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by chipsy 4862 days ago
I'm referring more specifically to mipmaps. They let you cheat when downsampling.
1 comments

Well, yes and no. Mipmaps just make the process faster for a given level of quality by making the resampling ratios closer to 1.0. The closer the ratio gets to 1.0, the fewer filter coefficients you need.

The same thing is done in audio. If you want to upsample 64x, you can do it faster by upsampling 8x twice. Since the signal given to the second upsampler is already bandlimited, the filter can have a much longer falloff and use fewer coefficients.

This is exactly why you want to use a nice filter create the mipmapms but it's okay to use a simple bilinear filter for the final render.

(So what I'm saying is that you can also use mipmaps for upsampling, but nobody likes the storage requirements.)