private void SetMeshMaterial(UWB_Primitive prim, RayTracer_552.RTMaterial mat)
 {
     prim.EnableLighting(true);
     prim.setShadeMode(eShadeMode.smGouraud);
     prim.Material.Emissive = new Vector4(Vector3.Zero, 1f);
     prim.Material.Ambient  = new Vector4(mat.GetAmbientColor, 1f);
     prim.Material.Diffuse  = new Vector4(mat.GetDiffuseColor, 1f);
     prim.Material.Specular = new Vector4(mat.GetSpecularColor, 1f);
     prim.Material.Power    = mat.GetN;
 }