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/**
* @file lightFuncV.glsl
*
* $LicenseInfo:firstyear=2007&license=viewerlgpl$
* Second Life Viewer Source Code
* Copyright (C) 2007, Linden Research, Inc.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation;
* version 2.1 of the License only.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*
* Linden Research, Inc., 945 Battery Street, San Francisco, CA 94111 USA
* $/LicenseInfo$
*/
float calcDirectionalLight(vec3 n, vec3 l)
{
float a = max(dot(n,normalize(l)),0.0);
return a;
}
float calcPointLightOrSpotLight(vec3 v, vec3 n, vec4 lp, vec3 ln, float la, float is_pointlight)
{
//get light vector
vec3 lv = lp.xyz-v;
//get distance
float d = length(lv);
//normalize light vector
lv *= 1.0/d;
//distance attenuation
float da = clamp(1.0/(la * d), 0.0, 1.0);
// spotlight coefficient.
float spot = max(dot(-ln, lv), is_pointlight);
da *= spot*spot; // GL_SPOT_EXPONENT=2
//angular attenuation
da *= calcDirectionalLight(n, lv);
return da;
}
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