1. A method comprising: receiving a base primitive in a graphics processor, the base primitive comprising a first plurality of vertices; determining whether at least one of the vertices of the base primitive can be culled prior to tessellation the determination based on an evaluation of visibility data associated with the first plurality of vertices; culling the base primitive prior to tessellation if the visibility data indicates that all of the vertices of the base primitive are invisible; providing tessellation factors to tessellate the base primitive only if one or more of the first plurality of vertices of the base primitive cannot be culled; tessellating the first representation of the base primitive using the tessellation factors to generate a set of tessellated primitives with a second set of vertices; performing vertex shading operations on the second set of vertices by, at least in part, executing a set of vertex shader instructions to generate vertex-shaded vertices for the tessellated primitives; generating one or more bounding boxes for the tessellated primitives; subjecting the bounding volumes to a culling process to cull one or more of the tessellated primitives contained in the bounding volumes; performing fragment shading on portions of the tessellated primitives which have not been culled to produce a depiction for computer display; and displaying the depiction on a computer display.