RE: [Algorithms] Mipmap generation
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From: Jon W. <hp...@mi...> - 2003-04-25 16:56:37
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> Is better to generate a mipmap from the previous-level mipmap or from = the > top-level mipmap? I suspect that the former is better for=20 > anti-aliasing and > the latter is better for detail, so it depends on what I'm trying to > achieve, or am I totally out of my depth here? The top-level image has more detail, so if you have a filter=20 function which can take advantage of that (various wide windowed=20 kernels) then it's better to start where you have the detail. If your filter function is just a box filter, there is no difference=20 between using the previous image, or using the top-level image;=20 just work out the math for each pixel and you'll see this is true.=20 (Well, if you get truncation, there is a little bit of difference,=20 and usually you do get a little bit truncation when stuffing the=20 average of four byte values into a byte...) Cheers, / h+ |