96 lines
2.7 KiB
Plaintext
96 lines
2.7 KiB
Plaintext
/*
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* Copyright 2011-2013 Blender Foundation
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#include "stdosl.h"
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shader node_principled_volume(
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color Color = color(0.5, 0.5, 0.5),
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float Density = 1.0,
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float Anisotropy = 0.0,
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color AbsorptionColor = color(0.0, 0.0, 0.0),
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float EmissionStrength = 0.0,
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color EmissionColor = color(1.0, 1.0, 1.0),
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float BlackbodyIntensity = 0.0,
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color BlackbodyTint = color(1.0, 1.0, 1.0),
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float Temperature = 1500.0,
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string DensityAttribute = "geom:density",
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string ColorAttribute = "geom:color",
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string TemperatureAttribute = "geom:temperature",
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output closure color Volume = 0)
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{
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/* Compute density. */
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float primitive_density = 1.0;
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float density = max(Density, 0.0);
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if(density > 1e-5) {
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if(getattribute(DensityAttribute, primitive_density)) {
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density = max(density * primitive_density, 0.0);
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}
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}
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if(density > 1e-5) {
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/* Compute scattering color. */
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color scatter_color = Color;
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color primitive_color;
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if(getattribute(ColorAttribute, primitive_color)) {
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scatter_color *= primitive_color;
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}
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/* Add scattering and absorption closures. */
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color scatter_coeff = scatter_color;
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color absorption_color = sqrt(max(AbsorptionColor, 0.0));
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color absorption_coeff = max(1.0 - scatter_color, 0.0) * max(1.0 - absorption_color, 0.0);
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Volume = scatter_coeff * density * henyey_greenstein(Anisotropy) +
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absorption_coeff * density * absorption();
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}
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/* Compute emission. */
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float emission_strength = max(EmissionStrength, 0.0);
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float blackbody_intensity = BlackbodyIntensity;
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if(emission_strength > 1e-5) {
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Volume += emission_strength * EmissionColor * emission();
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}
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if(blackbody_intensity > 1e-3) {
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float T = Temperature;
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/* Add temperature from attribute if available. */
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float temperature;
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if(getattribute(TemperatureAttribute, temperature)) {
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T *= max(temperature, 0.0);
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}
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T = max(T, 0.0);
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/* Stefan-Boltzman law. */
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float T4 = (T * T) * (T * T);
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float sigma = 5.670373e-8 * 1e-6 / M_PI;
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float intensity = sigma * mix(1.0, T4, blackbody_intensity);
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if(intensity > 1e-5) {
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color bb = blackbody(T);
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float l = luminance(bb);
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if(l != 0.0) {
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bb *= BlackbodyTint * intensity / l;
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Volume += bb * emission();
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}
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}
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}
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}
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