GLDEPTHRANGE(3G)GLDEPTHRANGE(3G)NAMEglDepthRange - specify mapping of depth values from normalized device
coordinates to window coordinates
C SPECIFICATION
void glDepthRange( GLclampd near_val,
GLclampd far_val )
delim $$
PARAMETERS
near_val
Specifies the mapping of the near clipping plane to window
coordinates. The initial value is 0.
far_val
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 near_val be less than far_val. Reverse
mappings such as $"near_val" ~=~ 1$, and $"far_val" ~=~ 0$ 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 ALSOglDepthFunc(3G), glPolygonOffset(3G), glViewport(3G)
March 1, 2011
