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DDS Volume Texture Example

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For a volume texture, use the DDSCAPS_COMPLEX, DDSCAPS2_VOLUME, and DDSD_DEPTH flags, and set dwDepth. A volume texture is an extension of a standard texture for Direct3D 9; a volume texture can be defined with or without mipmaps.

For volumes without mipmaps, each depth slice is written to the file in order. If mipmaps are included, all depth slices for a given mipmap level are written together, with each level containing half as many slices as the previous level with a minimum of 1.

For example, a 64-by-64-by-4 volume map using a pixel format of R8G8B8 (3 bytes per pixel) with all mipmap levels would contain the following:

DDS Components # Bytes
header 128 bytes
64-by-64 slice 1 of 4 main image. 12288 bytes
64-by-64 slice 2 of 4 main image. 12288 bytes
64-by-64 slice 3 of 4 main image. 12288 bytes
64-by-64 slice 4 of 4 main image. 12288 bytes
32-by-32 slice 1 of 2 mipmap image. 3072 bytes
32-by-32 slice 2 of 2 mipmap image. 3072 bytes
16-by-16 slice 1 of 1 mipmap image. 768 bytes
8-by-8 slice 1 of 1 mipmap image. 192 bytes
4-by-4 slice 1 of 1 mipmap image. 48 bytes
2-by-2 slice 1 of 1 mipmap image. 12 bytes
1-by-1 slice 1 of 1 mipmap image. 3 bytes

 

Note that the smallest mipmap level is only 3 bytes because the bitcount is 24 and there is no added compression at this level.

Support for volume textures was added in DirectX 8.

Programming Guide for DDS