1. In a computer graphics system wherein objects are represented by one or more primitives each defined by a plurality of vertices, and wherein said objects are rendered to generate a two dimensional image for display during which coordinates of each vertex of said primitives are subjected to a perspective transformation which yields a perspectively transformed depth coordinate associated with the vertex, a method for mapping a texture function to pixels covered by at least one of said primitives comprising the steps of: associating at least one texture parameter to each vertex of said at least one of said primitives; for each vertex of said at least one of said primitives, determining a perspective factor associated with the given vertex based upon the perspectively transformed depth coordinate associated with the given vertex, applying said perspective factor associated with the given vertex to each texture parameter associated with the given vertex to generate a perspectively transformed texture parameter associated with the given vertex; for each pixel covered by said at least one primitive, for each texture parameter associated with each vertex of said at least one primitive, determining a perspectively transformed texture parameter associated with the given pixel according to perspectively transformed texture parameters associated with each vertex of said at least one of said primitives, determining a perspective factor associated with the given pixel according to said perspective factor associated with each vertex of said at least one of said primitives, generating an approximation of M over said perspective factor associated with the given pixel according to data stored in a look up table, and for each perspectively transformed texture parameter associated with the given pixel, performing an operation on said perspectively transformed texture parameter, said perspective factor and said approximation associated with the given pixel to determine a perspectively correct value of said texture parameter associated with the given pixel.