73 lines
2.8 KiB
C++
73 lines
2.8 KiB
C++
/*
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This file is part of Nori, a simple educational ray tracer
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Copyright (c) 2015 by Wenzel Jakob
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Nori is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License Version 3
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as published by the Free Software Foundation.
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Nori is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#pragma once
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#include <nori/common.h>
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#include <nori/sampler.h>
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NORI_NAMESPACE_BEGIN
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/// A collection of useful warping functions for importance sampling
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class Warp {
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public:
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/// Dummy warping function: takes uniformly distributed points in a square and just returns them
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static Point2f squareToUniformSquare(const Point2f &sample);
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/// Probability density of \ref squareToUniformSquare()
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static float squareToUniformSquarePdf(const Point2f &p);
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/// Sample a 2D tent distribution
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static Point2f squareToTent(const Point2f &sample);
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/// Probability density of \ref squareToTent()
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static float squareToTentPdf(const Point2f &p);
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/// Uniformly sample a vector on a 2D disk with radius 1, centered around the origin
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static Point2f squareToUniformDisk(const Point2f &sample);
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/// Probability density of \ref squareToUniformDisk()
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static float squareToUniformDiskPdf(const Point2f &p);
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/// Uniformly sample a vector on the unit sphere with respect to solid angles
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static Vector3f squareToUniformSphere(const Point2f &sample);
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/// Probability density of \ref squareToUniformSphere()
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static float squareToUniformSpherePdf(const Vector3f &v);
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/// Uniformly sample a vector on the unit hemisphere around the pole (0,0,1) with respect to solid angles
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static Vector3f squareToUniformHemisphere(const Point2f &sample);
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/// Probability density of \ref squareToUniformHemisphere()
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static float squareToUniformHemispherePdf(const Vector3f &v);
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/// Uniformly sample a vector on the unit hemisphere around the pole (0,0,1) with respect to projected solid angles
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static Vector3f squareToCosineHemisphere(const Point2f &sample);
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/// Probability density of \ref squareToCosineHemisphere()
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static float squareToCosineHemispherePdf(const Vector3f &v);
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/// Warp a uniformly distributed square sample to a Beckmann distribution * cosine for the given 'alpha' parameter
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static Vector3f squareToBeckmann(const Point2f &sample, float alpha);
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/// Probability density of \ref squareToBeckmann()
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static float squareToBeckmannPdf(const Vector3f &m, float alpha);
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};
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NORI_NAMESPACE_END
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