- adjustments and fixes for alphatextures:

* 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.

src/textures/flattexture.cpp

@@ -112,8 +112,7 @@ uint8_t *FFlatTexture::MakeTexture (FRenderStyle style)
 	{
 		memset (Pixels + numread, 0xBB, Width*Height - numread);
 	}
-	if (!(style.Flags & STYLEF_RedIsAlpha)) FTexture::FlipSquareBlockRemap (Pixels, Width, Height, GPalette.Remap);
-	else FTexture::FlipSquareBlock(Pixels, Width, Height);
+	FTexture::FlipSquareBlockRemap(Pixels, Width, Height, GetRemap(style));
 	return Pixels;
 }