GL_TEXTURE_3D - mipmaps dimensions

Question

When I load a GL_TEXTURE_2D (512x256) mipmaps are defined this way:

• level 0: 512 x 256
• level 1: 256 x 128
• level 2: 128 x 64
• level 3: 64 x 32
• level 4: 32 x 16
• level 5: 16 x 8
• level 6: 8 x 4
• level 7: 4 x 2
• level 8: 2 x 1
• level 9: 1 x 1

I can load all mipmaps manually using glTexImage2D. How mipmaps are defined for GL_TEXTURE_3D, for example (512 x 256 x 4) ?

Answer 1

They are defined in exactly the same way as a 2D texture: take each dimension and divide by 2 (rounded down), and keep going until all dimensions are 1.