glDepthRange
NAME
glDepthRange -- specify the mapping of z values from normalized
device coordinates to window coordinates
C SPECIFICATION
void glDepthRange(GLclampd near,
GLclampd far)
PARAMETERS
- near
-
Specifies the mapping of the near clipping plane to window coordinates.
The default value is 0.
- far
-
Specifies the mapping of the far clipping plane to window coordinates.
The default value is 1.
DESCRIPTION
After clipping and division by w, z coordinates range from -1.0
to 1.0, corresponding to the near and far clipping planes. glDepthRange
specifies a linear mapping of the normalized z coordinates in this range
to window z coordinates. Regardless of the actual depth buffer
implementation, window coordinate depth values are treated as though they range
from 0.0 through 1.0 (like color components). Thus, the values accepted by
glDepthRange are both clamped to this range before they are accepted.
The default mapping 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 near be less than far. Reverse mappings
such as 1, 0 are acceptable.
ERRORS
GL_INVALID_OPERATION is generated if glDepthRange is called
between a call to glBegin and the
corresponding call to glEnd.
ASSOCIATED GETS
glGet with argument
GL_DEPTH_RANGE
SEE ALSO
glDepthFunc,
glViewport
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© 1995 Uwe Behrens. All rights reserved.