MirBSD manpage: glShadeModel(3)

GLSHADEMODEL(3G)    UNIX Programmer's Manual     GLSHADEMODEL(3G)


     glShadeModel - select flat or smooth shading


     void glShadeModel( GLenum mode )


     mode  Specifies a symbolic value representing a shading
           technique. Accepted values are GL_FLAT and GL_SMOOTH.
           The initial value is GL_SMOOTH.


     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 seg-
     ment i the computed color of vertex i + 1, its second ver-
     tex. 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 except 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.


     GL_INVALID_ENUM is generated if mode is any value other than

MirBSD #10-current     Printed 2021-12-07                       1

GLSHADEMODEL(3G)    UNIX Programmer's Manual     GLSHADEMODEL(3G)

     GL_INVALID_OPERATION is generated if glShadeModel is exe-
     cuted between the execution of glBegin and the corresponding
     execution of glEnd.


     glGet with argument GL_SHADE_MODEL


     glBegin(3G), glColor(3G), glLight(3G), glLightModel(3G)

MirBSD #10-current     Printed 2021-12-07                       2

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