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/**
* Precomputed Atmospheric Scattering
* Copyright (c) 2008 INRIA
* 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.
* 3. Neither the name of the copyright holders nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "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 COPYRIGHT OWNER 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.
*/
/**
* Author: Eric Bruneton
*/
// computes higher order scattering (line 9 in algorithm 4.1)
uniform float r;
uniform vec4 dhdH;
uniform int layer;
uniform sampler3D deltaJSampler;
#ifdef _VERTEX_
void main() {
gl_Position = gl_Vertex;
}
#endif
#ifdef _GEOMETRY_
#extension GL_EXT_geometry_shader4 : enable
void main() {
gl_Position = gl_PositionIn[0];
gl_Layer = layer;
EmitVertex();
gl_Position = gl_PositionIn[1];
gl_Layer = layer;
EmitVertex();
gl_Position = gl_PositionIn[2];
gl_Layer = layer;
EmitVertex();
EndPrimitive();
}
#endif
#ifdef _FRAGMENT_
vec3 integrand(float r, float mu, float muS, float nu, float t) {
float ri = ieeesqrt(r * r + t * t + 2.0 * r * mu * t);
float mui = (r * mu + t) / ri;
float muSi = (nu * t + muS * r) / ri;
return texture4D(deltaJSampler, ri, mui, muSi, nu).rgb * transmittance(r, mu, t);
}
vec3 inscatter(float r, float mu, float muS, float nu) {
vec3 raymie = vec3(0.0);
float dx = limit(r, mu) / float(INSCATTER_INTEGRAL_SAMPLES);
float xi = 0.0;
vec3 raymiei = integrand(r, mu, muS, nu, 0.0);
for (int i = 1; i <= INSCATTER_INTEGRAL_SAMPLES; ++i) {
float xj = float(i) * dx;
vec3 raymiej = integrand(r, mu, muS, nu, xj);
raymie += (raymiei + raymiej) / 2.0 * dx;
xi = xj;
raymiei = raymiej;
}
return raymie;
}
void main() {
float mu, muS, nu;
getMuMuSNu(r, dhdH, mu, muS, nu);
gl_FragColor.rgb = inscatter(r, mu, muS, nu);
}
#endif
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