Composite textures

Composite textures are graphics created by the engine from one or more other graphics. They are defined either in TEXTUREx lumps, as in vanilla Doom and the original engine for the other supported games; or with the more advanced TEXTURES lump.

When a texture is composited from a patch, the raw pixels from the patch are added to the texture, transformed if desired by translations, rotations, mirroring, or blending. The texture does not "remember" that it is made from this patch; a texture's graphic data, once composition is over, is only a collection of pixels. Special effects applied on a patch graphic (such as animation, or OpenGL brightmaps) are not transferred to the composite texture.