'\"
'\" Copyright (c) 1997 Maorong Zou
'\" 
.TH EZ_DefineLight 3 "" EZWGL "EZWGL Functions"
.BS
.SH NAME
EZ_DefineLightSrc, EZ_BindLightSrc \- define light source parameters

.SH SYNOPSIS
.nf
.B #include <EZ.h>
.sp
.BI "EZ_LightSrc *EZ_DefineLightSrc(float *" parameters )
.BI "void EZ_BindLightSrc(int "num ", EZ_LightSrc *" lsrc )

.SH ARGUMENTS
.sp
\fIparameters\fR  Specifies light source properties.
.sp
\fInum\fR Specifies a light source, must be an integer between 0 and 7.
.sp
\fIlsrc\fR Specifies a pre-defined light source.
.sp

.SH DESCRIPTION
.PP
\fBEZ_DefineLightSrc\fR defines a light source based on the
specified parameters. The defined light source can later be
binded to one of the 8 light sources.
.PP
\fIparameters\fR specifies an array of floating point symbols and
values that defines the light source properties.
\fIparameters\fR must contain a sequence of lighting symbols,
each followed by the appropriate number of floating point values. 
The last symbol must be EZ_NULL_F, which is itself not followed by any
values.
.sp
The symbols are:
.in +3
.sp
\fBEZ_POSITION_F\fR specifies the position of the light source, must
followed by 4 floating point numbers that defines the position of the
light source. 
.sp
\fBEZ_AMBIENT_F\fR specifies the ambient color of the light source,
must followed by 4 floats in the range [0.0, 1.0] that specify the
intensity of the RGBA components of the color.
.sp
\fBEZ_DIFFUSE_F\fR specifies the diffuse color of the light source,
must followed by 4 floats in the range [0.0, 1.0] that specify the
intensity of the RGBA components of the color.
.sp
\fBEZ_SPECULAR_F\fR specifies the specular color of the light source,
must followed by 4 floats in the range [0.0, 1.0] that specify the
intensity of the RGBA components of the color.
.sp
\fBEZ_SPOT_DIRECTION_F\fR specifies the spot direction of a spot light
source, must followed by 4 floats that specify the spot direction.
.sp
\fBEZ_SPOT_EXPONENT_F\fR specifies the spot exponent, must followed by
a non-negative floating point number that specifies the spot exponent.
.sp
\fBEZ_SPOT_CUTOFF_F\fR specifies the spot cutoff angle, must followed
by an angle in degrees between 0.0 and 180.0.
.sp
\fBEZ_CONSTANT_ATTENUATION_F\fR specifies the constant attenuation
coefficient, must followed by a floating point number that specifies
the attenuation factor.
.sp
\fBEZ_LINEAR_ATTENUATION_F\fR specifies the linear attenuation
coefficient, must followed by a floating point number that specifies
the attenuation factor.
.sp
\fBEZ_QUADRATIC_ATTENUATION_F\fR specifies the quadratic attenuation
coefficient, must followed by a floating point number that specifies
the attenuation factor.
.in -3
.PP
\fBEZ_BindLightSrc\fR binds the specified pre-defined light source property
to the specified light source.

.SH "SEE ALSO"
EZ_DefineMaterial(3), EZ_DefineLightModel(3), EZ_BindMaterial(3),
EZ_BindLightModel(3)