Интерактивная система просмотра системных руководств (man-ов)
glDepthRange (3)
>> glDepthRange (3) ( Разные man: Библиотечные вызовы )
NAME
glDepthRange
- 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.
