Editing Shading (section)

=====Gouraud shading=====
# Determine the normal at each polygon vertex.
# Apply an [[illumination model]] to each vertex to calculate the light intensity from the vertex normal.
# Interpolate the vertex intensities using [[bilinear interpolation]] over the surface polygon.

Problems:
* Due to lighting being computed only at vertices, the inaccuracies (especially of specular highlights on large triangles) can become too apparent.  
* T-junctions with adjoining polygons can sometimes result in visual anomalies. In general, T-junctions should be avoided.