Definition of the rendering (colour shading) model
TOM_NONE No interpolation, constant shading
(FLAT Shading)
TOM_INTERP_COLOR Linear interpolation of color
(Gouraud Shading)
TOM_FACET Interpolation of color based on
dot products
(Quick Phong Shading)
TOM_VERTEX Interpolation of color based on
normals
(Phong Shading)