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DDS Texture Example

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For an uncompressed texture, use the DDSD_PITCH and DDPF_RGB flags; for a compressed texture, use the DDSD_LINEARSIZE and DDPF_FOURCC flags. For a mipmapped texture, use the DDSD_MIPMAPCOUNT, DDSCAPS_MIPMAP, and DDSCAPS_COMPLEX flags also as well as the mipmap count member. If mipmaps are generated, all levels down to 1-by-1 are usually written.

For a compressed texture, the size of each mipmap level image is typically one-fourth the size of the previous, with a minimum of 8 (DXT1) or 16 (DXT2-5) bytes (for square textures). Use the following formula to calculate the size of each level for a non-square texture:

max(1, ( (width + 3) / 4 ) ) x max(1, ( (height + 3) / 4 ) ) x 8(DXT1) or 16(DXT2-5)

This table lists the amount of space taken up by each layer for a 256-by-256 R8G8B8 texture, without using compression.

DDS Components # Bytes
header 128
256-by-256 main image 196608
128-by-128 mipmap image 49152
64-by-64 mipmap image 12288
32-by-32 mipmap image 3072
16-by-16 mipmap image 768
8-by-8 mipmap image 192
4-by-4 mipmap image 48
2-by-2 mipmap image 12
1-by-1 mipmap image 3

 

This table lists the amount of space taken up by each layer for the same texture using compression (DXT1).

DDS Components # Bytes
header 128
256-by-64 main image 8192
128-by-32 mipmap image 2048
64-by-16 mipmap image 512
32-by-8 mipmap image 128
16-by-4 mipmap image 32
8-by-2 mipmap image 16
4-by-1 mipmap image 8
2-by-1 mipmap image 8
1-by-1 mipmap image 8

 

This table lists the amount of space taken up by each layer for the same texture using a DXGI compression format (in this case BC3_UNORM) that therefore requires the extended header:

DDS Components # Bytes
header (FourCC set to "DX10") 128
extended header (DXGI format set to DXGI_FORMAT_BC3_UNORM) 20
256-by-64 main image 16384
128-by-32 mipmap image 4096
64-by-16 mipmap image 1024
32-by-8 mipmap image 256
16-by-4 mipmap image 64
8-by-2 mipmap image 32
4-by-1 mipmap image 16
2-by-1 mipmap image 16
1-by-1 mipmap image 16

 

Programming Guide for DDS