1991-2006
Silicon Graphics, Inc.
glDepthRange
3G

# 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/.