Techniques and tools for rendering procedural graphics are described. For example, an architecture is provided which allows evaluation of geometric, transform, texture, and shading procedures locally for a given set of procedure parameter values. This evaluation is performed in parallel for different parameter values on a single-instruction, multiple-data array to allow parallel processing of a procedure set. In another example, a sampling controller is described which selects sets of parameter points for evaluation based on information in tag maps, rate maps, and parameter maps.