From: Allan Schaffer (allan++at++sgi.com)
Date: 02/14/2000 21:24:13
On Feb 14, 8:58pm, YoungJun Kim wrote:
> I'm trying to implement spotlight in Performer.
>
> I want to know the varialbles which are in setSpotCone(float a, float b)
> and setSpotDir(float x, float y, float z). In additon, how to use it in
> Performer.
Ultimately they're used for the GL_SPOT_DIRECTION, GL_SPOT_EXPONENT,
and GL_SPOT_CUTOFF tokens in a glLight call -- see the glLight() man
page for their usage.
These particular functions (setSpotCone, setSpotDir) turn out to be
documented in the pfLight manpage; a pfLightSource is essentially a
pfNode (a libpf object) that contains a pfLight (a libpr object).
pfLight::setSpotDir specifies the direction in which a spot
light source emits its light. It receives three floating point
values, x, y, and z, specifying the x, y, and z direction
vectors. pfLight::getSpotDir copies the x, y, and z direction
vectors into the parameters x, y, and z.
pfLight::setSpotCone specifies the exponent and spread of the
spot light cone, and receives two floating point values, f1 and
f2, to set the exponent for the intensity, and the spread of the
cone, respectively. pfLight::getSpotCone copies the current
exponent and spread of the cone into the parameters f1 and f2.
Allan
-- Allan Schaffer allan++at++sgi.com Silicon Graphics http://reality.sgi.com/allan
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