This replaces the old redirection hackery that had to work differently for the legacy render path.
Overriding CopyTrueColorTranslated is far more robust and ensures that no edge cases can reach the GetPixels function, which wasn't the case before.
This theoretically means that the software renderer could access this data as well - if it just had been written with a more flexible texture interface.
However, as things stand, this may require quite a bit of work to achieve.
The old organization made sense when ZDoom still was a thing but now it'd be better if all pure data with no dependence on renderer implementation details was moved out.
A separation between GL2 and GL3+4 renderers looks to be inevitable and the more data is out of the renderer when that happens, the better.
This was originally invented to fix the sprite offsets for the hardware renderer.
Changed it so that it doesn't override the original offsets but acts as a second set.
A new CVAR has been added to allow controlling the behavior per renderer.
This was done mainly to reduce the amount of occurences of the word FTexture but it immediately helped detect two small and mostly harmless bugs that were found due to the stricter type checks.
The old logic used a translation table that does not work with color images, it was designed to handle 8 bit grayscale images.
So now, it creates a true color buffer and then turns it into a texture with R,G,B = 255 and the alpha channel set to the grayscale value.
This was also the reason why crosshairs made from 32 bit PNGs did not show correctly.
Now it is no longer necessary to provide specially set up textures for rendering shaded decals, they can use any PNG texture now that contains a proper red channel.
Handling of the alPh chunk has been removed as a result as it in no longer needed.
- now that the frame buffer stores its render time, the 'ms' return from I_GetTimeFrac is not needed anymore, we may just as well use the globally stored value instead.
The only feature this value was ever used for was texture warping.
Most of those which still rely on ZDoom's own definition should be gone, unfortunately the code in files that include Windows headers is a gigantic mess with DWORDs being longs there intead of ints, so this needs to be done with care. DWORD should only remain where the Windows type is actually wanted.
First, if it has already been determined the value should be left alone and second, for translated textures the generated buffer is inconclusive so in that case it cannot be used at all.
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.
This code was written under the assumption that the glGenerateMipmap function does not exist. But all supported hardware has this function through the GL_EXT_framebuffer_object extension.
