Antialiasing Procedural Shaders with Reduction Maps

Both image textures and procedural textures suffer from minification aliasing, however, unlike image textures, there is no good automatic method to anti-alias procedural textures. Given a procedural texture on a surface, we present a method that automatically creates an anti-aliased version of the procedural texture. The new procedural texture maintains the original texture's details, but reduces minification aliasing artifacts. This new algorithm creates a pyramid similar to MIP-Maps to represent the texture. Instead of storing per-texel color, our texture hierarchy stores weighted sums of reflectance functions, allowing a wider range of effects to be anti-aliased. The stored reflectance functions are automatically selected based on an analysis of the different reflectances found over the surface. When the texture is viewed at close range, the original texture is used, but as the texture footprint grows, the algorithm gradually replaces the texture's result with an anti-aliased one.