Editing Lightmap (section)

==History==

[[John Carmack]]'s ''[[Quake (video game)|Quake]]'' was the first computer game to use lightmaps to augment [[Scanline rendering|rendering]].<ref>{{Cite web|url=http://www.bluesnews.com/abrash/chap68.shtml|title=Quake's Lighting Model: Surface Caching|last=Abrash|first=Michael|date=|website=Blue's News|archive-url=|archive-date=|accessdate=2015-09-07}}</ref> Before lightmaps were invented, realtime applications relied purely on [[Gouraud shading]] to interpolate vertex lighting for surfaces. This only allowed low frequency lighting information, and could create clipping artifacts close to the camera without perspective-correct interpolation. [[Discontinuity meshing]] was sometimes used especially with [[Radiosity (computer graphics)|radiosity]] solutions to adaptively improve the resolution of vertex lighting information, however the additional cost in primitive setup for realtime rasterization was generally prohibitive. [[Quake (video game)|Quake]]'s software rasterizer used [[surface caching]] to apply lighting calculations in texture space once when polygons initially appear within the [[viewing frustum]] (effectively creating temporary 'lit' versions of the currently visible textures as the viewer negotiated the scene).

As consumer 3d graphics hardware capable of [[multitexturing]], light-mapping became more popular, and engines began to combine light-maps in real time as a secondary [[Blend modes#Multiply|multiply-blend]] texture layer.