NAME    [Toc]    [Back]

       glPolygonOffset  -  set the scale and units used to calculate
 depth values

SYNOPSIS    [Toc]    [Back]

       void glPolygonOffset(
               GLfloat factor,
               GLfloat units );

PARAMETERS    [Toc]    [Back]

       Specifies a scale factor that is used to create a variable
       depth  offset  for  each polygon.  The initial value is 0.
       Is multiplied by an implementation-specific value to  create
 a constant depth offset. The initial value is 0.

DESCRIPTION    [Toc]    [Back]

       When  GL_POLYGON_OFFSET_FILL,  GL_POLYGON_OFFSET_LINE,  or
       GL_POLYGON_OFFSET_POINT is enabled, each fragment's  depth
       value  will  be  offset  after it is interpolated from the
       depth values of the appropriate vertices. The value of the
       offset  is factor * DZ + r * units, where DZ is a measurement
 of the change in depth relative to the screen area of
       the  polygon,  and r is the smallest value that is guaranteed
 to produce a resolvable offset for a given  implementation.
  The offset is added before the depth test is performed
 and before the value  is  written  into  the  depth
       buffer.

       glPolygonOffset()  is  useful  for  rendering  hidden-line
       images, for applying decals to surfaces, and for rendering
       solids with highlighted edges.

NOTES    [Toc]    [Back]

       glPolygonOffset()  is  available only if the GL version is
       1.1 or greater.

       glPolygonOffset()  has  no  effect  on  depth  coordinates
       placed in the feedback buffer.

       glPolygonOffset() has no effect on selection.

ERRORS    [Toc]    [Back]

       GL_INVALID_OPERATION  is generated if glPolygonOffset() is
       executed between the execution of glBegin() and the corresponding
 execution of glEnd().

ASSOCIATED GETS    [Toc]    [Back]

       glIsEnabled()    with   argument   GL_POLYGON_OFFSET_FILL,
       GL_POLYGON_OFFSET_LINE, or GL_POLYGON_OFFSET_POINT.

       glGet() with argument GL_POLYGON_OFFSET_FACTOR or GL_POLYGON_OFFSET_UNITS.

SEE ALSO    [Toc]    [Back]

       glDepthFunc(3), glEnable(3), glGet(3), glIsEnabled(3)



                                              glPolygonOffset(3G)