A method for a computer system includes determining first shading results associated with a geometric object in response to first shading computations and first shading data associated with the geometric object and associated with both a first scene and a second scene, determining second shading results associated with the geometric object in response to second shading computations and second shading data associated with the geometric object, and determining first combined shading results associated with the geometric object in response to the first shading results and to the second shading results, wherein the first combined shading results is associated with the second scene, wherein a second combined shading results is associated with the geometric object, wherein the second combined shading results is associated with the first scene, and wherein the second combined shading results is not determined in response to the second shading results.