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GLSHADEMODEL()							GLSHADEMODEL()

NAME
       glShadeModel - select flat or smooth shading

C SPECIFICATION
       void glShadeModel( GLenum mode )

       delim $$

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  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	    |  $ 3 i$	|
		     |Quad strip		    | $2 i + 2$	|
		     |Independent quad		    |  $ 4 i $	|
		     +------------------------------+-----------+
       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

								GLSHADEMODEL()

NAME | C SPECIFICATION | PARAMETERS | DESCRIPTION | ERRORS | ASSOCIATED GETS | SEE ALSO

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