com/Navigation/Technical/index.htm
--
Curtis Olson University of MN, ME Dept.
curt@me.umn.edu
http://www.menet.umn.edu/~curt Try Linux!
From curt@me.umn.edu Fri Nov 13 16:41:49 1998
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["730" "Fri" "13" "November" "1998" "16:41:47" "-0600" "Curtis L. Olson" "curt@me.umn.edu" nil "21" "nmea stuff 2" "^From:" nil nil "11" nil nil nil nil nil]
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From: "Curtis L. Olson" <curt@me.umn.edu>
To: curt@me.umn.edu
Subject: nmea stuff 2
Date: Fri, 13 Nov 1998 16:41:47 -0600 (CST)
http://www.fet.uni-hannover.de/~purnhage/gps/gps.html
garman hacking project
http://www.abnormal.com/~thogard/gps/grmnhack.html
nmea code documents
http://www.oce.orst.edu/Wecoma/Docs/Computing/XMidas/Formatter_ID.html
http://www.oce.orst.edu/Wecoma/Docs/Computing/XMidas/NMEA_0183_Format.html
http://www.cl.cam.ac.uk/users/ijl20/nmea.txt
http://www.cl.cam.ac.uk/users/ijl20/gps_file.html
(*) http://vancouver-webpages.com/pub/peter/index.html
http://vancouver-webpages.com/pub/peter/idx_nmeadoc.html
http://vancouver-webpages.com/pub/peter/nmeafaq.txt
--
Curtis Olson University of MN, ME Dept.
curt@me.umn.edu
http://www.menet.umn.edu/~curt Try Linux!
From curt@me.umn.edu Fri Nov 13 15:10:29 1998
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["376" "Fri" "13" "November" "1998" "15:10:27" "-0600" "Curtis L. Olson" "curt@me.umn.edu" nil "14" "nmea stuff" "^From:" nil nil "11" nil nil nil nil nil]
nil)
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From: "Curtis L. Olson" <curt@me.umn.edu>
To: curt@me.umn.edu
Subject: nmea stuff
Date: Fri, 13 Nov 1998 15:10:27 -0600 (CST)
http://pfranc.com/projects/g45contr/assemb.htm
http://pfranc.com/ - gps connector
http://pfranc.com/projects/g45contr/beans.htm
http://www.thecapn.com/
http://www.thecapn.com/nmea.htm
http://vancouver-webpages.com/peter/
--
Curtis Olson University of MN, ME Dept.
curt@me.umn.edu
http://www.menet.umn.edu/~curt Try Linux!

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Original Article: http://www.egroups.com/list/opengl-gamedev-l/?start=11533
Ben Carter writes:
>
> Hmm.. Here's a question - is it worth optimising out redundant state
> changes? In other words, if I do :
>
> glEnable(GL_TEXTURE_2D);
> <something>
> glEnable(GL_TEXTURE_2D);
> <something else>
Generally, yes. There's usually a validation step that's scheduled
after a call to glEnable(). It updates the internals caches and what
not based on state that was set prior to the enable call. Its difficult
to estimate what every driver does, but there's still internal updating
that probably occurs.
Additionally, its much better to write, for example:
glLightfv( GL_LIGHT0, ... );
glLightfv( GL_LIGHT0, ... );
glLightfv( GL_LIGHT0, ... );
glEnable( GL_LIGHT0 );
glEnable( GL_LIGHTING );
than the opposite. Its less important to do this in initialization, but
if you're dynamically changing things like lighting or texturing, you'll
only validate on the glEnable(), as compared to each glLight() call if
you glEnable() first.
> Is there going to be a performance hit from the second glEnable call?
> Would it be worthwhile writing a wrapper around the state system that
> kept the current state somewhere and only made calls that were
> necessary, or are the drivers smart enough to do that?
Some drivers might be smart enough, but I think the underlying
assumption is that its easier to just reprocess like something's
changed, than actually try to keep track of which state's changed, and
localize that validation.
The wrapper idea could be useful; I guess it depends if the apps
design can't guard against it. FWIW.
Thanx,
Dave
---------------------------------------------------------------------
Dave Shreiner <shreiner@sgi.com>
Silicon Graphics, Inc. (650) 933-4899
-----
FAQ and OpenGL Resources at:
http://www.geocities.com/SiliconValley/Hills/9956/OpenGL
--
Author: Dave Shreiner
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From fatcity!root@news.cts.com Thu Mar 26 17:57:48 1998
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Subject: Re: poly offset
Date: Thu, 26 Mar 1998 15:32:55 -0800
Bryan Gibson-Winge wrote:
| I was curious to see if anyone would describe a method of using poly offset
| that didn't eventually conclude with "and mess with the numbers 'till it
| works".
There is such a method, but since it's not in any of the usual OpenGL
literature it's not widely discussed. I'll try to summarize it; maybe
the result could go into the FAQ.
The purpose of polygon offset is to separate two or more primitives
by just enough distance in Z that they can be depth-buffered without
artifacts caused by depth computation roundoff errors, differences in
sampling algorithms for different types of primitives, etc.
The ``factor'' argument provides separation in the case where the
primitives are not parallel. The factor value to use depends on the
screen sizes of the primitives involved.
The canonical example is highlighting the edge of a triangle
by drawing a line between the two associated triangle vertices.
The depth value for each pixel on the line depends only on the
depth values at the two vertices of the triangle edge. However,
the depth value for each pixel in the triangle depends on all
three of the triangle's vertices. Since lines and triangles are
sampled differently (e.g. diamond-exit rule for lines vs. point
sampling for triangles), at a given pixel the depth computed
for the edge line usually differs from the depth computed
for the underlying triangle. This can cause ``stitching'' or
other unpleasant artifacts in the image, because depth buffering
sometimes places the line in front of the triangle and sometimes
behind it.
How much separation is needed to ensure that the line is always
in front of the triangle? If you look at the rasterization
arithmetic or play with a few diagrams, you can see that at some
pixels the depth value for the triangle is computed at a point
almost one pixel away from the ideal edge (which produces the
depth values for the line). Since the triangle can have an almost
arbitrarily large depth slope, there is no fixed offset that will
guarantee separation between the two primitives in all cases.
However, a (variable) separation of 1.0 times the depth slope of
the triangle is always sufficient. (For the purposes of this
discussion, the depth slope is max(|dz/dx|,|dz/dy|). The spec
has additional information.) It's sometimes more than you need,
but it's always large enough to work.
If the line were two pixels wide rather than one, then 1.0
times the depth slope wouldn't be enough separation, because
some pixels on the line might have depth values derived from an
edge point more than one pixel away from the underlying point
on the triangle. 2.0 would be sufficient, though.
So now you understand the factor argument. It should be
nonzero when you're attempting to separate two primitives that
aren't parallel, and its value should be roughly the size of
the screen-space overlap (measured in pixels) between the two
primitives. For any given triangle, the factor is multiplied
by the triangle's depth slope to compute the amount of separation.
The ``units'' or ``bias'' argument provides separation in the case
where the primitives are roughly parallel. The value to use
depends on how many primitives you're trying to stack up.
Consider the edged-triangle case again. What happens when the
depth slope of the triangle is zero? Since the depth slope is
zero, no matter what the factor argument is, you won't get any
separation between the triangle and the edge line. However,
you still want some separation between the two primitives,
so that you get a consistent result (i.e., one that doesn't
depend on the order in which you draw things or on whether the
depth-comparison function tests for equality).
The bias argument guarantees a little separation even in the case
where the depth slope is zero. Furthermore, it generalizes to
the case where the depth slopes of the primitives are nonzero,
but the primitives are roughly parallel (for example, when using
one polygon as a decal on another).
The original version of polygon offset allowed you to specify
a bias that was simply added to the depth value at each pixel.
However, it was quite difficult to choose an appropriate value,
because the choice depends not only on the number of bits in the
depth buffer (offsets smaller than the depth buffer precision
don't do you much good!) but also on the precision of various
computations inside the OpenGL driver and the hardware.
Perspective projection can also make a difference, since
resolution is better at the near clipping plane than it is at
the far clipping plane.
The current version of polygon offset specifies the bias in
multiples of a ``minimum resolvable difference,'' which is some
value determined by the driver developer. The minimum resolvable
difference is sufficient to separate two parallel primitives,
taking into account the perspective projection, size of the
depth buffer, hardware precision, etc.
Since one unit is sufficient to separate two primitives, you
can use more than one unit to separate additional primitives.
For example, by using bias values of 1, 2, 3, ... you can stack
up an arbitrary set of polygons on a base polygon.
Since some OpenGL implementations add the bias before the
perspective divide, a bias of 1.0 unit might be much larger
than is needed for primitives close to the near clipping plane.
If your app is smart enough to know exactly how the driver
behaves, and roughly where in the view volume the primitives
will fall, then it can use a bias of less than 1.0 to separate
primitives close to the near clipping plane. Most of the time
this is *not* worth the effort, though.
Some practical examples:
Drawing lines of width 1.0 pixel on the edge of a triangle
should use a factor of 1.0 (to guarantee separation when the
triangle depth slope is nonzero) and a bias of 1.0 (to guarantee
separation when the triangle depth slope is zero).
Drawing wider lines requires larger factors. A good rule of
thumb might be to use a factor equal to ceil(lineWidth/2 + 0.5).
Drawing decal polygons needs a zero factor and a nonzero bias,
provided that you can guarantee that all of the vertices of
the decal polygons are on the same side of the plane of the
base polygon, and not on that plane. (If intersections occur,
you might need a nonzero factor, because the depth slopes of
the primitives might be different.) Use a bias of 1.0 for the
lowest-level decal (the one closest to the base), 2.0 for the
next-highest, and so on.
Positive factors and biases push primitives in one direction;
negative factors and biases push primitives in the other
direction. Sometimes it makes a difference (for example, if you
want to use the values in the depth buffer for a subsequent pass).
If you run into trouble, the most likely cause is that the driver
developer underestimated the value of the minimum resolvable difference.
(I know of no way to predict this value; I think you just have to
measure it. The basic idea is to binary-search across the range of depth
values, drawing two parallel polygons at each stage and determining if
depth-buffering artifacts occur. Do this once at the near plane, and
once at the far plane, and take the largest result. Repeat for extreme
depthrange values.) Tweaking the bias argument is probably the only
way to resolve this. :-)
Finally, as Steve Baker and I have discussed in the past, the
reference_plane extension is often a cleaner solution than polygon offset,
if your OpenGL implementation supports it.
Allen
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From fatcity!root@news.cts.com Fri Jan 16 04:45:15 1998
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Subject: Re: glPolygonOffset
Date: Fri, 16 Jan 1998 02:06:11 -0800
opengl-gamedev,
> At one time I came across web site with example for glPolygonOffset, but I
> can not find it again. Does anybody know web site.
Polygon offset is used to "lift" the projected planar shadows off of
the floor to avoid Z fighting in my dinoshade.c example. See:
http://reality.sgi.com/mjk/tips/TexShadowReflectLight.html
Other cool OpenGL rendering techniques are shown at:
http://reality.sgi.com/mjk/tips/
There are also several polygon offset examples in the GLUT 3.6 source
code distribution. See:
http://reality.sgi.com/mjk/glut3/glut3.html
In particular, look at:
progs/examples/origami.c
progs/examples/surfgrid.c
progs/examples/dinoshade.c
progs/examples/halomagic.c
progs/redbook/polyoff.c
progs/advanced/haloed.c
I hope this helps.
- Mark
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From fatcity!root@news.cts.com Mon Jan 5 14:50:59 1998
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Subject: Re: [Q] OpenGL + Arbitrary display mode in Win32
Date: Mon, 05 Jan 1998 12:03:38 -0800
Doty, Lee wrote:
>
> Any sound gurus out there? I agree that if we could get 3d sound in
> there, life would get exponentially happier.
I'm willing to donate the sound code from bzflag. It's supports:
arbitrary number of simultaneous sounds (limited by CPU speed)
attenuation with distance
propagation delay
doppler effects
stereo panning
It runs in a separate thread and has a very simple interface. I have
it running on Windows 95/NT and Irix, and Daryll Strauss ported it to
Linux. The Windows version would work better if DirectSound didn't
suck so bad, but it works reasonably well now.
A drawback is that it can suck up a lot of CPU time since it has to
do its own filtering and mixing. It also needs support for a better
HRTF, reverb with distance, high-frequency rolloff with distance, and
a way to set the volume on individual sounds. That last one is trivial
but the others are more involved.
Mark, you interested? I've also got fullscreen and resolution changing
code for Irix.
Cheers,
-chris
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From crs@millpond.engr.sgi.com Mon Jan 5 15:36:10 1998
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In-Reply-To: <199801052103.PAA30512@kenai.me.umn.edu> from "Curtis L. Olson" at Jan 5, 98 03:03:52 pm
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From: crs@millpond.engr.sgi.com (Chris Schoeneman)
To: curt@me.umn.edu (Curtis L. Olson)
Subject: Re: bzflag sound playing code
Date: Mon, 5 Jan 1998 13:35:59 -0800 (PST)
Curtis L. Olson wrote:
>
> Is the licensing of the bzflag sound code such that I could use it to
> build in sounds support for our project? We would want to have a
> continuously looping engine sound (plus wind sound, and maybe rain
> hitting the windshield sound.) Then we'd need to intersperse the
> other sounds such as flaps, stall horn, landing gear, thunder, crash,
> etc. It sounds like it might be exactly the sort of thing we need.
Hmm, it's not a perfect match. Most of your sounds are purely local,
so you don't need the stereo panning, propagation delay, and doppler
effect. However, that's no reason not to try it!
Ripping my sound code out from bzflag shouldn't be too much work
but I'm really busy at the moment. Could you wait about a week?
BTW, as far as licensing goes I'd just want the copyright notice to
stay on the source files (we'll have to tweek the legal notice) and
a mention in the credits, if you have a credits list. A right to
use enhancements to the code would be cool, too.
Cheers,
-chris
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In-Reply-To: <199801052204.QAA31163@kenai.me.umn.edu> from "Curtis L. Olson" at Jan 5, 98 04:04:44 pm
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From: crs@millpond.engr.sgi.com (Chris Schoeneman)
To: curt@me.umn.edu (Curtis L. Olson)
Subject: Re: bzflag sound playing code
Date: Mon, 5 Jan 1998 14:22:22 -0800 (PST)
Curtis L. Olson wrote:
>
> Does your code support continuously looping sounds? Or would this be
> fairly straight forward to implement? I've done virtually nothing
> with sound in my life other than listen to it. :-)
It does/should. bzflag doesn't use this code though so it may suffer
from bit rot. I used it to test the Doppler effect.
There may also be some issues around having a very large world. Imagine
the sound as a spherical shell. Outside the shell, sound hasn't reached
you yet; inside the shell, the sound has passed by. In bzflag I need
to keep sounds around for as long as any part of the shell is inside the
world because it's possible to move from one place to another instantly.
Seems to me you have this same situation if you want external views.
The sound engine is clever enough not to process sounds unless you're in
the shell, so a large world probably won't cause any problems. I'm just
not sure at the moment.
> This all sounds completely reasonable. All our stuff is released
> under the basic "GPL".
Should be fine. I've no problem releasing my code under the GPL.
Cheers,
-chris
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In-Reply-To: <199801052322.RAA32525@kenai.me.umn.edu> from "Curtis L. Olson" at Jan 5, 98 05:22:08 pm
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From: crs@millpond.engr.sgi.com (Chris Schoeneman)
To: curt@me.umn.edu (Curtis L. Olson)
Subject: Re: bzflag sound playing code
Date: Mon, 5 Jan 1998 15:32:53 -0800 (PST)
Curtis L. Olson wrote:
>
> Our code is all GPL'd, so if you can keep within those license
> restrictions feel free to borrow code. (Or does bzflag take place a
> long time ago in a galaxy far, far away ... I haven't tried running it
> yet myself.) :-)
Actually, it's already got accurate sun, moon, and stars. The star
magnitudes are relatively okay (there's not enough dynamic range on
a monitor anyway). You can specify any position on the earth, and
the positions are accurately based on the time and date. Great minds
think alike, eh?
I don't have the planets as I thought I'd gone overboard myself. Guess
I hadn't gone far enough!
Cheers,
-chris
From curt@me.umn.edu Thu Apr 30 09:02:28 1998
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["3542" "" "30" "April" "1998" "09:02:26" "-0500" "Curtis L. Olson" "curt@me.umn.edu" nil "88" "[comp.os.linux.announce] Enlightened Sound Daemon version 0.2" "^From:" nil nil "4" nil nil nil nil nil]
nil)
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From: curt@me.umn.edu (Curtis L. Olson)
Sender: curt@me.umn.edu
To: curt@me.umn.edu
Subject: [comp.os.linux.announce] Enlightened Sound Daemon version 0.2
Date: 30 Apr 1998 09:02:26 -0500
--
Curtis Olson University of MN, ME Dept.
curt@me.umn.edu
http://www.menet.umn.edu/~curt Try Linux!
------- Start of forwarded message -------
From: "Eric B. Mitchell" <emitchell@altaira.com>
Newsgroups: comp.os.linux.announce
Subject: Enlightened Sound Daemon version 0.2
Followup-To: comp.os.linux.misc
Date: Thu, 30 Apr 1998 08:25:43 GMT
Organization: Altair Aerospace Corporation
Message-ID: <pycola.893924743.30806@laulujoutsen.pc.helsinki.fi>
Reply-To: emitchell@altaira.com
-----BEGIN PGP SIGNED MESSAGE-----
I am pleased to announce the preliminary release of the
Enlightened Sound Daemon (EsounD version 0.2) for Linux.
More details at <URL:http://www.netcom.com/~ericmit/EsounD.html>.
This program is designed to mix together several digitized
audio streams for playback by a single device. The current
list of features includes the following functionality:
o A simple authentication scheme is implemented. The first
process to present a 16 byte key to the daemon determines
the ownership of the daemon. The owner of the daemon may
allow or disallow connections from other keys. If a HUP
signal is received, ownership of the daemon is reset.
o Playback of multiple digital samples simultaneously is
supported. The daemon uses a raw sample format which
is easily generated by the SOX utility from many other
data formats.
o The mixed audio data may be output from the daemon as a
"monitor" stream.
o Recording from the current input of the sound device is
supported. Full duplex operation (simultaneous recording
and playback) is supported.
o Client connections may cache samples for playback by an
assigned identification number. For example, a window
manager may cache samples in the server for playback on
various events, and play them back without replaying the
full audio stream for the sample. Samples may be looped
until the server receives a "stop sample" message.
Currently, the only platform supported is Linux. It is intended
that this program support multiple platforms. I have limited
access to other Unix platforms, so any help in porting the
Enlightened Sound Daemon to other platforms is appreciated.
The amp program, by Tomislav Uzelac may be a good reference
for porting the audio interface to other platforms.
This is to be considered an alpha release, as functionality
remains to be implemented.
- -- ebm
+=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=+
| __ a.k.a. Eric B. Mitchell |
| |_) . _ _| _| _ ericmit@ix.netcom.com |
| | \ ( (_ (_| (_| (_| (/_ www.netcom.com/~ericmit |
| How's My Programming? Call: 1 - 800 - DEV - NULL |
+=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=+
- --
This article has been digitally signed by the moderator, using PGP.
http://www.iki.fi/mjr/cola-public-key.asc has PGP key for validating signature.
Send submissions for comp.os.linux.announce to: linux-announce@news.ornl.gov
PLEASE remember a short description of the software and the LOCATION.
This group is archived at http://www.iki.fi/mjr/linux/cola.html
-----BEGIN PGP SIGNATURE-----
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Charset: latin1
iQCVAgUBNUg1h1rUI/eHXJZ5AQHjSwP/aGb9U1fIgnUA6qMaD6x/JeTM2IJVRLDa
YxXoZ9EbENIKCbV9lV0PcGogW0+eA2zAZq3tQFu9P9B+eFX6jcVD2FhDekvFI5ZS
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=Y1B3
-----END PGP SIGNATURE-----
------- End of forwarded message -------

85
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@ -0,0 +1,85 @@
From owner-fgfs-devel@flightgear.org Fri Mar 12 12:57:31 1999
X-VM-v5-Data: ([nil nil nil nil t nil nil nil nil]
["1824" "Fri" "12" "March" "1999" "12:55:14" "-0600" "Stephen J Baker" "sjbaker@hti.com" "<Pine.SGI.3.96.990312123905.8630A-100000@samantha.bgm.link.com>" "53" "[FGFS-Devel] Scene graph API." "^From:" nil nil "3" nil nil nil nil nil]
nil)
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Reply-To: fgfs-devel@flightgear.org
From: "Stephen J Baker" <sjbaker@hti.com>
Sender: owner-fgfs-devel@flightgear.org
To: Flight Gear Mailing List <fgfs-devel@flightgear.org>
Subject: [FGFS-Devel] Scene graph API.
Date: Fri, 12 Mar 1999 12:55:14 -0600 (CST)
I have just posted an early (pre-alpha - whatever) version of my
new Scene Graph API and simple matrix/vector math library onto my
web site:
http://www.woodsoup.org/~sbaker/ssg
...and...
http://www.woodsoup.org/~sbaker/sg
...these are the libraries that I'm using in my Tux-the-Penguin
game - so they *work* pretty well - but may not be as complete
or well-structured as they should be. There are also no example
programs (apart from the game itself) and the only file loader
is for an obscure ASCII format that nobody is likely to want
as a standard. I hope to fix that somewhat over then next few
weeks - but I'm on vacation next week.
I think these libraries could be applicable to FGFS in several
areas:
1) 3D instrument panels.
2) BUildings and other hand-created features like airfields,
detailed city areas and so forth.
3) Other aircraft.
There are some issues about how this would all integrate into
Curts terrain rendering scheme - but I think it's do-able.
Anyway, it would be nice if people would read the manuals
and email me some comments, criticisms, suggestions, etc.
Like I said though - these are really early cuts so don't
go out and write 100,000 lines of code that depend on
them - OK?
Since I'm going to be out in the wilds of Arkansas for the
next week (Do they have email out there? I *think* they
have phones), don't expect a quick answer to any questions.
Steve Baker (817)619-2657 (Vox/Vox-Mail)
Raytheon Systems Inc. (817)619-2466 (Fax)
Work: sjbaker@hti.com http://www.hti.com
Home: sjbaker1@airmail.net http://web2.airmail.net/sjbaker1
--
Please visit the FGFS web page: http://www.flightgear.org
For help on using this list (especially unsubscribing), send a message to
"fgfs-devel-request@flightgear.org" with a single line of text: "help".

153
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@ -0,0 +1,153 @@
From: Bernie Bright <bbright@c031.aone.net.au>
Sender: owner-fgfs-devel@flightgear.org
To: fgfs-devel@flightgear.org
Subject: Re: [FGFS-Devel] Another problem compiling Flightgear 0.55
Date: Mon, 02 Nov 1998 14:31:05 +1100
Arno Dabekaussen wrote:
>
> Hi Curt,
>
> Thanks for answerring my former post, but unfortunately the compilation
> blew up again.
> Here is the relevant information.
>
> With kind regards,
>
> Arno Dabekaussen
>
> Making all in Time
> make[2]: Entering directory
> `/home/arno/applications/FlightGear-0.55/Simulator/Time'
> c++ -DHAVE_CONFIG_H -I. -I../../././Simulator/Time -I../../Include
> -DHAVE_DAYLIGHT -DHAVE_TIMEZONE -I../.. -I../../Lib -I../../Simulator
> -I/usr/local/include -I/usr/X11R6/include -g -O2 -c event.cxx
> In file included from /usr/include/g++/std/bastring.h:571,
> from /usr/include/g++/std/string.h:6,
> from /usr/include/g++/string:5,
> from event.hxx:42,
> from event.cxx:48:
> /usr/include/g++/std/sinst.h:60: ambiguous template instantiation for
> `operator !=(const char *, const
> basic_string<char,string_char_traits<char> > &)' requested
[snip]
This is a known problem with the string class in g++ 2.7.x and is not
limited to FG. I've attached an unofficial patch to that fixes the
problem. Note, you'll need root access to apply the patch.
Cheers
Bernie.>From khan@xraylith.wisc.edu Wed Mar 05 02:21:24 1997
Path: news.mel.aone.net.au!news.mel.connect.com.au!munnari.OZ.AU!news.ecn.uoknor.edu!feed1.news.erols.com!newsfeeds.sol.net!uwm.edu!newsspool.doit.wisc.edu!news.doit.wisc.edu!khan
From: khan@xraylith.wisc.edu (Mumit Khan)
Newsgroups: gnu.g++.help
Subject: Re: Compiling with strings & vectors
Date: 4 Mar 1997 16:21:24 GMT
Organization: Center for X-ray Lithography, UW-Madison
Lines: 100
Message-ID: <5fhi64$lsa@news.doit.wisc.edu>
References: <5ffoh9$v2a$1@quartz.inquo.net>
NNTP-Posting-Host: modi.xraylith.wisc.edu
In article <5ffoh9$v2a$1@quartz.inquo.net>,
Travis Jensen <taj@viewpoint.com> wrote:
>I am trying to use a 'string' in a program compiled with 2.7.2.2
>and libg++ 2.7.2. If I just
>
> #include <string>
>
>and use it, I have no problems. However, if I
>
> #include <vector.h>
^^^^^^^^^^^^^^^^^^^
should be
#include <vector>
> #include <string>
>
>Is there something special I have to do to use strings and vectors
>together?
>
I've posted an unofficial patch to libstdc++ headers (no re-compilation
necessary, so it's easy!) something like 19 times so far. Here is a copy
of an old posting:
=====================================================================
If you're using GNU STL that comes with libg++-2.7.1, must apply the
following patch (no recompilation necessary):
% cd /usr/local/lib/g++-include/std
% patch -s -p0 < /tmp/libg++-2.7.1-patch
==== LIBG++ patch
*** bastring.h.org Sun Dec 3 10:51:44 1995
--- bastring.h Sun Dec 3 10:51:43 1995
***************
*** 523,529 ****
}
// Kludge this until g++ supports the new template overloading semantics.
! #if !defined(FUNCTION_H)
template <class charT, class traits>
inline bool
operator!= (const basic_string <charT, traits>& lhs,
--- 523,529 ----
}
// Kludge this until g++ supports the new template overloading semantics.
! #if !defined(FUNCTION_H) && !defined(OS_STL_FUNCTION_H)
template <class charT, class traits>
inline bool
operator!= (const basic_string <charT, traits>& lhs,
*** cinst.h.org Sun Dec 3 10:51:48 1995
--- cinst.h Sun Dec 3 10:51:47 1995
***************
*** 84,92 ****
--- 84,94 ----
__DO2(operator==,__B,__CCR,__CCR)
__DO2(operator==,__B,__CCR,__F)
__DO2(operator==,__B,__F,__CCR)
+ #if !defined(FUNCTION_H) && !defined(OS_STL_FUNCTION_H)
__DO2(operator!=,__B,__CCR,__CCR)
__DO2(operator!=,__B,__CCR,__F)
__DO2(operator!=,__B,__F,__CCR)
+ #endif
__DO1(abs,__F,__CCR)
__DO1(arg,__F,__CCR)
__DO2(polar,__C,__F,__F)
*** sinst.h.org Thu Feb 29 11:20:52 1996
--- sinst.h Thu Feb 29 11:21:22 1996
***************
*** 57,67 ****
--- 57,71 ----
// __DOPR (op, bool, wchar_t, __W)
__DOB (==)
+ #if !defined(FUNCTION_H) && !defined(OS_STL_FUNCTION_H)
__DOB (!=)
+ #endif
__DOB (<)
+ #if !defined(FUNCTION_H) && !defined(OS_STL_FUNCTION_H)
__DOB (>)
__DOB (<=)
__DOB (>=)
+ #endif
#undef __S
//#undef __W
==== END LIBG++ patch
Enjoy
Mumit -- khan@xraylith.wisc.edu
http://www.xraylith.wisc.edu/~khan/
Cc: gnu.g++.help,
Travis Jensen <taj@viewpoint.com>

251
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From fatcity!root@news.cts.com Sun Apr 12 22:32:55 1998
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X-Comment: OpenGL Game Developers Mailing List
X-Sender: Steve Baker <sbaker@link.com>
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From: Steve Baker <sbaker@link.com>
Sender: root@fatcity.com
To: Multiple recipients of list OPENGL-GAMEDEV-L <OPENGL-GAMEDEV-L@fatcity.com>
Subject: Re: Strips vs Fans ...
Date: Sun, 12 Apr 1998 19:50:31 -0800
On Sat, 11 Apr 1998, Edward M Povazan wrote:
> I've been following threads here about auto strip generation, and am
> starting to wonder, why not do fans. I did a small paper test ... a regular
> triangle grid.
> case : transforms per case : percentage less than seperate triangles
> seperate triangles : 144 : 0
> fans : 77 : 53%
> strips : 56 : 39%
>
> OK so strips win here. But on a general mesh (especially one optimized for
> rt3d) the strip runs are not as long. In fact, there are cases when fans
> produce less transforms than strips (this is the case in my landscape
> engine).
The other thing that leads me to get more excited about fans than
strips is that they tend to be more compact - spatially that is -
becuase they are all sharing that one vertex.
This is useful for pre-OpenGL culling since it greatly increases the
probablility that a fan will cleanly come out wither entirely inside
or entirely outside the view frustum. If (like me) you are using a
bounding sphere test to accept or reject entire strip/fan primitives
then it's easy to visualise how fans fit better into a neat sphere
than those long wandering strips.
I'm still struggling to convert an old terrain system which was based
around IRISGL primitives (alas, no fans) - and the wins for fans
seem pretty significant.
Steve Baker (817)619-8776 (Vox/Vox-Mail)
Raytheon Systems Inc. (817)619-4028 (Fax)
Work: SBaker@link.com http://www.hti.com
Home: SJBaker1@airmail.net http://web2.airmail.net/sjbaker1
--
Author: Steve Baker
INET: sbaker@link.com
Fat City Network Services -- (619) 538-5051 FAX: (619) 538-5051
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From sbaker@link.com Sun Aug 16 00:55:44 1998
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Reply-To: Steve Baker <sbaker@link.com>
In-Reply-To: <199808152138.QAA27557@kenai.me.umn.edu>
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From: Steve Baker <sbaker@link.com>
To: "Curtis L. Olson" <curt@me.umn.edu>
Subject: Re: strips vs. fans
Date: Sun, 16 Aug 1998 00:52:12 -0500 (CDT)
On Sat, 15 Aug 1998, Curtis L. Olson wrote:
> At one point did you suggest that I might have comperable performance
> with fans vs. tri-strips?
Yes. We went down the path of changing our terrain tools to use
fans - the performance was essentially unchanged.
In the end, it depends on the average number of vertices per triangle.
For very long tristrips, or for very large fans, the average tends
towards 1 vertex per triangle. In this respect, there is no performance
difference between strips and fans. However, there are two reasons
to prefer strips and one reason to prefer fans:
1) Strips are allegedly implemented in hardware for Voodoo-2, and
when Mesa supports that, there could be some savings to be had
in triangle setup times. I have not heard that the same is true
for tri-fans - but it's possible.
2) Strips can potentially contain more triangles than fans because
they are not limited to having all their triangles share that
one start vertex. If you can actually make your strips longer
for practical data then strips should win. However, it's quite
hard to get an average strip strip length more than four or
five when your terrain has features like lakes, rivers, forest,
etc embedded in it.
3) Fans have one theoretical advantage - since all the triangles
share that first vertex, fans tend to be spatially compact.
This means that crude bounding sphere culling will be more
effective at reducing the number of triangles sent to OpenGL
than it might be with tri-strips.
My practical experience so far seems to suggest that these
various effects are either so tiny as to make no difference - or
somehow cancel out. However, it's work-in-progress.
Steve Baker (817)619-2657 (Vox/Vox-Mail)
Raytheon Systems Inc. (817)619-4028 (Fax)
Work: SBaker@link.com http://www.hti.com
Home: SJBaker1@airmail.net http://web2.airmail.net/sjbaker1
From sbaker@link.com Tue Aug 18 08:57:29 1998
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From: Steve Baker <sbaker@link.com>
To: "Curtis L. Olson" <curt@me.umn.edu>
Subject: Re: strips vs. fans
Date: Tue, 18 Aug 1998 08:56:05 -0500 (CDT)
On Mon, 17 Aug 1998, Curtis L. Olson wrote:
> So do just use a "greedy" algorithm to build fans, or do you do
> something more sophisticated?
Well, we have to consider the larger issues.
* From the point of view of OpenGL, the more triangles in the strip/fan
the better.
* From the point of view of FOV culling, the more compact the strip/fan
the better.
* From the point of view of intersection testing, the shorter the strip/fan
the better.
We use a variety of stripping algorithms depending on the cicumstance.
Sometimes we just do the 'greedy' algorithm, sometimes we impose a limit
on the maximum strip length which tends to cut down on the number of
single triangles (which are especially costly on SGI hardware for some
reason). Sometimes we use an algorithm that has an estimate of the
relative costs of transforming strips of length 1, 2, 3, 4, ... which
tries many different ways to strip/fan until it finds one with a cost
per-triangle that is less than some user-specified limit - and the
ultimate algorithm simply does a totally exhaustive search for the cheapest
overall set of strips.
The last few algorithms can take days to run on even relatively simple
objects - and we use those only for the simplest of objects when that object
is re-used a gazillion times in the database. For example, we did a
model of Yellowstone national park where the customer needed the highest
possible density of single, individual trees. We built a set of tree
cluster models and ran the tri-stripper at maximum optimisation on them
all to get down the cost of transforming all those thousands of trees to
the absolute minimum.
However, when we have the whole of North America to tstrip, we can't
afford the CPU hours to do anything much more than the very basic
limited-length-greedy algorithm.
Limiting the maximum strip length helps the FOV culling so much that
we pretty much always limit the length to a dozen of so triangles.
That's principally due to SGI hardware which gains performance as the
strip length increases - up to about 10 triangles - beyond which it
doesn't really help any.
It's MUCH better (on SGI ONYX hardware) to generate two strips of 5
triangles each than it is to generate one strip of 9 and one single
triangle.
For us, there are yet other considerations. We don't currently drive
OpenGL directly - we use the Performer scene graph API as a layer on
top. Performer can optimise the case where all the triangles in the
strip share the same surface normal and/or colour. In that case, it
generates just one glNormal and glColor command for each strip. These
are called 'Flat-Tri-strips'. For man-made objects, we can often win
by having shorter strips that are flat rather than longer strips that
are non-flat because the cost of transforming the normals is not
negligable.
Some of the SGI machines also optimise for the case when there is only
a single, infinite light source by only doing illumination per-normal
rather than per-vertex - this also makes flat strips worth having.
Some of these optimisations are actually pessimisations on some machines,
so you have to optimise the database for the hardware.
As you can see, this is another incredibly complicated issue if you
want to get absolutely *ALL* the performance you can.
It's unreasonable to expect FGFS to do this with the limited effort
available. We have two or three full-time staff thinking about
database tools - and we have been working with OpenGL for five
years now.
> > 1) Strips are allegedly implemented in hardware for Voodoo-2, and
> > when Mesa supports that, there could be some savings to be had in
> > triangle setup times. I have not heard that the same is true for
> > tri-fans - but it's possible.
>
> I would think that if they did strips, they could easily do fans ...
I just asked the question on the 3Dfx newsgroup - we'll get a definitive
answer there.
Steve Baker (817)619-2657 (Vox/Vox-Mail)
Raytheon Systems Inc. (817)619-4028 (Fax)
Work: SBaker@link.com http://www.hti.com
Home: SJBaker1@airmail.net http://web2.airmail.net/sjbaker1

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From: Steve Baker <sbaker@link.com>
To: "Curtis L. Olson" <curt@me.umn.edu>
Subject: Re: Question
Date: Tue, 26 May 1998 07:54:04 -0500 (CDT)
On Fri, 22 May 1998, Curtis L. Olson wrote:
> I'm running into floating point problems again where my scenery tiles
> sometimes have a pixel gap between them. I was wondering if you had
> any ideas ...
It's a problem that plagues us too.
I can't say that I have a magic solution.
One thing I have *considered* is to do everything in integers (for
the terrain skin at least).
This sounds counter-intuitive - but the source data for your
terrain is certainly not accurate to better than a meter - and
integers have the huge advantage that they don't suffer from
roundoff error providing all you do is add and subtract them.
However, I havn't had the nerve to try this yet - right now, we
kludge the edges of each terrain tile to make it a teeny-tiny bit
too big. The resulting overlap is very small - but enough to get
rid of the cracks.
> Anyways, what this forces me to do is for each tile I must
> glTranslate() by center_of_tile_to_be_drawn - center_of_tile_I'm_in.
> But, up until this point everything was done in double's so I was
> hoping the final translate about which is on the order of 20,000 -
> 30,000 meters would be ok.
But that translate could be done in integer meters.
> Anyways, I just thought I'd see if you had any brilliant thoughts on
> the subject.
Nope - it's a continual problem for me too.
Steve Baker (817)619-8776 (Vox/Vox-Mail)
Raytheon Systems Inc. (817)619-4028 (Fax)
Work: SBaker@link.com http://www.hti.com
Home: SJBaker1@airmail.net http://web2.airmail.net/sjbaker1

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>-----Original Message-----
>From: Antoine Leca [mailto:Antoine.Leca@renault.fr]
>Sent: Thursday, April 01, 1999 4:51 AM
>To: Lee Geoff
>Cc: tz@elsie.nci.nih.gov
>Subject: Re: storing timestamp data
>
>
>Lee Geoff wrote:
>>
>> I'm interested in storing date/time data in Ingres
>> databases which are running on Unix servers. We are
>recording timed events
>> on Unix servers as well as Windows 3.1 and NT PCs. I have
>had problems with
>> the apparent miss-handling of data when viewed before or after a DST
>> transition.
>
>We had this kind of problems when setting up a Internet
>standard for exchanging
>calendars, agendas and schedules (it ends up in RFC2245, if you mind).
>
>The net result was: either use UTC, or local time + offset from UTC.
>Do not use local time without UTC offset, as no reliable method can be
>set up to correctly retrieve the exact point of time
>afterwards (as you may
>have experienced).
>
>Using UTC times is native on Unix and NT (AFAIK), so this is
>the basic choice
>there. The problem comes with Windows non-NT PCs, since they
>run local clocks.
>IMHO, and to be consistent with the above, no data that are
>not tagged with
>the (best approximation of) UTC offset should leave the PC.
>
>Traditional way of finding the best approximation are (in order):
> - search for an (up to date) Olson's package to interpret the
>information,
> perhaps by searching $(DJDIR)/zoneinfo/localtime in addition to
> $(TZDIR)/localtime
> - if running on Windows 95/98, search the information in the registry
> - setting a mechanism dedicated to it (but it will end with one more
> mechanism, which tends to upset users)
> - ask the TZ environment variable
> - search the information on related softwares that may be
>present on the PCs
> (examples are mailing systems, e.g. Notes, and IP
>connectivity packages)
>
>Do not use:
> - tzset and timezone, as it defaults to PST8PDT or EST5EDT on
>most compilers,
> without being reliably accurate on most workstations by lack of TZ
> - if your users are not Americans, do not rely on US-based
>rules; they are
> almost correct for Europeans (except that for example, this
>week, my UTC
> offset is wrong because my mail software is brocken on this
>respect...)
>
>
>Hope it helps,
>
>Antoine
>
>

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From: Steve Baker <sbaker@link.com>
To: "Curtis L. Olson" <curt@me.umn.edu>
Subject: Re: View frustum culling
Date: Thu, 29 Jan 1998 23:16:36 -0600 (CST)
On Thu, 29 Jan 1998, Curtis L. Olson wrote:
> Questions ...
>
> Let's say I know the following:
>
> Eye pt. = (0, 0, 0)
> "look at" vector
> "view up" vector
> field of view angle
> Assume a "square" view volume cross section (i.e. the far clip plane
> would be a square)
(That is almost never the case since you want the image to fit the
screen shape - but OK - for argument's sake, same HFOV as VFOV).
> I can calcuation the near and far clip planes pretty easily with this
> info.
Assuming you know the near and far clip ranges - yes.
> Now, to calculate the left and right planes I could rotate the look at
> vector about the view up vector by -1/2 * fov and +1/2 * fov
> respectively. The view up vector already lies in both these planes,
> so then I'd have two vectors in each plane and then I could calculate
> the normals to get the equations of these planes
Yes, that would work.
> Then to calculate the top and bottom planes I could rotate the view up
> vector by 90 degrees about the look at vector to get a vector in both
> these planes, then I could rotate the look at vector about this new
> vector by -1/2 * fov and +1/2 * fov to get the second vector in each
> of these planes, and crunch the math just like I did for the left and
> right planes.
...or you could just rotate the left or right plane normal by 90 degrees
about the lookat vector (but only for your hypothetical square FOV).
> Does this sound reasonable, or am I missing some obvious tricks?
It's *reasonable* if you want the view planes in the coordinate system
of the world. However, I'd argue about that premise.
I did the opposite - I keep the view frustum in the coordinate system
of the eye and rotate the world into that coordinate system. This
costs at most one extra transform (by the inverse of the eye-rel-world
matrix) per frame (at the root of the database tree).
The advantages are *huge* in the clipping code (which is where I
assume you are going with this question) since the plane equations
for the near and far planes (in eye coordinates) are trivial:
General Equation of a Plane:
Ax + By + Cz + D == 0
Far clip plane:
A == 0 ;
B == 0 ;
C == -1 ;
D == far_clip_range ;
Near clip plane:
A == 0 ;
B == 0 ;
C == 1 ;
D == -near_clip_range ;
Also, since the left and right clip planes are now vertical, we
know that B==0 and for the top and bottom planes, A==0.
In addition, because of symmetry about the Z axis, the A of
the left plane is equal to -A for the right, and the B of
the top plane is equal to -B of the bottom.
Furthermore, since D is just the distance of the closest
point of the plane to the origin - and all four planes
go through the eyepoint - and that *is* the origin - that
means that the 'D' component of all four edge equations is
always zero.
Notice that since the frustum is in eye coordinates,
there is no need to worry about lookat or viewup vectors
since these are 0,0,1 and 0,1,0 respectively - and the
eye point is always at 0,0,0 by definition. This also
means that you only need to calculate those plane equations
once - rather than once per frame as with your scheme.
When you come to ask the question: "Is this bounding sphere
cleanly inside the frustum, cleanly outside the frustum or
(annoyingly) straddling it?", you will want to insert the
x,y,z of the center of the sphere (relative to the eye
in the 'eye' coordinate system) into each of the
six plane equations in turn to compute the distance from the
sphere center to the plane - and compare that to the radius
of the sphere. When you write out the math for this, using
the full plane equations (as you would have to do with your
scheme), you find that all those zeros and symmetry effects
result in some pretty amazing optimisations.
Additionally, this is the OpenGL way. You stuff your frustum
matrix into the 'PROJECTION_MATRIX', put the inverse of
your eyepoint transform into the MODELVIEW_MATRIX and proceed
to push/multiply/pop the transforms of each of the models onto
that same matrix. Notice that the frustum is never transformed
into world space.
I suggest you go back and re-read the last L-O-N-G email I
sent about clipping, I explain my suggested method there
in more detail.
Note that I'm not saying that what you propose is wrong -
just that IMHO (and *only* IMHO), my way is going to be
a lot simpler and cheaper to implement. However, there may
be other reasons to want to do it your way.
The complexity of MANY 3D graphics problems often depends
critically on your choice of coordinate system. For
clipping, doing the math in the eye coordinate system
results in a *tiny* amount of math per sphere tested.
If you ever need to do lighting calculations, then
carrying them out in a coordinate system with the
light source at the origin makes life a gazillion
times easier too. The same kinds of things will also
crop up in collision detection as well.
Steve Baker 817-619-8776 (Vox/Vox-Mail)
Raytheon Systems Inc. 817-619-4028 (Fax)
2200 Arlington Downs Road SBaker@link.com (eMail)
Arlington, Texas. TX 76005-6171 SJBaker1@airmail.net (Personal eMail)
http://www.hti.com http://web2.airmail.net/sjbaker1 (personal)
** Beware of Geeks bearing GIF's. **
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From: Steve Baker <sbaker@link.com>
To: "Curtis L. Olson" <curt@me.umn.edu>
Subject: Re: View frustum culling
Date: Fri, 30 Jan 1998 14:08:27 -0600 (CST)
On Fri, 30 Jan 1998, Curtis L. Olson wrote:
> Steve Baker writes:
> > I did the opposite - I keep the view frustum in the coordinate
> > system of the eye and rotate the world into that coordinate
> > system. This costs at most one extra transform (by the inverse of
> > the eye-rel-world matrix) per frame (at the root of the database
> > tree).
> >
> > I suggest you go back and re-read the last L-O-N-G email I sent
> > about clipping, I explain my suggested method there in more detail.
>
> Yes I have that in front of me. I guess it wasn't clear to me that
> you were using this greatly simplifed view frustum specially placed in
> eye coordinates.
That's the key to doing this stuff *quickly*.
> > The complexity of MANY 3D graphics problems often depends critically
> > on your choice of coordinate system. For clipping, doing the math in
> > the eye coordinate system results in a *tiny* amount of math per
> > sphere tested.
>
> Yes ... your description all makes sense and looks like it makes view
> frustum culling very simple to implement.
>
> Ok, so now I'm going to try to zero in a bit more on the source of my
> confusion, which involves getting from my world to your eye
> coordinates.
Let's adopt a naming convention for matrices here:
A_rel_B
means the matrix that positions objects in A relative to
the object B.
Some facts:
B_rel_A is just the inverse of A_rel_B.
A_rel_B * B_rel_C == A_rel_C
Hence: (for a flat-earth world - just for the moment)
If the eyepoint is 10km east of the origin (eyepoint.x == 10,000)
then:
eye_rel_world is a matrix that translates by 10000m in the X
direction.
world_rel_eye is the inverse of eye_rel_world - which in this
case is just a matrix that translates by -10000m in X.
Taking the inverse of a general matrix isn't nice - but for simple
rotate/translate matrices it isn't too bad - and you only do it
once per frame anyway.
> Lets say that I have a bunch of scenery tiles that are properly
> oriented, but translated to near (0, 0, 0) to avoid problems with
> "float" precision.
>
> I assume based on your previous message that you define your view
> frustum once at the beginning of your program in eye coordinates to
> simplify all this math.
Yep - you *might* want to allow the user to change it sometimes - but
basically, it's always the same number unless you resize the window,
zoom the image, etc.
> This moves the "hard" part to generating a transformation matrix that
> maps world coordinates into eye coordinates.
But world_rel_eye is just the inverse of eye_rel_world - and that's
just the rotation/translation of the eyepoint relative to some
arbitary point.
> You say ...
>
> > Additionally, this is the OpenGL way. You stuff your frustum matrix
> > into the 'PROJECTION_MATRIX', put the inverse of your eyepoint
> > transform into the MODELVIEW_MATRIX and proceed to push/multiply/pop
> > the transforms of each of the models onto that same matrix. Notice
> > that the frustum is never transformed into world space.
>
> Ok, so does this mean that every iteration I have to generate the
> world -> eye transformation matrix by hand ... i.e. calculate the
> first translation matrix, calculate the rotation matrix, calculate the
> second translation matrix, calculate the shear matrix, calculate the
> scaling matrix, and then combine all these together, then invert it
> and stuff it on the MODELVIEW stack?
Yes - except that the eye_rel_world isn't usually scaled or sheared or
anything. Just heading/pitch/roll/x/y/z.
> Or is there a way to get OpenGL to do this work for me?
No - not really - there is no glInvertMatrix (AFAIK) - and in any
case, on machines with geometry accelleration doing a glGetMatrix
is *death* to performance.
> If not, can I at least use OpenGL's rotates,
> and transformations to avoid spending two weeks debugging picky math
> routines?
No - don't debug new math routines either - let me find some out on the
web for you. I'm sure I know of a good set. I'll email you from home
tonight - I'm a bit busy right now.
Flight Gear will definitely need a good, robust set of math routines -
better to have a solid library than to try to kludge something in OpenGL.
Steve Baker 817-619-8776 (Vox/Vox-Mail)
Raytheon Systems Inc. 817-619-4028 (Fax)
2200 Arlington Downs Road SBaker@link.com (eMail)
Arlington, Texas. TX 76005-6171 SJBaker1@airmail.net (Personal eMail)
http://www.hti.com http://web2.airmail.net/sjbaker1 (personal)
** Beware of Geeks bearing GIF's. **
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From: Steve Baker <sbaker@link.com>
To: "Curtis L. Olson" <curt@me.umn.edu>
Subject: Re: View frustum culling
Date: Fri, 30 Jan 1998 22:52:31 -0600 (CST)
On Fri, 30 Jan 1998, Curtis L. Olson wrote:
> Steve Baker writes:
> > But world_rel_eye is just the inverse of eye_rel_world - and that's
> > just the rotation/translation of the eyepoint relative to some
> > arbitary point.
>
> Ok, from what you are saying, if I think about it, I've probably
> already got a suitable matrix or something close to it laying around
> someplace. I have a matrix that does the proper rotations to align
> world coordinates with the local "up" for the aircraft. I'd probably
> just need to pre-multiply the proper translation matrix with that
> rotate matrix, then invert it, and stuff it onto the MODELVIEW stack.
You *must* be doing the right thing at the start of the frame - or
how else would the graphics be coming out right? (Oh - unless you
are using that weird OpenGL 'lookat' function or something).
> > No - don't debug new math routines either - let me find some out on
> > the web for you. I'm sure I know of a good set. I'll email you from
> > home tonight - I'm a bit busy right now.
> >
> > Flight Gear will definitely need a good, robust set of math routines
> > - better to have a solid library than to try to kludge something in
> > OpenGL.
>
> You may scream when you hear this, or not, I'm not sure ... but I've
> been using the matrix and vector routines from SRGP and SPHIGS.
I don't know these - but it's hard to imagine how anyone could screw
up the implementation of a matrix math library - so they are probably OK.
I have accumulated by own matrix/quaternion library that I've used
for the last 10 years - every new project starts with it - and adds to
it, so now I don't even have to think about how to drive it. That's
a very liberating thing.
Another good source for a matrix lib is inside the Mesa sources. These
are particularly interesting because the latest Beta release has
super-optimised machine code for Intel CPU's under Linux as a conditional
compiled option. You'd need to copy and change the names of the routines
though to avoid the names clashing with the real Mesa routines.
One *IMPORTANT* thing is that when you invert the eye_rel_world matrix
to get world_rel_eye, don't use a general purpose matrix invert routine
since those are *REALLY* inefficient bits of code for matrices that
are guaranteed to be pure rotate/translate. Instead, just do this:
/*
This definition of a matrix is
easier to deal with than a float[16] -
but you can safely pass this kind
of matrix directly to OpenGL routines
like glMultMatrix and glLoadMatrix.
*/
typedef float fgMat [ 4 ][ 4 ] ;
/*
Transpose/Negate is a poor man's invert.
It can *only* be used when matrix is a
simple rotate-translate - but it's a
gazillion times faster than a full-blown
invert.
*/
void fgTransposeNegateMat( fgMat dst, fgMat src )
{
/* Transpose the 3x3 rotation sub-matrix */
dst[0][0] = src[0][0] ; dst[0][1] = src[1][0] ; dst[0][2] = src[2][0] ;
dst[1][0] = src[0][1] ; dst[1][1] = src[1][1] ; dst[1][2] = src[2][1] ;
dst[2][0] = src[0][2] ; dst[2][1] = src[1][2] ; dst[2][2] = src[2][2] ;
/* Negate the translate part */
dst[3][0] = -src[3][0] ; dst[3][1] = -src[3][1] ; dst[3][2] = -src[3][2] ;
/* Populate the rest */
dst[0][3] = dst[1][3] = dst[2][3] = 0.0f ; dst[3][3] = 1.0f ;
}
> Debugging the low level routines, though, is sometimes the easy part,
> debugging the usage of them is where it can often get hairy ... :-)
I agree - matrices are truly horrible to get your head around. Have
you looked into Quaternions yet? They are v.interesting for the
flight dynamics people because they don't suffer from 'gymbal lock'
like H,P,R angles and are easier to renormalize than matrices.
You don't want to use Quaternions for the main graphics code - but
it's easy to form a Matrix from a Quaternion - and Quaternions are
a much better way to represent rotation than the usual three angles.
Steve Baker 817-619-8776 (Vox/Vox-Mail)
Raytheon Systems Inc. 817-619-4028 (Fax)
2200 Arlington Downs Road SBaker@link.com (eMail)
Arlington, Texas. TX 76005-6171 SJBaker1@airmail.net (Personal eMail)
http://www.hti.com http://web2.airmail.net/sjbaker1 (personal)
** Beware of Geeks bearing GIF's. **
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From: Steve Baker <sbaker@link.com>
Sender: owner-flight-gear@me.umn.edu
To: flight-gear@me.umn.edu
Subject: Re: [FGFS] View Frustum Culling
Date: Tue, 19 May 1998 07:44:47 -0500 (CDT)
On Mon, 18 May 1998, Curtis L. Olson wrote:
> Steve Baker writes:
> > Are you only planning to cull at the tile level? You probably ought
> > to cull at the triangle strip level (at least on machines without
> > geometry hardware).
>
> You are always trying to make things more complicated ... :-)
It's my experience that things are perfectly capable of getting
more complicated without any help from me :-)
> > You can check a bounding sphere against the view frustum in about 4
> > multiplies and four additions - and you only need to do that for
> > spheres inside tiles that straddle the frustum. Each test that
> > excludes a tstrip will save a bunch of vertex transforms - so you
> > should get another big win in doing that.
>
> Ok, a couple of questions. Do you recommend pre-calculating and
> storing the bounding sphere info for each tri-strip in the data file,
> or should I calculate it at load time?
Well, since you only have one CPU to use for both rendering and
realtime database paging, you'll want to minimise the amount of
calculations when loading. The bounding sphere calculation
that most people do is very simple - you probably would want to do it
offline eventually - but you can probably do it on loading the database
for now just so you can get the culling stuff finished. So long as you
don't do it every frame you'll be OK in the short term.
The basic bounding sphere algorithm that most people (including me)
use is v.simple. Just find the maximum and minimum x, y and z values
in the data set, position the center of the sphere halfway between
the minimum and maximum in each axis - then go through the points
to find the one thats furthest from that center point - that distance
is the radius. (You can compare the square of the ranges to get the
longest range - so you only need to do one sqrt per sphere when you
need to compute the actual radius).
There has been some discussion of 'better' algorithms that (presumable)
produce tighter spheres than the simple method described above. On
my 'to do' list here at work is to evaluate these various algorithms to
see which actually produces the tightest spheres.
tighter spheres == better culling == lower polygon counts.
I'm pretty sceptical about these algorithms being *significantly*
better than the simple one - but even a few percent improvement
is worth having if I can do it offline and steal the code from
someone who can do 'math'.
This one looks interesting:
http://vision.ucsd.edu/~dwhite/ball.html
...although being iterative, I wouldn't want to do it in my
database loader code.
Same applies to this one:
http://cm.bell-labs.com/who/clarkson/center.html
Both have source code - which is just as well since I can't understand
the math behind either of them!
If your culling math starts to take too much time then you'll want to
do a hierarchical cull. If I were you though I'd probably just
do this:
for each terrain tile
{
if ( outside the frustum )
continue ;
if ( inside the frustum )
draw all the tristrips
else /* straddling the frustum */
{
for each tristrip
if ( inside or straddling the frustum )
draw the tristrip
}
}
(Of course 'draw the tristrip' might actually mean 'add the tristrip to
the appropriate bucket so we can draw it later')
> To impliment this sort of
> scheme I suppose I would need to keep each tri-strip in it's own
> display list.
Yep - but you need to do that so that you can....
> ...sort the objects into buckets by material properties.
Definitely. Switching material properties (especially texture map)
is very costly on most hardware OpenGL's. Sorting is an absolute
must once you start you use more than one kind of texture on the
terrain skin.
> I suppose this would entail defining material properties in the data
> file and otherwise sprucing up the data file format (and internal data
> structures) a bit.
Eventually.
Steve Baker (817)619-8776 (Vox/Vox-Mail)
Raytheon Systems Inc. (817)619-4028 (Fax)
Work: SBaker@link.com http://www.hti.com
Home: SJBaker1@airmail.net http://web2.airmail.net/sjbaker1
-------------------------------------
Please visit the FGFS web page: http://www.menet.umn.edu/~curt/fgfs/
For help on using this list (especially unsubscribing), send a message to
"flight-gear-request@me.umn.edu" with a single line of text: "help".
From sbaker@link.com Mon May 18 07:39:58 1998
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From: Steve Baker <sbaker@link.com>
To: "Curtis L. Olson" <curt@me.umn.edu>
Subject: Re: view frustum culling
Date: Mon, 18 May 1998 07:39:06 -0500 (CDT)
On Fri, 15 May 1998, Curtis L. Olson wrote:
> I was just planning to work out the math myself, but it's not coming
> out nearly as simple as what you had. The near/far clipping plane is
> trivial, but I was working through the sides and started to see a few
> sqrt()'s and such start to creep in, and I don't remember seeing this
> with your pseudo-code.
Certainly shouldn't need sqrt's.
How about this:
You said:
> Anyone know anything about view frustum culling?
Yep.
Two issues:
1) Scene hierarchy generation (offline).
2) Runtime culling.
Hierarchy:
==========
There are lots of ways to do this. I usually build an heirerchical description
of each terrain tile. I typically build a tree structure that's organized
as follows:
| The World.
|
___________________|___
| | | | | | |
* * * * * * * Terrain tiles currently loaded
| | | | | | |
|
|
_____|_____
| | | |
* * * * Quarter-tiles
| | | |
|
|
_____|_____
| | | |
* * * * Sixteenth-tiles
| | | |
...and so on down until the number of polygons in each 'object' gets 'small enough'.
When you do this, don't try to split polygons when they cross a quarter or a
sixteenth tile boundary - just dump each polygon into the nearest 'bucket' to
it's centroid.
Do your tri-stripping on the leaf nodes of this tree - so that each tristrip
is contained entirely within one bucket.
Eventually, you will need to include buildings, roads, rivers, etc. Since these
need to be culled by level of detail, it is often useful to put them into a separate
tree structure that parallels the terrain 'skin' structure.
Finally, compute a bounding sphere around each leaf node, find the best fit
sphere by finding the maximum and minimim x, y and z of the tristrips in that
leaf node, taking the mid-point and then finding the vertex that is furthest
from that center point and using it as the radius.
Compute the bounding sphere for each level in the tree (everywhere where there is
a '*' in my diagram).
Runtime:
========
At runtime, you walk that tree every frame, testing the bounding sphere against
the view frustum.
* If the sphere lies entirely outside the view frustum then stop traversal
for that node. There is no need to test any of the nodes beneath this one
(we know that none of their leaf tristrips are visible).
* If the sphere lies entirely inside the view frustum then traverse immediately
to all of the leaves below this node without doing any more sphere testing
on them - draw all of the tristrips that are there. (We know they are all visible)
* If the sphere straddles the view frustum then check each daughter node in
turn by applying this algorithm on them recursively. If a leaf node straddles
the view frustrum then it's bad luck, you just draw all the tristrips it
contains and let OpenGL do the work.
You might also want to put a 'transition range' onto each node and if it
lies beyond that range cull it. You can also use this to conveniently
switch levels of detail by having multiple versions of each object in
the tree.
Testing a sphere against the View Frustum:
==========================================
In most cases, we can describe the volume of space that you can see
through the little glass window on the front of your CRT using a
Frustum (frequently mis-spelled as Frustrum or Fustrum even in some
text books).
A frustum is a truncated pyramid - which typically bounded by six
planes called:
NEAR, FAR, LEFT, RIGHT, TOP, BOTTOM
There are applications that require additional clipping planes (eg for
non-rectangular screens) - extending the work described in this
to cater for that is not hard).
In principal, all six planes can be constructed as general plane
equations:
A x + B y + C z + D == 0
However, for most applications, NEAR and FAR are parallel to the
screen, LEFT, RIGHT,TOP and BOTTOM all meet at the eye and the eye lies
along a vector that extends out from the center of the screen and is
perpendicular to it. This simplifies the equations considerably for
practical applications.
Transforms.
~~~~~~~~~~~
It is easiest to perform culling in a coordinate system where the
eyepoint is at the origin and the line from the eye through the center
of the screen lies along one major axis with the edges of the screen
parallel to the remaining two axes. This coordinate system is called
'Eye Space'.
Testing a Sphere against a Frustum.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
The most important thing to bear in mind about culling is that the
first trivial-reject test you apply is by far the most time-critical.
This test is always applied to more nodes than any of the subsequent
tests.
So, do the cheapest test first.
This is typically the NEAR plane test. Everything behind the viewers
head gets chopped out - and it's an especially cheap test.
if ( obj_sphere.center.z < near_plane - obj_sphere.radius )
REJECT!!
...next do the second cheapest test (assuming you know that your
database could possibly extend beyond the far clip plane)...
if ( obj_sphere.center.z - obj_sphere.radius > far_plane )
REJECT!!
...and *then* (for each of the other 4 planes) do...
if ( distance( obj.position, plane ) <= obj_sphere.radius )
REJECT!!
(The algorithm for computing that 'distance()' function is described
below).
It's also useful to know that in many applications, you cull more
objects from the left and right faces of the frustum than you do from
the top and bottom - so test left, then right, then bottom then top.
Also, with bounding sphere tests, you shouldn't forget to do
total-accept as well as total-reject tests. Once you know that an
object's sphere is TOTALLY on screen, you don't have to descend into
the daughter objects to cull-test them...you *know* they are all
on-screen.
Another way to look at that it to remember which of the six possible
plane tests didn't even touch the sphere - as you work your way down
the object hierarchy, you can accumulate those flags and avoid even
testing those planes that a parent sphere has already cleanly passed.
If you do this then a vast percentage of your spheres will only need to
be tested against one plane. However, for the normal case of a simple
frustum - when you examine the fully optimised
distance-of-point-from-plane code (below), you may well conclude that
this additional logic doesn't justify the paltry amount of additional
math that it might save.
Computing the Distance from Sphere Center to Clipping Plane.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
A plane can be represented by the equation
Ax + By + Cz + D = 0 ;
A,B,C is just the surface normal of the plane and D is the shortest
distance from the origin to the plane.
So, if you need to find the distance of a point from the plane, just
imagine a new plane that goes through your test point and is parallel
to the plane you want to test. The plane equation of that new plane
would be:
A'x + B'y + C'z + D' = 0 ;
Since the two planes are parallel, their surface normals are the same,
so
A' == A B' == B C' == C D' == D + distance_between_the_two_planes
...the only thing that's different is their D values - which differ by
the distance of your test point from the original plane.
So, for a point (x,y,z), the distance 'd' from the plane (A,B,C,D) is
derived as:
d = D' - D
= -A'x - B'y - C'z - D
= -Ax - By - Cz - D
= -( [ABC]dot[xyz] + D )
A dot-product of the point and the surface normal of the plane, plus
the distance from the plane to the origin. Three multiplies, three
additions and a negation.
As an aside - if you consider the point (x,y,z) as a FOUR element
homogeneous vector (x,y,z,w) then 'w' is 1.0 and you can compute the
distance by simply taking the four element dot-product of (A,B,C,D)
with (x,y,z,w). If you have fast 4x4 matrix math hardware in your
machine then you can use it to compute the distance from a point to all
four planes in a single operation!
That's the general result for an arbitary plane - but culling to the
view frustum is a very special case. If you are working in eye-relative
coordinates (IMHO this is best), then since all TOP,BOTTOM,LEFT,RIGHT
planes of the frustum meet at the eye - and since the eye is at the
origin (by definition), then D is always zero for those planes and that
saves you a subtract.
If you are feeling even more in need of optimisation - then you can
save one multiply per plane by realising that (for rectangular screens)
one of the three components of the plane equation will always be zero.
So, for the LEFT clip plane, the Y component of the normal of the plane
is zero, so the distance to the left or right plane is just
d = -( Ax + Cz )
...and to the top or bottom plane it's just:
d = -( By + Cz )
Furthermore, we know that the A component for the LEFT plane is just
the negation of the A component of the RIGHT plane, and the C component
is the same for both LEFT and RIGHT (and similarly, the B component of
the TOP plane, is the negation of the B component for the BOTTOM plane
and the C component is the same for both TOP and BOTTOM). This means
that you only need four multiplies and four additions to do the entire
job. (Since you are only using this for culling, you don't need the
minus sign - just reverse the conditional).
The NEAR and FAR planes are typically parallel to the X/Y plane. That
means that A and B are both zero and C is one (or minus-one) - but D is
not zero, so the math boils down to an add and a negate:
d = -(z + D)
Conclusions.
~~~~~~~~~~~~
Sphere-based culling can be extremely cost-effective. It's so cheap
that even if you feel the need to use a bounding cubeoid (or even a yet
more complex shape), it's still worth doing a sphere-based cull first
just to get rid of the trivial accept and reject cases.
Steve Baker (817)619-8776 (Vox/Vox-Mail)
Raytheon Systems Inc. (817)619-4028 (Fax)
Work: SBaker@link.com http://www.hti.com
Home: SJBaker1@airmail.net http://web2.airmail.net/sjbaker1
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From: Steve Baker <sbaker@link.com>
Sender: owner-flight-gear@me.umn.edu
To: flight-gear@me.umn.edu
Subject: Re: [FGFS] View frustum culling
Date: Tue, 26 May 1998 08:42:09 -0500 (CDT)
On Sat, 23 May 1998, Curtis L. Olson wrote:
> Gene Buckle writes:
> > If you want to email me a cygnus/mesa binary, I'd be happy to give
> > you new speed figures.
>
> Gene,
>
> The new binaries expect a modified scenery format. My impression for
> now based on culled vs. drawn percentages is that there was a much
> bigger jump between no culling and tile culling, than between tile
> culling and fragment culling.
That's to be expected...
(The eye is in the center of the diagram - looking up:
No Culling - draw this much:
________\_____________/________
| | \ | / | |
| | \ | / | |
|_______|___\___|___/___|_______|
| | \ | / | |
| | \ | / | |
|_______|______\|/______|_______|
| | | | |
| | | | |
|_______|_______|_______|_______|
| | | | |
| | | | |
|_______|_______|_______|_______|
Tile culling - draw this much:
_\_____________/_
| \ | / |
| \ | / |
|___\___|___/___|
| \ | / |
| \ | / |
|______\|/______|
Tile *and* tstrip culling - draw maybe this much:
\_____________/_
|_\ | /_|
|_\ | / |
|_\___|___/__|
|\ | /_|
|_\ | /_|
|\|/|
Clearly most of the savings were in the tile culling, but providing the
culling itself is done reasonably efficiently, the tstrip culling is
still worth-while.
Steve Baker (817)619-8776 (Vox/Vox-Mail)
Raytheon Systems Inc. (817)619-4028 (Fax)
Work: SBaker@link.com http://www.hti.com
Home: SJBaker1@airmail.net http://web2.airmail.net/sjbaker1
-------------------------------------
Please visit the FGFS web page: http://www.menet.umn.edu/~curt/fgfs/
For help on using this list (especially unsubscribing), send a message to
"flight-gear-request@me.umn.edu" with a single line of text: "help".

86
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@ -0,0 +1,86 @@
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To: Multiple recipients of list OPENGL-GAMEDEV-L <OPENGL-GAMEDEV-L@fatcity.com>
Subject: Re: How To Q: Off-screen object culling.
Date: Mon, 20 Apr 1998 07:50:34 -0800
On Sat, 18 Apr 1998, Jason Maskell wrote:
> This is probably an FAQ, but I'm to the point now where I need to be
> able to tell when one of my objects is offscreen and not even send it
> down the pipe. This would be pretty simple if I was using glFrustum,
> but I'm not at the moment. I could switch, but I haven't quite got my
> head around how to get the same results as I get using glPerspective..
> If someone can point me to some code that does some simple pre-culling,
> I would be most grateful.. >
Well, if you can do it with glFrustum then you can do it with
gluPerspective. Note that gluPerspective simply calls glFrustum.
It's like this:
void APIENTRY gluPerspective( GLdouble fovy, GLdouble aspect,
GLdouble zNear, GLdouble zFar )
{
GLdouble xmin, xmax, ymin, ymax;
ymax = zNear * tan( fovy * M_PI / 360.0 );
ymin = -ymax;
xmin = ymin * aspect;
xmax = ymax * aspect;
glFrustum( xmin, xmax, ymin, ymax, zNear, zFar );
}
[This is actually the source code for gluPerspective from the Mesa
library - but since it only involves regular OpenGL API, it should
work on any OpenGL implementation]
> BTW, I've bought the red book finally...
Always a good move. I have yet to hear anyone who regretted it.
Steve Baker (817)619-8776 (Vox/Vox-Mail)
Raytheon Systems Inc. (817)619-4028 (Fax)
Work: SBaker@link.com http://www.hti.com
Home: SJBaker1@airmail.net http://web2.airmail.net/sjbaker1
--
Author: Steve Baker
INET: sbaker@link.com
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also send the HELP command for other information (like subscribing).

112
Hints/win32-time-funcs Normal file
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@ -0,0 +1,112 @@
From nhv@laserplot.com Mon Mar 16 14:16:34 1998
X-VM-v5-Data: ([nil nil nil nil t nil nil nil nil]
["1740" "Mon" "16" "March" "1998" "15:11:22" "-0500" "Norman Vine" "nhv@laserplot.com" "<01BD50EE.348AEBC0.nhv@laserplot.com>" "84" "RE: Today's patches" "^From:" nil nil "3" nil nil nil nil nil]
nil)
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Message-ID: <01BD50EE.348AEBC0.nhv@laserplot.com>
Reply-To: "nhv@laserplot.com" <nhv@laserplot.com>
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From: Norman Vine <nhv@laserplot.com>
To: "'Curtis L. Olson'" <curt@me.umn.edu>
Subject: RE: Today's patches
Date: Mon, 16 Mar 1998 15:11:22 -0500
On Monday, March 16, 1998 2:31 PM, Curtis L. Olson [SMTP:curt@me.umn.edu] wrote:
> Norm,
>
> I got both your patches. Thanks! The first one looks good, I'll
> forward that over to the HUD guys.
>
> For the second one, could you try a little bit different fix? It
> seemed to work for me anyways. Somewhere in fg_time.c you'll see the
> following four lines:
>
> #ifdef WIN32
> int daylight;
> long int timezone;
> #endif /* WIN32 */
>
> Could you just try moving them to the top of the file (outside of any
> functions) so they have a "global" scope? I put 'em right before
> fgTimeInit().
Seems to work :-)
>
> I just did a quick test of this and I didn't see the sun jumping
> around. I really wish I knew how to get the real daylight savings
> time info out of a win32 machine ...
following time related stuff from CygWin headers
<Windows32/ Structures.h>
typedef struct _TIME_ZONE_INFORMATION {
LONG Bias;
WCHAR StandardName[ 32 ];
SYSTEMTIME StandardDate;
LONG StandardBias;
WCHAR DaylightName[ 32 ];
SYSTEMTIME DaylightDate;
LONG DaylightBias;
} TIME_ZONE_INFORMATION, *LPTIME_ZONE_INFORMATION;
typedef struct _SYSTEMTIME {
WORD wYear;
WORD wMonth;
WORD wDayOfWeek;
WORD wDay;
WORD wHour;
WORD wMinute;
WORD wSecond;
WORD wMilliseconds;
} SYSTEMTIME, *LPSYSTEMTIME;
!!!!!!!!!!!!!!!!!!!!!!
<Windows32/ Functions.h>
DWORD
STDCALL
GetTimeZoneInformation(
LPTIME_ZONE_INFORMATION lpTimeZoneInformation
);
VOID
STDCALL
GetSystemTime(
LPSYSTEMTIME lpSystemTime
);
VOID
STDCALL
GetLocalTime(
LPSYSTEMTIME lpSystemTime
);
DWORD
STDCALL
GetTickCount(
VOID
);
See Ya
Norman

View file

@ -89,6 +89,9 @@ public:
#endif /* _AUTO_PTR_HXX */
// $Log$
// Revision 1.1 1999/04/05 21:32:41 curt
// Initial revision
//
// Revision 1.2 1998/09/10 19:07:03 curt
// /Simulator/Objects/fragment.hxx
// Nested fgFACE inside fgFRAGMENT since its not used anywhere else.

View file

@ -42,6 +42,9 @@ extern const int DefaultViewMode;
// $Log$
// Revision 1.1 1999/04/05 21:32:41 curt
// Initial revision
//
// Revision 1.2 1998/02/16 16:17:36 curt
// Minor tweaks.
//

View file

@ -301,6 +301,9 @@ inline const_mem_fun_ref_t<_Ret,_Tp> mem_fun_ref(_Ret (_Tp::*__f)() const)
#endif // _COMPILER_H
// $Log$
// Revision 1.1 1999/04/05 21:32:40 curt
// Initial revision
//
// Revision 1.9 1999/03/02 00:36:31 curt
// Tweaks for native SGI compilers.
//

View file

@ -170,6 +170,9 @@ fgMethodCallback<T>::call0v( void** )
#endif // _FG_CALLBACK_HXX
// $Log$
// Revision 1.1 1999/04/05 21:32:41 curt
// Initial revision
//
// Revision 1.2 1998/09/15 02:09:04 curt
// Include/fg_callback.hxx
// Moved code inline to stop g++ 2.7 from complaining.

View file

@ -173,6 +173,9 @@
// $Log$
// Revision 1.1 1999/04/05 21:32:40 curt
// Initial revision
//
// Revision 1.13 1999/04/05 02:12:59 curt
// Define maximum nodes for a tile here.
//

View file

@ -59,6 +59,9 @@
// $Log$
// Revision 1.1 1999/04/05 21:32:40 curt
// Initial revision
//
// Revision 1.2 1998/12/09 18:47:39 curt
// Use C++ style comments.
//

View file

@ -2,6 +2,9 @@
// Alterations: Copyright C. Hotchkiss 1996
//
// $Log$
// Revision 1.1 1999/04/05 21:32:40 curt
// Initial revision
//
// Revision 1.2 1998/05/13 18:23:46 curt
// fg_typedefs.h: updated version by Charlie Hotchkiss
// general.h: moved fg_root info to fgOPTIONS structure.

View file

@ -82,7 +82,10 @@
/* $Log$
/* Revision 1.1 1998/04/28 21:41:39 curt
/* Initial revision of fg_zlib.h
/* Revision 1.1 1999/04/05 21:32:41 curt
/* Initial revision
/*
* Revision 1.1 1998/04/28 21:41:39 curt
* Initial revision of fg_zlib.h
*
*/

View file

@ -65,6 +65,9 @@ extern FGGeneral general;
// $Log$
// Revision 1.1 1999/04/05 21:32:40 curt
// Initial revision
//
// Revision 1.1 1999/01/06 21:47:39 curt
// renamed general.h to general.hxx
// More portability enhancements to compiler.h

View file

@ -1,139 +0,0 @@
/**********************************************\
* *
* W A R N I N G *
* *
* This file is now kept in reverse chronolog- *
* ical order so recent changes are now at the *
* top. *
* *
\**********************************************/
* 28th Sept 1889 -- Fixed a bug associated with exiting the
program with sounds still playing.
Fixed a bug associated with using the
package in the absence of a sound card.
Added a new member function "working"
which is the opposite of "not_working",
(as demanded by a bunch of rabid optimists)!
Fixed a couple of typo's in the manual.
* 23rd Sept 1998 -- The Good News: Finally got around to
getting the pitch envelope working. (Hooray)
The Bad News: This costs quite a bit in
performance - and it was a MAJOR rewrite
of significant parts of the internals,
so we may need some bug fixes.
This version is 0.5
* 7th July 1998 -- Fixed some error checking in slSample.cxx and
a missing declaration in sl.h
* 6th July 1998 -- Fixed an initialisation problem when
slScheduler was not a static/global.
Tom Knienieder's port to SGI/IRIX is now
working, documentation updated to reflect that.
* 16th June 1998 -- Added some slPortability.h fixes for
FreeBSD and the Cygnus WIN32 compiler.
Many thanks to Curt.
* 14th June 1998 -- Tom Knienieder's port to OpenBSD is now
working, documentation updated to reflect that.
Tom's improved Makefiles included, also some
example sound samples that were accidentally
left out of the release are now present.
A couple of typo's in the WIN32 section
have been fixed. The top level Makefile
now requires you to type 'make linux',
'make win' or 'make openbsd'.
* 13th June 1998 -- Tom Knienieder's port to WIN32 engine is now
working, documentation updated to reflect that
revised status. Some default constructor parameters
have changed, slDSP no longer supports setRate/setBps/setStereo.
You now have to delete the slDSP and recreate it with
new parameters. This makes porting a little easier.
'sound_test' renamed 'example'.
* 7th June 1998 -- Volume envelopes (and inverse volume envelopes)
now work correctly. Pan envelopes won't work
until stereo is implemented. Pitch and filter
envelopes turn out to be a major pain to implement
with the present slSceduler/slSamplePlayer interface,
so some significant internal changes are to be
expected.
Changed the CHANGES file to be in reverse
chronological order.
This version is officially SL v0.3 (beta)
* 3rd June 1998 -- Moved sample program and it's data files into
'example', moved documents into 'doc' and sources
into 'src'. Final library goes into 'lib'.
The entire preempting mechanism was broken -
now it's fixed.
Added a callback mechanism that allows
applications to know when a sound
loops, finishes playing, is pre-empted, etc.
New mechanisms added to stop/pause/resume a
playing sample.
All the documentation - and some of the code -
for slEnvelopes has been added, they don't
work yet - so don't bother with them for now.
Made some code a little more bullet-proof.
slSample's are now reference-counted so you
can't accidentally delete one while it's
playing without getting a FATAL error.
* 2nd June 1998 -- Fixed bug in initialisation that prevented SL
from functioning correctly in the case were there
is no sound card present.
This version is officially SL v0.2 (beta)
* 1st June 1998 -- Split library into two parts - libsm and
libsl. libsm contains only the Mixer class
since it is likely to be hard to port to
a lot of non-OSS systems - and most programs
won't need it anyway. Hence the documentation
has blossomed into three files and all the
'slMixer' references have turned into 'smMixer'.
Also, I finally got a hold of the OSS documentation,
which is a lot more complete - and straightened
me out on a few points. slDSP has changed
(internally) somewhat as a result and in particular,
you can no longer mess with the sampling rate,
stereo and bps settings after the slDSP or
slScheduler has been created. This also allows the
scheduler to enforce it's rule about only mono/8bps
operations.
I also added an 'autoMatch' function to the slSample
class to automagically match incoming samples to the
current slDSP/slScheduler. This makes using the library
a lot less painful and error-prone.
This version is officially SL v0.1 (beta)
We need a better name!
* 30th May 1998 -- Almost total rewrite, library can now
play multiple sounds without interruption,
supports '.WAV' and '.AU' file formats as
well as raw binary files. Able to copy with
much shorter safetyMargin on sound buffers,
and play without using the 'stop' call.
All class and external symbols now begin
with 'sl' or 'SL'. HTML documentation now
available.
* 27th May 1998 -- First hack

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@ -1 +0,0 @@
SUBDIRS = src example

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@ -1,9 +0,0 @@
NOTICE: This Sound Library (SL) distribution contains source code that is
placed into the public domain without copyright. These programs are freely
distributable without licensing fees. These programs are provided without
guarantee or warrantee expressed or implied.
If you use SL in a commercial or shareware product, it would be nice if you
gave credit where it is due. If you make any modifications or improvements
to SL, I would greatly appreciate a copy of the improved code.

View file

@ -1,9 +0,0 @@
Hi!
This is the fifth prototype of Steve's 'SL' sound library.
Check out 'CHANGES' and the new HTML documentation.
Steve

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@ -1,13 +0,0 @@
Building SL for Linux.
~~~~~~~~~~~~~~~~~~~~~~
% make freebsd
% su root
% make install
...that's all folks.
Header files go into /usr/include/SL (analogous to /usr/include/GL for graphics)
Library file(s) go into /usr/lib

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@ -1,13 +0,0 @@
Building SL for Linux.
~~~~~~~~~~~~~~~~~~~~~~
% make linux
% su root
% make install
...that's all folks.
Header files go into /usr/include/SL (analogous to /usr/include/GL for graphics)
Library file(s) go into /usr/lib

View file

@ -1,13 +0,0 @@
Building SL for OpenBSD.
~~~~~~~~~~~~~~~~~~~~~~~~
% make openbsd
% su root
% make install
...that's all folks.
Header files go into /usr/include/SL (analogous to /usr/include/GL for graphics)
Library file(s) go into /usr/lib

View file

@ -1,27 +0,0 @@
Building SL for SGI.
~~~~~~~~~~~~~~~~~~~~~~
There are two options, depending on whether you want to use GCC or
the standard SGI C++ compiler.
GNU G++:
% make sgigcc
% su root
% make install
SGI C++:
% make sgi
% su root
% make install
...that's all folks.
Header files go into /usr/include/SL (analogous to /usr/include/GL for graphics)
Library file(s) go into /usr/lib
When you link, be sure to include to -laudio

View file

@ -1,20 +0,0 @@
Building SL for UNIX
~~~~~~~~~~~~~~~~~~~~
If your UNIX box is Linux or OpenBSD then
check out README.linux or README.openbsd.
If your UNIX box supports OSS (the Open
Sound System) then in principal, you should
only need to type:
% make oss
% su root
% make install
...however, your milage may vary. If you succeed
in getting a non-Linux, non-OpenBSD version to
work, I'd like to hear about it.
Steve Baker <sjbaker1@airmail.net>

View file

@ -1,15 +0,0 @@
Building SL for win32 (msvc)
~~~~~~~~~~~~~~~~~~~~~~~~~~~~
C:>nmake win32
don't forget to set the environment !
example:
set include=c:\msdev\include;
set lib=c:\msdev\lib
path c:\msdev\bin;c:\bin;c:\winnt;......

View file

@ -146,6 +146,9 @@ void fgBucketDiff( const FGBucket& b1, const FGBucket& b2, int *dx, int *dy ) {
// $Log$
// Revision 1.1 1999/04/05 21:32:34 curt
// Initial revision
//
// Revision 1.4 1999/03/27 05:34:05 curt
// Elimitated some const warnings from the compiler.
//

View file

@ -330,6 +330,9 @@ operator== ( const FGBucket& b1, const FGBucket& b2 )
// $Log$
// Revision 1.1 1999/04/05 21:32:34 curt
// Initial revision
//
// Revision 1.8 1999/03/27 05:34:06 curt
// Elimitated some const warnings from the compiler.
//

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