BC7 compression for dds

[Seakad]

BC7 much better DXT5, it would be nice to add it.

[Xottab-DUTY]

R4 now uses DirectXTex to load textures. That means, it supports BC7 now.

Update: I just successfully tested BC7 support and it is confirmed.

[Xottab-DUTY]

I'll use this issue as a general task for all BC1-7 formats.

Task list:

• [x] DirectX 11
  • [x] Use DirectXTex to load textures. (supports all BC formats)
• [x] DirectX 9 has been deprecated (#468)
  • [x] BC4/BC5 is also known as ATI1/ATI2. Check if ATI formats are supported and load as-is, or convert to DXT.
  • [x] Convert BC6H/BC7 to DXT or ATI.
• [ ] OpenGL
  • Check if corresponding extension is supported and convert it to other format if not.
  • [ ] BC1-3 (aka DXTn)
    • If this is not supported, all we can do is to just decompress the texture and load it in an uncompressed format.
    • https://github.com/KhronosGroup/OpenGL-Registry/blob/main/extensions/EXT/EXT_texture_compression_s3tc.txt
    • https://github.com/KhronosGroup/OpenGL-Registry/blob/main/extensions/EXT/EXT_texture_compression_dxt1.txt
    • https://github.com/KhronosGroup/OpenGL-Registry/blob/main/extensions/ANGLE/ANGLE_texture_compression_dxt.txt
  • [ ] BC4-5 (aka ATI1-2)
    • https://github.com/KhronosGroup/OpenGL-Registry/blob/main/extensions/ARB/ARB_texture_compression_rgtc.txt
    • https://github.com/KhronosGroup/OpenGL-Registry/blob/main/extensions/EXT/EXT_texture_compression_rgtc.txt
  • [ ] BC6H/BC7
    • https://github.com/KhronosGroup/OpenGL-Registry/blob/main/extensions/ARB/ARB_texture_compression_bptc.txt
    • https://github.com/KhronosGroup/OpenGL-Registry/blob/main/extensions/EXT/EXT_texture_compression_bptc.txt

Useful links:

• https://github.com/microsoft/DirectXTex/wiki/Decompress
• https://github.com/microsoft/DirectXTex/blob/main/DirectXTex/DirectXTexDDS.cpp#L60
• https://github.com/wine-mirror/wine/blob/master/dlls/wined3d/utils.c#L1475
• https://github.com/dolphin-emu/dolphin/pull/5834/files
• https://www.khronos.org/opengl/wiki/S3_Texture_Compression