photonmapper.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/integrator.h>
#include <nori/sampler.h>
#include <nori/emitter.h>
#include <nori/bsdf.h>
#include <nori/scene.h>
#include <nori/photon.h>
 
NORI_NAMESPACE_BEGIN
 
class PhotonMapper : public Integrator {
public:
    typedef PointKDTree<Photon> PhotonMap;
 
    PhotonMapper(const PropertyList &props) {
        /* Lookup parameters */
        m_photonCount  = props.getInteger("photonCount", 1000000);
        m_photonRadius = props.getFloat("photonRadius", 0.0f /* Default: automatic */);
    }
 
    virtual void preprocess(const Scene *scene) override {
        cout << "Gathering " << m_photonCount << " photons .. ";
        cout.flush();
 
        /* Create a sample generator for the preprocess step */
        Sampler *sampler = static_cast<Sampler *>(
            NoriObjectFactory::createInstance("independent", PropertyList()));
 
        /* Allocate memory for the photon map */
        m_photonMap = std::unique_ptr<PhotonMap>(new PhotonMap());
        m_photonMap->reserve(m_photonCount);
 
        /* Estimate a default photon radius */
        if (m_photonRadius == 0)
            m_photonRadius = scene->getBoundingBox().getExtents().norm() / 500.0f;
 
    
 
        /* How to add a photon?
         * m_photonMap->push_back(Photon(
         *  Point3f(0, 0, 0),  // Position
         *  Vector3f(0, 0, 1), // Direction
         *  Color3f(1, 2, 3)   // Power
         * ));
         */
 
        // put your code to trace photons here
 
        /* Build the photon map */
        m_photonMap->build();
    }
 
    virtual Color3f Li(const Scene *scene, Sampler *sampler, const Ray3f &_ray) const override {
        
        /* How to find photons?
         * std::vector<uint32_t> results;
         * m_photonMap->search(Point3f(0, 0, 0), // lookup position
         *                     m_photonRadius,   // search radius
         *                     results);
         *
         * for (uint32_t i : results) {
         *    const Photon &photon = (*m_photonMap)[i];
         *    cout << "Found photon!" << endl;
         *    cout << " Position  : " << photon.getPosition().toString() << endl;
         *    cout << " Power     : " << photon.getPower().toString() << endl;
         *    cout << " Direction : " << photon.getDirection().toString() << endl;
         * }
         */
 
        // put your code for path tracing with photon gathering here
 
        return Color3f{};
    }
 
    virtual std::string toString() const override {
        return tfm::format(
            "PhotonMapper[\n"
            "  photonCount = %i,\n"
            "  photonRadius = %f\n"
            "]",
            m_photonCount,
            m_photonRadius
        );
    }
private:
    /* 
     * Important: m_photonCount is the total number of photons deposited in the photon map,
     * NOT the number of emitted photons. You will need to keep track of those yourself.
     */ 
    int m_photonCount;
    float m_photonRadius;
    std::unique_ptr<PhotonMap> m_photonMap;
};
 
NORI_REGISTER_CLASS(PhotonMapper, "photonmapper");
NORI_NAMESPACE_END