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Gammastrahler

How could i improve image quality and precision?

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Hi, i have written two versions of my radiosity processor (progressive refinement). the one creates lightmap textures and the other version uses per-vertex radiositys. and the same scene looks far better and more precise with a very high - resolution mesh (using vertex radiositys) than using lightmaps (even at very high resolutions). is there a way to get the same quality with lightmaps? thanks Gammastrahler

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There are many ways to generate lightmaps; how exactly does your radiosity engine create them? Is each lightmap texture a constant resolution or do you attempt to scale textures for different sized surfaces to get a best-fit? What sort of quality problems are you having? Could you possibly post a comparison of the two to show what kind of artifacts you are looking to eliminate?

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Well, one consideration is whether the high resolution mesh actually changes the geometry, or if it just adds more vertices. Remember that if you're actually adding extra detail, no amount of lightmapping can add that unless you take normal maps into account as well.

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Quote:
Original post by ApochPiQ
There are many ways to generate lightmaps; how exactly does your radiosity engine create them? Is each lightmap texture a constant resolution or do you attempt to scale textures for different sized surfaces to get a best-fit? What sort of quality problems are you having? Could you possibly post a comparison of the two to show what kind of artifacts you are looking to eliminate?


Currently i cannot post any images.

I choose different lightmap resolutions for different sized surfaces, but the lightmaps are still the same width as height to keep it simple. my idea was to create one big lightmap (say 2048*2048) and then use it as a storage for many surfaces, which i then access via different texture coordinates. but this failed.

the sort of quality problems i have is, i think, due to texture interpolation errors. gradients are´t sharp enough, shadows are too blurry (my per-vertex renderer creates soft shadows as i expect, not too hard and not to soft).

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This also sounds to me like texture resolution problems. Generally if the ratio of lightmap texels to on-screen pixels does not average to near 1:1 or better, the lightmap will tend to look incorrect. This can of course be fixed by increasing the resolution and number of lightmap textures per surface (expensive) or by fudging out the detail on the lightmaps with more complex interpolation schemes.

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Here is an image of the high-resolution mesh image. although each of the primitives have the same color (actually not per-vertex but per-polygon), you can see the fine details around the light sources, which is not possible with my light map renderer.

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