D942 - A texture whose keys are all uncompressed is read as plain texels

Status: decided Date: 2026-10-21 known_by: published

A texture descriptor may enable delta colour compression (COMPRESSION_EN, dword 6 bit 21) over a surface whose DCC keys all read 0xFF, every block stored uncompressed. Memory then holds the plain surface, and the texture is read as if compression were off. This is the state a colour target is left in once a frame is written back into it, its keys expanded (D714). It holds for one level of 64KB_R_X, whose key layout is modelled; a chain, another layout, or keys that say anything else is read as before.

Why: Grand Theft Auto V samples its 3840x2160 16_16_16_16_FLOAT scene target through a compressed descriptor after drawing into it, and every texture reader refused a compressed image.