ericwa
commented
1 month ago A few ideas:
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a special texture name like
lightgrid_lowdensity(or a func_group key) that would calculate lighting at the center of the brush, and any lightgrid sample points falling inside that brush would use the already calculated light value from the center, rather than being calculated per grid point.Note that we don't have a way of storing these at a lower density in the output BSPX lump, so the size of the output lump wouldn't get any smaller, but it would be faster to compute lighting. (having the LIGHTGRID_OCTREE lump able to switch to a lower density for large outdoor areas was on my feature wishlist but it didn't happen, so if we ever implemented that it'd need to be a new lump).
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We do have a concept of a lightgrid point being "occluded" - if it falls inside the void (CONTENTS_SOLID), we don't calculate lighting for it, and the octree lump can avoid writing out areas that are completely occluded. So we could expose this to the mapper, with either brushes to mark areas as "occluded" that normally wouldn't be, or like you were proposing an opt-in version where everything is occluded except the areas marked with
_lightgridtextures.My only worry with this is, I don't know what renderers will do if a model goes into this area. I guess it would be "undefined lighting" so the engine could do whatever. Do we really want to expose this as a mapper feature since it sort of works against the initial goal of having lightgrid? Are there large areas where you definitely won't ever need to sample a lighting value?
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it's possible the lighting calculation for the lightgrid could be optimized further, it was sort of done in a rush.
any thoughts @Paril ?
BraXi
With current approach lightgrid points are calculated for entire mins/maxs of a worldmodel which often results in lightgrid points being computed for large out of player reach areas, this also does take noticeably more time than calculating lightmaps for large outdoor areas.
My idea is to introduce
_lightgridtextured brushes that would cover playable areas, grid points within such brushes would be properly calculated, leaving outside grid points fullbright or dark and/or not computed at all to save on compilation times.This should be entirely optional and enabled only by a switch or use of
_lightgridtexture in a map.