1. A non-transitory computer-readable medium storing instructions that, when executed by a processor, cause the processor to implement: a vertex shader having an output for providing output data generated for a vertex in a mesh; and a fragment shader having an input for receiving input data corresponding to the output data from the vertex shader, wherein the fragment shader can determine, based on the input data, original values associated with each vertex prior to the vertex being processed by the vertex shader, each vertex defining a primitive that contains a fragment being processed by the fragment shader.