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flightgear/src/Main/viewer_lookat.cxx
david efe559ead4 First baby steps towards restructuring the view architecture. I've
created a new class, FGViewPoint (declared in viewer.hxx) that holds a
single position in FlightGear coordinates, and have used it to factor
a lot of the common code out of viewer_lookat.cxx and viewer_rph.cxx.

I don't know whether this new class will stay or not; it might just be
a temporary step, or it might end up taking over much of the current
viewer functionality.  It would be a bad idea to code against it right
now.
2002-03-06 16:03:33 +00:00

159 lines
4.8 KiB
C++

// viewer_lookat.hxx -- class for managing a "look at" viewer in
// the flightgear world.
//
// Written by Curtis Olson, started October 2000.
//
// Copyright (C) 2000 Curtis L. Olson - curt@flightgear.org
//
// This program 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 of the
// License, or (at your option) any later version.
//
// This program 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 this program; if not, write to the Free Software
// Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
//
// $Id$
#include <simgear/compiler.h>
#ifdef HAVE_CONFIG_H
# include <config.h>
#endif
#include <plib/ssg.h> // plib include
#include <simgear/constants.h>
#include <simgear/debug/logstream.hxx>
#include <simgear/math/point3d.hxx>
#include <simgear/math/polar3d.hxx>
#include <simgear/math/sg_geodesy.hxx>
#include <simgear/math/vector.hxx>
#include <Scenery/scenery.hxx>
#include "globals.hxx"
#include "viewer_lookat.hxx"
// Constructor
FGViewerLookAt::FGViewerLookAt( void )
{
set_reverse_view_offset(true);
}
void fgMakeLookAtMat4 ( sgMat4 dst, const sgVec3 eye, const sgVec3 center,
const sgVec3 up )
{
// Caveats:
// 1) In order to compute the line of sight, the eye point must not be equal
// to the center point.
// 2) The up vector must not be parallel to the line of sight from the eye
// to the center point.
/* Compute the direction vectors */
sgVec3 x,y,z;
/* Y vector = center - eye */
sgSubVec3 ( y, center, eye ) ;
/* Z vector = up */
sgCopyVec3 ( z, up ) ;
/* X vector = Y cross Z */
sgVectorProductVec3 ( x, y, z ) ;
/* Recompute Z = X cross Y */
sgVectorProductVec3 ( z, x, y ) ;
/* Normalize everything */
sgNormaliseVec3 ( x ) ;
sgNormaliseVec3 ( y ) ;
sgNormaliseVec3 ( z ) ;
/* Build the matrix */
#define M(row,col) dst[row][col]
M(0,0) = x[0]; M(0,1) = x[1]; M(0,2) = x[2]; M(0,3) = 0.0;
M(1,0) = y[0]; M(1,1) = y[1]; M(1,2) = y[2]; M(1,3) = 0.0;
M(2,0) = z[0]; M(2,1) = z[1]; M(2,2) = z[2]; M(2,3) = 0.0;
M(3,0) = eye[0]; M(3,1) = eye[1]; M(3,2) = eye[2]; M(3,3) = 1.0;
#undef M
}
// Update the view parameters
void FGViewerLookAt::update() {
sgVec3 minus_z;
view_point.setPosition(geod_view_pos[0] * SGD_RADIANS_TO_DEGREES,
geod_view_pos[1] * SGD_RADIANS_TO_DEGREES,
geod_view_pos[2] * SG_METER_TO_FEET);
sgCopyVec3(zero_elev, view_point.getZeroElevViewPos());
sgdCopyVec3(abs_view_pos, view_point.getAbsoluteViewPos());
sgCopyVec3(view_pos, view_point.getRelativeViewPos());
sgVec3 tmp_offset;
sgCopyVec3( tmp_offset, pilot_offset );
SG_LOG( SG_VIEW, SG_DEBUG, "tmp offset = "
<< tmp_offset[0] << "," << tmp_offset[1] << ","
<< tmp_offset[2] );
//!!!!!!!!!!!!!!!!!!!
// THIS IS THE EXPERIMENTAL VIEWING ANGLE SHIFTER
// THE MAJORITY OF THE WORK IS DONE IN GUI.CXX
extern float GuiQuat_mat[4][4];
sgXformPnt3( tmp_offset, tmp_offset, GuiQuat_mat );
SG_LOG( SG_VIEW, SG_DEBUG, "tmp_offset = "
<< tmp_offset[0] << "," << tmp_offset[1] << ","
<< tmp_offset[2] );
sgAddVec3( view_pos, tmp_offset );
// !!!!!!!!!! testing
// Make the VIEW matrix.
fgMakeLookAtMat4( VIEW, view_pos, view_forward, view_up );
// the VIEW matrix includes both rotation and translation. Let's
// knock out the translation part to make the VIEW_ROT matrix
sgCopyMat4( VIEW_ROT, VIEW );
VIEW_ROT[3][0] = VIEW_ROT[3][1] = VIEW_ROT[3][2] = 0.0;
// Make the world up rotation matrix
sgMakeRotMat4( UP,
geod_view_pos[0] * SGD_RADIANS_TO_DEGREES,
0.0,
-geod_view_pos[1] * SGD_RADIANS_TO_DEGREES );
// use a clever observation into the nature of our tranformation
// matrix to grab the world_up vector
sgSetVec3( world_up, UP[0][0], UP[0][1], UP[0][2] );
// Given a vector pointing straight down (-Z), map into onto the
// local plane representing "horizontal". This should give us the
// local direction for moving "south".
sgSetVec3( minus_z, 0.0, 0.0, -1.0 );
sgmap_vec_onto_cur_surface_plane(world_up, view_pos, minus_z,
surface_south);
sgNormalizeVec3(surface_south);
// now calculate the surface east vector
sgVec3 world_down;
sgNegateVec3(world_down, world_up);
sgVectorProductVec3(surface_east, surface_south, world_down);
set_clean();
}
// Destructor
FGViewerLookAt::~FGViewerLookAt( void ) {
}