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.
* Instead of using the red channel it now uses the grayscale value. While slower in a few situations, it is also more precise and makes the feature more useful.
* For paletted textures do not use the index as alpha anymore but the actual grayscaled color. This is again to make the feature more consistent and useful.
* To compensate for the above there is now a list of hashes for known alpha textures in patch format, so that they don't get broken.
* IMGZ is now considered a grayscale format. There's only two known textures that use IMGZ for something else than crosshairs and those are explicitly handled.
* several smaller fixes.
* the actual color conversion functions for paletted output are now consolidated in a small number of inlines so that future changes are easier to do.
Note: This hasn't been tested yet and will need further changes in the hardware rendering code. As it is it is not production-ready.
GCC/Clang reported these warnings:
src/textures/jpegtexture.cpp:305:29: warning: data argument not used by format string [-Wformat-extra-args]
src/textures/jpegtexture.cpp:388:28: warning: data argument not used by format string [-Wformat-extra-args]
src/textures/jpegtexture.cpp:432:29: warning: data argument not used by format string [-Wformat-extra-args]
src/textures/jpegtexture.cpp:481:28: warning: data argument not used by format string [-Wformat-extra-args]
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.
Even though unlikely, this should work as a regular texture because it can be used as such.
As a result of the above, true color generation needs to be done explicitly now.
Until now each subclass of FTexture had to implement the entire span generation itself, presumably so that a few classes can use simpler structures.
This does not work if a texture can have more than one pixel buffer as is needed for alpha textures.
Even though it means that some classes will allocate more data now, it's the only way to do it properly.
In addition this removes a significant amount of mostly redundant code from the texture classes.
- added alpha texture processing to all converted classes
As of now this is not active and not tested.
Note that as part of the conversion even those textures that were working as alphatextures will not look correct until the higher level code gets adjusted.
This was implemented in a way that made it entirely impossible to load Build resources and make them usable for modding.
ZDoom had Build texture support for many years but the limitations the palette handling imposed made it impossible to use them.
It wasn't usable for anything more than to load Build maps and have them display properly - a feature that had to be removed because it was irreparably broken already.
With the forced palette override out of the way it should now be possible to implement loading of Build ART files as actually usable resources.
