This adds a mechanism for running generic operations at specific points
of the frame execution. This can be used by any part of the code an not
just Lua since it simply executes std::functions. It also adds an
"execution context" concept that specifies in which situation an
operation should be executed.
This is then used by the Lua Coroutines code for resuming coroutines at
specific points instead of always when the awaited promise resolves.
This is in preparation for using persistently mapped buffers for uniform
buffers. Since that functionality is not available in the OpenGL version
we are targetting I implemented a fall-back which simply uses
glBufferSubData.
I did a benchmark with these changes and there was no change in
performance to the current master version.
With the recent changes to how fog is handled in nebulas it is now
possible to render decals correctly in a nebula environment so there is
no need to disable decals when the mission is in a nebula.
This changes the decal system so that it is able to modify the normal
map of the scene. I tested this with some existing normal maps but I am
not entirely sure if the tangent matrix I construct uses the right
values so some additional testing with normal maps made specifically for
decals would be good.
This also fixed the issues introduced by the changes to how directional
lighting was handled. Now a decal can have a diffuse and a glow map. The
diffuse map is used to change the values of the color buffer and also
supports ambient lighting. The glow map renders into the emissive buffer
and should be used for effects that should not receive lighting.
This allows to render screen space decals into the deferred lighting
buffers no matter how complex the underlying geometry is.
Currently there is only limited support for using this in the engine.
Only weapon impact decals are supported at the moment for testing
purposes.
Goober5000