Matteo Bruni (@Mystral) commented about dlls/d3dx9_36/d3dx_helpers.c:
{ { 32, DDS_PF_FOURCC, MAKEFOURCC('D','X','T','3') }, D3DX_PIXEL_FORMAT_DXT3_UNORM }, { { 32, DDS_PF_FOURCC, MAKEFOURCC('D','X','T','4') }, D3DX_PIXEL_FORMAT_DXT4_UNORM }, { { 32, DDS_PF_FOURCC, MAKEFOURCC('D','X','T','5') }, D3DX_PIXEL_FORMAT_DXT5_UNORM }, + { { 32, DDS_PF_FOURCC, MAKEFOURCC('B','C','4','U') }, D3DX_PIXEL_FORMAT_BC4_UNORM }, + { { 32, DDS_PF_FOURCC, MAKEFOURCC('B','C','4','S') }, D3DX_PIXEL_FORMAT_BC4_SNORM }, + /* ATI2 is treated identically to BC5U in d3dx10+. */ + { { 32, DDS_PF_FOURCC, MAKEFOURCC('A','T','I','2') }, D3DX_PIXEL_FORMAT_BC5_UNORM },
I gather this is not supported on d3dx9? I don't see a test for it (although I wouldn't be surprised if I missed it in my cursory search). -- https://gitlab.winehq.org/wine/wine/-/merge_requests/8705#note_112444