Does it make sense to use own mipmap creation algorithm for OpenGL textures?

Question

I was wondering if the quality of texture mipmaps would be better if I used my own algorithm for pre-generating them, instead of the built-in automatic one. I\'d probably use a

Answer 1

It depends on the kind of assets you display. Lanczos filter gets closer to ideal low-pass filter and the results are noticeable if you compare the mip maps side by side. Most people will mistake aliasing for sharpness - again it depends whether your assets tend to contain high frequencies - I've definitely seen cases where box filter was not a good option. But since the mip map is then linearly interpolated anyway the gain might not be that noticeable. There is another thing to mention - most people use box filter and pass the output as an input into the next stage - in this way you lose both precision and visual energy (although gamma will help this one). If you can come up with code that uses arbitrary filter (mind you that most of them are separable into two passes) you would typically scale the filter kernel itself and produce mip map levels from the base texture, which is a good thing.