MirOS Manual: glFrontFace(3)

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


     glFrontFace - define front- and back-facing polygons


     void glFrontFace( GLenum mode )


     mode  Specifies the orientation of front-facing polygons.
           GL_CW and GL_CCW are accepted. The initial value is


     In a scene composed entirely of opaque closed surfaces,
     back-facing polygons are never visible. Eliminating these
     invisible polygons has the obvious benefit of speeding up
     the rendering of the image. To enable and disable elimina-
     tion of back-facing polygons, call glEnable and glDisable
     with argument GL_CULL_FACE.

     The projection of a polygon to window coordinates is said to
     have clockwise winding if an imaginary object following the
     path from its first vertex, its second vertex, and so on, to
     its last vertex, and finally back to its first vertex, moves
     in a clockwise direction about the interior of the polygon.
     The polygon's winding is said to be counterclockwise if the
     imaginary object following the same path moves in a counter-
     clockwise direction about the interior of the polygon.
     glFrontFace specifies whether polygons with clockwise wind-
     ing in window coordinates, or counterclockwise winding in
     window coordinates, are taken to be front-facing. Passing
     GL_CCW to mode selects counterclockwise polygons as front-
     facing; GL_CW selects clockwise polygons as front-facing. By
     default, counterclockwise polygons are taken to be front-


     GL_INVALID_ENUM is generated if mode is not an accepted

     GL_INVALID_OPERATION is generated if glFrontFace is executed
     between the execution of glBegin and the corresponding exe-
     cution of glEnd.


     glGet with argument GL_FRONT_FACE


     glCullFace(3G), glLightModel(3G)

MirOS BSD #10-current  Printed 03.04.2017                       1

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