one big lightmap or many small ones?

Graphics and GPU Programming Programming

Started by amish1234 October 22, 2003 01:41 AM

0 comments, last by amish1234 20 years, 5 months ago

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October 22, 2003 01:41 AM

I want to precalculate the lighting for my levels and store it in a lightmap. When I''m rendering, only part of the lightmap will get used, because only part of the level can be seen, and I''ll obviously use occlusion culling. So, since only part of the lightmap is used at a time, would it make any performance difference if I had one huge lightmap or many small ones?

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Impossible

134

October 22, 2003 02:12 AM

In order to reduce batches and state changes using one big lightmap would be the way to go. You can pretty easily group large chunks of geometry that all use the same lightmap, even if all of the chunk isn''t being drawn you only have to worry about a single lightmap for that group, which reduces state changes and possibly batches. Using a few large lightmaps is probably the best way to do. If you use a lot of smaller lightmaps you''ll have to break up your geometry into lots of small chunks, which isn''t great for rendering.