OpenSpace/modules/base/shaders/deltaS_sup_calc_fs.glsl

/*****************************************************************************************
 *                                                                                       *
 * OpenSpace                                                                             *
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 * Copyright (c) 2014-2016                                                               *
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#include "atmosphere_common.glsl"
#include "fragment.glsl"
#include "PowerScaling/powerScalingMath.hglsl"

layout(location = 1) out vec4 renderTarget1;

uniform int layer;

uniform sampler3D deltaSTexture;

// Rayleigh phase
float phaseFunctionR(const float mu) {
    return (3.0 / (16.0 * M_PI)) * (1.0 + mu * mu);
}

Fragment getFragment() {
    float x = gl_FragCoord.x - 0.5;
    float y = gl_FragCoord.y - 0.5;

    float nu = -1.0 + floor(x / float(RES_MU_S)) / (float(RES_NU) - 1.0) * 2.0;
    vec3 uvw = vec3(gl_FragCoord.xy, float(layer) + 0.5) / vec3(ivec3(RES_MU_S * RES_NU, RES_MU, RES_R));

    renderTarget1 = vec4(texture(deltaSTexture, uvw).rgb / phaseFunctionR(nu), 1.0);
    
    Fragment frag;
    frag.color = vec4(1.0);
    frag.depth = 1.0;
    
    return frag;
}