NAME
glDepthRange
- specify mapping of depth values from normalized device coordinates to window coordinates
C SPECIFICATION
void ggllDDeepptthhRRaannggee(
GLclampd _n_e_a_r___v_a_l,
GLclampd _f_a_r___v_a_l )
delim $$
PARAMETERS
-
_n_e_a_r___v_a_l
-
Specifies the mapping of the near clipping plane to window coordinates.
The initial value is 0.
-
_f_a_r___v_a_l
-
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.
ggllDDeepptthhRRaannggee 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 ggllDDeepptthhRRaannggee 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 _n_e_a_r___v_a_l be less than _f_a_r___v_a_l.
Reverse mappings such as $"near_val" ~=~ 1$, and $"far_val" ~=~ 0$
are acceptable.
ERRORS
GGLL__IINNVVAALLIIDD__OOPPEERRAATTIIOONN is generated if ggllDDeepptthhRRaannggee
is executed between the execution of ggllBBeeggiinn
and the corresponding execution of ggllEEnndd.
ASSOCIATED GETS
ggllGGeett with argument GGLL__DDEEPPTTHH__RRAANNGGEE
SEE ALSO
ggllDDeepptthhFFuunncc((33GG)),
ggllPPoollyyggoonnOOffffsseett((33GG)),
ggllVViieewwppoorrtt((33GG))