GLDEPTHRANGE() MachTen Programmer’s Manual GLDEPTHRANGE()

NAME
glDepthRange - specify mapping of depth values from nor-
malized device coordinates to window coordinates

C SPECIFICATION
void glDepthRange( GLclampd zNear,
GLclampd zFar )

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

zFar 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 imple-
mentation, window coordinate depth values are treated as
though they range from 0 through 1 (like color compo-
nents). 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 zNear be less than zFar. Reverse
mappings such as $"zNear" = 1$, and $"zFar" = 0$ are
acceptable.

ERRORS
GL_INVALID_OPERATION is generated if glDepthRange is exe-
cuted between the execution of glBegin and the correspond-
ing execution of glEnd.

ASSOCIATED GETS
glGet with argument GL_DEPTH_RANGE

SEE ALSO
glDepthFunc, glPolygonOffset, glViewport

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