wkspecularlightingfilter.cikernel

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/*
 * Copyright (C) 2005 Oliver Hunt <[e-mail]>.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 
 */
 
kernel vec4 basic(sampler inputNormalVectors, sampler inputLightVectors, __color inputLightingColor, float inputSurfaceScale, float inputSpecularConstant,
        float inputSpecularExponent, float inputKernelUnitLengthX, float inputKernelUnitLengthY)
{
    vec2 pos = samplerCoord(inputLightVectors);
    vec2 posn = samplerCoord(inputNormalVectors);
    vec3 l = sample(inputLightVectors, pos).xyz;
    vec3 n = sample(inputNormalVectors, posn).xyz;
    vec3 h = l+vec3(0.0, 0.0, 1.0);
    h = normalize(h);
    float nh = inputSpecularConstant*pow((dot(n, h)), inputSpecularExponent);
    vec4 res = inputLightingColor * nh;
    res.a = max(res.r, res.g);
    res.a = max(res.a, res.b);
    return res;
}