101 lines
3.2 KiB
GLSL
101 lines
3.2 KiB
GLSL
/**
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* Precomputed Atmospheric Scattering
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* Copyright (c) 2008 INRIA
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. Neither the name of the copyright holders nor the names of its
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* contributors may be used to endorse or promote products derived from
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* this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
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* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
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* THE POSSIBILITY OF SUCH DAMAGE.
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*/
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/**
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* Author: Eric Bruneton
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*/
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// computes higher order scattering (line 9 in algorithm 4.1)
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uniform float r;
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uniform vec4 dhdH;
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uniform int layer;
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uniform sampler3D deltaJSampler;
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#ifdef _VERTEX_
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void main() {
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gl_Position = gl_Vertex;
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}
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#endif
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#ifdef _GEOMETRY_
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#extension GL_EXT_geometry_shader4 : enable
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void main() {
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gl_Position = gl_PositionIn[0];
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gl_Layer = layer;
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EmitVertex();
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gl_Position = gl_PositionIn[1];
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gl_Layer = layer;
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EmitVertex();
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gl_Position = gl_PositionIn[2];
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gl_Layer = layer;
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EmitVertex();
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EndPrimitive();
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}
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#endif
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#ifdef _FRAGMENT_
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vec3 integrand(float r, float mu, float muS, float nu, float t) {
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float ri = sqrt(r * r + t * t + 2.0 * r * mu * t);
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float mui = (r * mu + t) / ri;
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float muSi = (nu * t + muS * r) / ri;
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return texture4D(deltaJSampler, ri, mui, muSi, nu).rgb * transmittance(r, mu, t);
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}
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vec3 inscatter(float r, float mu, float muS, float nu) {
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vec3 raymie = vec3(0.0);
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float dx = limit(r, mu) / float(INSCATTER_INTEGRAL_SAMPLES);
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float xi = 0.0;
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vec3 raymiei = integrand(r, mu, muS, nu, 0.0);
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for (int i = 1; i <= INSCATTER_INTEGRAL_SAMPLES; ++i) {
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float xj = float(i) * dx;
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vec3 raymiej = integrand(r, mu, muS, nu, xj);
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raymie += (raymiei + raymiej) / 2.0 * dx;
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xi = xj;
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raymiei = raymiej;
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}
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return raymie;
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}
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void main() {
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float mu, muS, nu;
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getMuMuSNu(r, dhdH, mu, muS, nu);
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gl_FragColor.rgb = inscatter(r, mu, muS, nu);
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}
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#endif
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