warp.cpp

/*
    This file is part of Nori, a simple educational ray tracer
 
    Copyright (c) 2015 by Wenzel Jakob
 
    Nori is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License Version 3
    as published by the Free Software Foundation.
 
    Nori is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
    GNU General Public License for more details.
 
    You should have received a copy of the GNU General Public License
    along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
 
#include <nori/warp.h>
#include <nori/vector.h>
#include <nori/frame.h>
 
NORI_NAMESPACE_BEGIN
 
Vector3f Warp::sampleUniformHemisphere(Sampler *sampler, const Normal3f &pole) {
    // Naive implementation using rejection sampling
    Vector3f v;
    do {
        v.x() = 1.f - 2.f * sampler->next1D();
        v.y() = 1.f - 2.f * sampler->next1D();
        v.z() = 1.f - 2.f * sampler->next1D();
    } while (v.squaredNorm() > 1.f);
 
    if (v.dot(pole) < 0.f)
        v = -v;
    v /= v.norm();
 
    return v;
}
 
Point2f Warp::squareToUniformSquare(const Point2f &sample) {
    return sample;
}
 
float Warp::squareToUniformSquarePdf(const Point2f &sample) {
    return ((sample.array() >= 0).all() && (sample.array() <= 1).all()) ? 1.0f : 0.0f;
}
 
Point2f Warp::squareToUniformDisk(const Point2f &sample) {
    throw NoriException("Warp::squareToUniformDisk() is not yet implemented!");
}
 
float Warp::squareToUniformDiskPdf(const Point2f &p) {
    throw NoriException("Warp::squareToUniformDiskPdf() is not yet implemented!");
}
 
Vector3f Warp::squareToUniformSphereCap(const Point2f &sample, float cosThetaMax) {
    throw NoriException("Warp::squareToUniformSphereCap() is not yet implemented!");
}
 
float Warp::squareToUniformSphereCapPdf(const Vector3f &v, float cosThetaMax) {
    throw NoriException("Warp::squareToUniformSphereCapPdf() is not yet implemented!");
}
 
Vector3f Warp::squareToUniformSphere(const Point2f &sample) {
    throw NoriException("Warp::squareToUniformSphere() is not yet implemented!");
}
 
float Warp::squareToUniformSpherePdf(const Vector3f &v) {
    throw NoriException("Warp::squareToUniformSpherePdf() is not yet implemented!");
}
 
Vector3f Warp::squareToUniformHemisphere(const Point2f &sample) {
    throw NoriException("Warp::squareToUniformHemisphere() is not yet implemented!");
}
 
float Warp::squareToUniformHemispherePdf(const Vector3f &v) {
    throw NoriException("Warp::squareToUniformHemispherePdf() is not yet implemented!");
}
 
Vector3f Warp::squareToCosineHemisphere(const Point2f &sample) {
    throw NoriException("Warp::squareToCosineHemisphere() is not yet implemented!");
}
 
float Warp::squareToCosineHemispherePdf(const Vector3f &v) {
    throw NoriException("Warp::squareToCosineHemispherePdf() is not yet implemented!");
}
 
Vector3f Warp::squareToBeckmann(const Point2f &sample, float alpha) {
    throw NoriException("Warp::squareToBeckmann() is not yet implemented!");
}
 
float Warp::squareToBeckmannPdf(const Vector3f &m, float alpha) {
    throw NoriException("Warp::squareToBeckmannPdf() is not yet implemented!");
}
 
Vector3f Warp::squareToUniformTriangle(const Point2f &sample) {
    float su1 = sqrtf(sample.x());
    float u = 1.f - su1, v = sample.y() * su1;
    return Vector3f(u,v,1.f-u-v);
}
 
NORI_NAMESPACE_END