Methods, systems, and devices are disclosed for preparing to prefetch memory in 3D graphical shader programs. Based on the memory addresses of texels from a texture map that were previously read, a memory address of a to-be-read texel is estimated by using a first-order derivative of the memory address with respect to pixel distance. The estimated memory address is then prefetched for use when the pixel corresponding to the texel is rendered. Whether or not to perform the estimation of the texel memory address can be determined by whether the corresponding pixels are on the same, flat facet on a 3D model. Multiple directions on the facet can be used for memory address estimation as well as higher-order derivatives.