lshaderange(3G)lshaderange(3G)NAMElshaderange - sets range of color indices used for depth-cueing
C SPECIFICATION
void lshaderange(lowin, highin, znear, zfar)
Colorindex lowin, highin;
long znear, zfar;
PARAMETERS
lowin expects the low-intensity color map index.
highin expects the high-intensity color map index.
znear expects the nearer screen z, to which highin is mapped.
zfar expects the farther screen z, to which lowin is mapped.
DESCRIPTIONlshaderange sets the range of color indices used for depth-cueing. The
screen z range [znear, zfar] is mapped linearly into the color index
range [highin, lowin]. Screen z values nearer than znear map to highin;
screen z values farther than zfar map to lowin.
The valid range for znear and zfar depends on the state of the
GLC_ZRANGEMAP compatibility mode (see glcompat). If it is 0, the valid
range depends on the graphics hardware. When multisample is enabled, and
multisample buffers exist in the current framebuffer configuration in the
current drawmode, the minimum is the value returned by
getgconfig(GC_MS_ZMIN) and the maximum is the value returned by
getgconfig(GC_MS_ZMAX). Otherwise, the minimum is the value returned by
getgconfig(GC_ZMIN) and the maximum is the value returned by
getgconfig(GC_ZMAX). If the state of the GLC_ZRANGEMAP compatibility
mode is 1, the minimum is 0x0 and the maximum is 0x7FFFFF. The default
is lshaderange(0, 7, Zmin, Zmax), where Zmin and Zmax are the values such
that the full range supported by the graphics hardware is used.
Znear and zfar should be chosen to be consistent with the near and far
parameters passed to lsetdepth. If near < far, then znear should be less
than zfar. If near > far, then znear should be greater than zfar. In
either case, the range [near, far] should bound the range [znear, zfar].
SEE ALSO
depthcue, getgdesc, glcompat, lsetdepth
NOTE
When using this routine, you should always explicitly set the
GLC_ZRANGEMAP mode of glcompat because its default is different on
different models.
Page 1
