Here are some things I've added to the submodel code.
First, I added a first_time value that is true when the trigger is pressed and
false when the trigger is released. The true value is also made false after
the first pass through release(). Release() then uses this to force the
first dt (per salvo) to be zero. I was hoping this would make the submodel
appear closer to the airplane, but I don't notice a difference with the
tracers. In a prior test I found that the first dt is about 2.5 times larger
than subsequent ones. Maybe this will be effective with slower submodels,
like smoke, contrails, etc.
Secondly, I updated the IC.elevation and IC.azimuth calcs to correctly add in
the yaw and pitch offsets, corrected for bank angle. Actually this is still
an estimation. A proper calculation will sum the submodels vector with the
airplane's vector. Until that's done only models which are fired forward
will have proper IC.
Testing revealed that the code was not reading y-offset - a
typo in the original code, and roll was in the wrong sense. All readily
fixable, and it now works.
I've added another parameter to the submodel - wind.
It's activated by the entry <wind>true</wind> in the ../submodel.xml file.
If true, the submodel is affected by the local wind, otherwise not. The
parameter defaults to false. This is useful for exhausts and smoke, and
possibly all objects.
Silly me. I was starting the timer at zero, so the first tracer didn't fly
until 0.25 seconds after pulling the trigger. Now the timer starts at the
same value as "delay", so the first round comes out immediately.
Also, I've added an optional configuration attribute that allows you to change
the ballistics of the submodel. This allows parachutes, or anything else
that has ballistics different from a bullet. The attribute is called "eda",
which is the equivalent drag area. Default value is 0.007, which gives the
same ballistics as the current tracers. Increasing this value gives more
drag. A value of 2.0 looks good for a parachute.
math stuff
########################################################################
The deceleration of the ballictic object is now given by:
[ (rho) (Cd) ] / [ (1/2) (m) ] * A * (V * V)
where rho is sea-level air density, and Cd and m are fixed, bullet-like
values. So the calculation is:
0.0116918 * A * (V * V)
The value "A" is what I'm calling the "eda" (equivalent drag area).
########################################################################
A parachute model will have to be built so that the parachutist's feet
are in the forward x-direction.
Here is the submodel.xml config I use for "parachutes":
<submodel>
<name>flares</name>
<model>Models/Geometry/flare.ac</model>
<trigger>systems/submodels/submodel[0]/trigger</trigger>
<speed>0.0</speed>
<repeat>true</repeat>
<delay>0.85</delay>
<count>4</count>
<x-offset>0.0</x-offset>
<y-offset>0.0</y-offset>
<z-offset>-4.0</z-offset>
<yaw-offset>0.0</yaw-offset>
<pitch-offset>0.0</pitch-offset>
<eda>2.0</eda>
</submodel>
Last night I sent these new files to Vivian to fix a problem he found. Since
we can have more than one submodel we need more than one "count" property.
The new code creates a property systems/submodels/submodel[n]/count for each
submodel. Vivian is using this count property for his sound.
Here is an update for the submodel system. This will allow submodels to be
defined for any aircraft, and there are no default submodels. To use this
submodel system you need to set up a binding (slight change in property name
from last one, but you can use any property name you like, as long as it
matches the name in the submodels.xml file, see below):
<button n="0">
<desc>Trigger</desc>
<binding>
<command>property-assign</command>
<property>/systems/submodels/trigger</property>
<value type="bool">true</value>
</binding>
<mod-up>
<binding>
<command>property-assign</command>
<property>/systems/submodels/trigger</property>
<value type="bool">false</value>
</binding>
</mod-up>
</button>
Then in your *-set.xml file you need to define a path to the configuration
file (similar to the way the electrical system is now done):
<sim>
...
<systems>
<electrical>
<path>Aircraft/Generic/generic-electrical.xml</path>
</electrical>
<submodels>
<serviceable type="bool">true</serviceable>
<path>Aircraft/FW190/submodels.xml</path>
</submodels>
</systems>
...
</sim>
Then you put the submodel configuration file in your aircraft's directory.
I've attached a file, submodels.xml, that can be used to define a gun that
works just like the former one did.
There are two things remaining to be done. One is to change the function
SubmodelSystem::transform() to properly position the submodel. This will
require some complicated matrix code that I might borrow from Yasim.
Well here's some tracer stuff. If fiddled around with submodel.cxx. It now
does what it says - you need to put this:
<!-- trial gun system -->
<systems>
<submodel>
<serviceable type="bool">true</serviceable>
<amount type="int">120</amount>
</submodel>
</systems>
In the *-set.xml file NOT within <sim></sim>. Trouble is it still defaults
to serviceable=true, but it also defaults to amount=0. Unless this bit of
code is included it wont run, so other models can't fire inappropriate
tracer. Revised submodel.cxx file attached.
I've changed to a non-billboard solution. I tried to make the viewing angle
of the tracer less than 180 degs, but failed. Close enough I think. It's
still a bit big, but a reasonable compromise. .AC file attached.
I remain concerned about the tracer colour. In practice, red is better (and
it's what I am used to) but David seems set on white, and I don't want to
upset him. I'm going to adjust the texture a bit more tomorrow.
Right now the code is not very configurable, and there is only one submodel per airplane possible. It is implemented as an SGSubSystem, just like the electrics, vacuum, etc. systems. To make it work you need to make a release binding like this (for my joystick trigger):
<button n="0">
<desc>Trigger</desc>
<binding>
<command>property-assign</command>
<property>/systems/submodel/trigger</property>
<value type="bool">true</value>
</binding>
<mod-up>
<binding>
<command>property-assign</command>
<property>/systems/submodel/trigger</property>
<value type="bool">false</value>
</binding>
</mod-up>
</button>
Then, each airplane that uses the system should have something like this added to its *-set.xml file (note that this does *not* go within the <sim></sim> tags):
<systems>
<submodel>
<serviceable type="bool">true</serviceable>
<amount type="int">70</amount>
</submodel>
</systems>
Future improvements will include:
1) more configurability, so the user can create multiple submodels, and can assign them different locations, and pitch and yaw adjustments, and nitial velocity.
2) sound?
3) a more accurate calculation of the submodels location at any pitch/roll/yaw.
4) a way to pre-load the model, so the AI code doesn't have to parse the model every time it creates an instance.
I think that's all of it.
a <rating-amps> tag which also implies that the switch is a circuit breaker.
Eventually we could have code that will automatically trip the breaker if
the current exceeds the rating.
support an attached property name and an intial state, but this can easily
be extended to configure a switch to be a circuit breaker with a max rating,
etc.
current draw. This is only one piece of the puzzle, but as we move forward,
the idea is better modeling of the ammeter, and we could automatically pop
circuit breakers if the current gets too high.
- Modified the rpm vs. suction formula to hit much more realistic numbers.
We should be seeing just over 4 inhg at idle and approaching 5 inhg at
full throttle.
scene management code and organizing it within simgear. My strategy is
to identify the code I want to move, and break it's direct flightgear
dependencies. Then it will be free to move over into the simgear package.
- Moved some property specific code into simgear/props/
- Split out the condition code from fgfs/src/Main/fg_props and put it
in it's own source file in simgear/props/
- Created a scene subdirectory for scenery, model, and material property
related code.
- Moved location.[ch]xx into simgear/scene/model/
- The location and condition code had dependencies on flightgear's global
state (all the globals-> stuff, the flightgear property tree, etc.) SimGear
code can't depend on it so that data has to be passed as parameters to the
functions/methods/constructors.
- This need to pass data as function parameters had a dramatic cascading
effect throughout the FlightGear code.
the whole electrical system. We will also need a mechanism to kill
individual suppliers (such as the alternator), but this is good enough
for most training.
Ok, I found the problem. You're computing the dynamic pressure in
"psf" and adding it to the static pressure in "inHg" to form the
total pressure. The attached patch is the simple fix to the source.
With that fix, failing the pitot while in cruise at 3k' will cause
the airspeed to indicate beyond redline during climb ... well before 4k'.
Thus, a pitot problem can be detected on any IFR altitude change.
Similarly, failing the static (with working pitot) while cruising 4k'
causes the airspeed to indicate beyond redline during a descent
well before reaching 3k' (during which, of course, the ALT looks fine).
Thus, a static failure can be detected before the aircraft breaks out
of the pilot tolerance range and is blatantly conspicuous soon after.
The code reads the electrical system config and contructs an internal model.
Nothing is done beyond that yet ... the electrical system is not updated,
nor is it connected to the property system in anyway.
