HP b2600

D
glDepthRange
Chapter 4
103
glDepthRange
glDepthRange: specify mapping of depth values from normalized device coordinates to
window coordinates.
C Specification
void glDepthRange(
GLclampd zNear,
GLclampd zFar)
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 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 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 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