1. A method, performed in a processing apparatus, of processing data defining a three-dimensional mesh of planar triangles representing the surface shape of a three-dimensional object, to generate data defining a texture coordinate map comprising a two-dimensional area in which triangles corresponding to the triangles from the mesh are defined, the method comprising: testing the triangles in the mesh to generate a plurality of triangle lists, each triangle list identifying a sequence of connected triangles in the mesh or identifying a single triangle in the mesh, with at least one of the generated triangle lists identifying a sequence of connected triangles; and generating a texture coordinate map by defining a respective triangle in a two-dimensional area for each triangle in the mesh in accordance with the generated triangle lists, such that, for each respective list, the triangles in the list are defined in the two-dimensional area in accordance with the sequence defined by the list.