GLDEPTHRANGE(3G)

NAME
glDepthRange - specify mapping of depth values from normalized device coordinates to window coordinates

C SPECIFICATION

void glDepthRange(GLclampd nearVal, GLclampd farVal);

PARAMETERS

nearVal
    Specifies the mapping of the near clipping plane to window coordinates. The initial value is 0.

farVal
    Specifies the mapping of the far clipping plane to window coordinates. The initial value is 1.

DESCRIPTION

After clipping and division by w, depth coordinates range from -1 to 1, corresponding to the near and far clipping planes. glDepthRange specifies a linear mapping of the normalized depth coordinates in this range to window depth coordinates. Regardless of the actual depth buffer implementation, window coordinate depth values are treated as though they range from 0 through 1 (like color components). Thus, the values accepted by glDepthRange are both clamped to this range before they are accepted.

The setting of (0,1) maps the near plane to 0 and the far plane to 1. With this mapping, the depth buffer range is fully utilized.

NOTES

It is not necessary that nearVal be less than farVal. Reverse mappings such as nearVal = 1, and farVal = 0 are acceptable.

ERRORS

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

ASSOCIATED GETS

glGet() with argument GL_DEPTH_RANGE

SEE ALSO

glDepthFunc(), glPolygonOffset(), glViewport()

COPYRIGHT

Copyright © 1991-2006 Silicon Graphics, Inc. This document is licensed under the SGI Free Software B License. For details, see http://oss.sgi.com/projects/FreeB/.