Mathematical Look-ups in Textures

Sometimes it can be a good idea to encode the results of a complex function into a texture and use it as a look-up table instead of performing the calculations in a shader. However, this will only provide a boost in performance if a bottleneck has been identified in the processing of the shader in question, and bandwidth is free to perform the texture lookup. If the function parameters and therefore the texture coordinates in the look-up table vary wildly between adjacent fragments, then cache efficiency will suffer. As a significant amount of work must be saved for this to be an optimisation, profiling should be performed to determine if the results of using look-up tables are acceptable.