16. How To Tutorial # 4: How to change the global shading level

The global shading level is set with the Nt_SHADING option of the command. See the Nt_SHADING option in for further information. Using Nt_OFF will cause no shading to be performed, Nt_FLAT will perform one shading calculation per polygon, Nt_GOURAUD will perform one shading calculation per vertex and Nt_SMOOTH will perform one shading calculation per pixel; The Nt_SMOOTH shading mode is required if texture mapping or shadow casting is desired.

The following snippet of C code shows how to set the different shading modes:

shading_levels_example()
{
	Ni_Option(Nt_SHADING, Nt_OFF,     Nt_CMDEND);

	Ni_Option(Nt_SHADING, Nt_FLAT,    Nt_CMDEND);

	Ni_Option(Nt_SHADING, Nt_GOURAUD, Nt_CMDEND);

	Ni_Option(Nt_SHADING, Nt_SMOOTH,  Nt_CMDEND);
}