PARAMETERS
       mode  Specifies  a symbolic value representing a shading technique.  Ac‐
             cepted values are GL_FLAT and GL_SMOOTH.   The  initial  value  is
             GL_SMOOTH.

DESCRIPTION
       GL  primitives  can have either flat or smooth shading.  Smooth shading,
       the default, causes the computed colors of vertices to  be  interpolated
       as  the primitive is rasterized, typically assigning different colors to
       each resulting pixel fragment.  Flat shading selects the computed  color
       of  just  one vertex and assigns it to all the pixel fragments generated
       by rasterizing a single primitive.  In either case, the  computed  color
       of  a  vertex is the result of lighting if lighting is enabled, or it is
       the current color at the time the vertex was specified  if  lighting  is
       disabled.

       Flat and smooth shading are indistinguishable for points.  Starting when
       glBegin is issued and counting vertices and primitives from  1,  the  GL
       gives  each flat-shaded line segment i the computed color of vertex i+1,
       its second vertex.  Counting similarly from 1, the GL gives  each  flat-
       shaded  polygon the computed color of the vertex listed in the following
       table.  This is the last vertex to specify the polygon in all cases  ex‐
       cept  single  polygons, where the first vertex specifies the flat-shaded
       color.

                         ─────────────────────────────────────
                         Primitive Type of Polygon i   Vertex
                         ─────────────────────────────────────
                         Single polygon (i≡1)            1
                         Triangle strip                 i+2
                         Triangle fan                   i+2
                         Independent triangle            3i
                         Quad strip                     2i+2
                         Independent quad                4i
                         ─────────────────────────────────────

       Flat and smooth shading are specified by glShadeModel with mode  set  to
       GL_FLAT and GL_SMOOTH, respectively.

ERRORS
       GL_INVALID_ENUM  is generated if mode is any value other than GL_FLAT or
       GL_SMOOTH.

       GL_INVALID_OPERATION is generated if glShadeModel  is  executed  between
       the execution of glBegin and the corresponding execution of glEnd.

ASSOCIATED GETS
       glGet with argument GL_SHADE_MODEL

SEE ALSO
       glBegin, glColor, glLight, glLightModel