Surface caching
Encyclopedia
Surface caching is a computer graphics technique pioneered by John Carmack, first used in the computer game Quake to apply lightmap
s to level geometry. Carmack's technique was to combine lighting information with surface textures in texture-space when primitives became visible (at the appropriate mipmap level), exploiting temporal coherence for those calculations. As hardware capable of blended multi-texture rendering (and later pixel shaders) became more commonplace, the technique became less common, being replaced with screenspace combination of lightmaps in rendering hardware.
Surface caching contributed greatly to the visual quality of Quakes' software rasterized 3d engine on Pentium
microprocessors, which lacked dedicated graphics instructions. .
Surface caching could be considered a precursor to the more recent megatexture
technique in which lighting and surface decals and other procedural texture effects are combined for rich visuals devoid of un-natural repeating artefacts.
Lightmap
A lightmap is a data structure which contains the brightness of surfaces in 3d graphics applications such as video games. Lightmaps are precomputed and used for static objects. Quake was the first computer game to use lightmaps to augment rendering. Before lightmaps were invented, realtime...
s to level geometry. Carmack's technique was to combine lighting information with surface textures in texture-space when primitives became visible (at the appropriate mipmap level), exploiting temporal coherence for those calculations. As hardware capable of blended multi-texture rendering (and later pixel shaders) became more commonplace, the technique became less common, being replaced with screenspace combination of lightmaps in rendering hardware.
Surface caching contributed greatly to the visual quality of Quakes' software rasterized 3d engine on Pentium
Pentium compatible processor
A Pentium compatible processor is a 32-bit processor computer chip which supports the instructions in the IA-32 instruction set that were implemented by the Intel P5 Pentium processor family...
microprocessors, which lacked dedicated graphics instructions. .
Surface caching could be considered a precursor to the more recent megatexture
MegaTexture
MegaTexture refers to a texture allocation technique facilitating the use of a single extremely large texture rather than repeating multiple smaller textures. It is featured in Splash Damage's game Enemy Territory: Quake Wars and was developed by id Software technical director John...
technique in which lighting and surface decals and other procedural texture effects are combined for rich visuals devoid of un-natural repeating artefacts.
External links
- Quake's Lighting Model: Surface Caching - an in-depth explanation by Michael AbrashMichael AbrashMichael Abrash is a technical writer specializing in optimization and 80x86 assembly language programming, a reputation cemented by his 1990 book Zen of Assembly Language Volume 1: Knowledge. The original 8086 processor, the focus of the book, was several generations behind the state of the art by...