This really serves no use anymore and is mostly a remnant of old times with dark CRT monitors. The default ambient level was set at 20, meaning a sector light level of 40. This is a value actual levels rarely get to, except when using some lighting effects - but it's for those that the ambient clamping did the most damage.
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.
- added colormap shader to postprocessing.
This replaces the in-place application of fullscreen colormaps if renderbuffers are active. This way the fully composed scene gets inverted, not each element on its own which is highly problematic for additively blended things.
- fixed: The shader code for handling special fixed colormaps did not use the color vertex attribute which was most evident with the 'shadow' render style on the spectre.
After thinking about it for a day or so I believe it's the best option to remove all compatibility code because it's a major obstacle for a transition to a core profile.
Turns out that the name doesn't accurately describe what it does.
It is correct for images that come with their own palette or are true color.
But for images using the game palette it doesn't use the red channel to determine translucency but the palette index! Ugh...
This means it cannot be done with a simple operation in the shader because it won't get a proper source image. The only solution is to create a separate texture.
- 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.
On GL 3.x+ this isn't needed at all and on older hardware it causes performance issues, in particular with hires textures due to impossibility of precaching.
In addition it forces some really awkward handling of lighting for things that have their own color, like stenciled sprites or particles.
With this special case gone it will be possible to handle this case in a saner manner than it is right now.
As compensation for older hardware a fullscreen blend will be drawn over the entire screen. This won't be 100% accurate but it's preferable to keeping the current method.
