This was done to clean up the license and to ensure that any commercial fork of the engine has to obey the far stricter requirements concerning source distribution. The old license was compatible with GPLv2 whereas combining GPLv2 and LGPLv3 force a license upgrade to GPLv3. The license of code that originates from ZDoomGL has not been changed.
Both of these were inherited from ZDoomGL and in terms of light design in maps it makes absolutely no sense to have them user configurable. They should have been removed 11 years ago.
Calling this function in the inner loop of a time critical rendering function apparently wreaks havoc with the CPU instruction cache - even though the function doesn't do anything substantial.
This needs some more in-depth investigation why just having that call can increase sprite rendering time by a factor of 10 and more if there's many lights in view.
- remove thing color from lighting calculations.
- implement alpha textures and inverse sprites for infrared as texture modes. This still requires some handling for the alpha texture mode for non-shader rendering because there is no way in the fixed pipeline to do it. The inverted texture effect can be done with a texture combiner.
- fixed: ThingColor for sprites was set in the wrong place. It must be in the Process function, not in the lighting calculation.
- added functions for isolated calculation of sprites' dynlight color.
