1. A method of pairing pixels for texel processing within a programmable graphics processing pipeline to produce an image, comprising: receiving, by a texture unit within the programmable graphics processing pipeline, texture coordinates for the texels mapped to a pixel quad that includes four pixels, wherein each pixel is represented by an anisotropic footprint in texel space and at least one pixel is covered by rasterized geometry; receiving, by the texture unit, major axis alignment information for a major axis of one of the anisotropic footprints; pairing the four pixels of the pixel quad into a first pixel pair and a second pixel pair, wherein the first pixel pair and the second pixel pair each include two pixels of the pixel quad that are aligned with a y axis in pixel space when the major axis alignment information indicates that the major axis of one of the anisotropic footprints in texel space is aligned with an x axis in pixel space; outputting the texture coordinates for the texels for processing in a sequence of packets including a first packet for the first pixel pair and a second packet for the second pixel pair; processing the texels within the programmable graphics processing pipeline to produce filtered results for pixels of the image; and storing the pixels in a memory.