147 lines
4.5 KiB
C++
147 lines
4.5 KiB
C++
/*
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This file is part of Mitsuba, a physically based rendering system.
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Copyright (c) 2007-2014 by Wenzel Jakob and others.
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Mitsuba 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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Mitsuba 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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#if !defined(__MITSUBA_RENDER_PHOTON_H_)
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#define __MITSUBA_RENDER_PHOTON_H_
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#include <mitsuba/core/serialization.h>
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#include <mitsuba/core/kdtree.h>
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/**
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* \brief Should Mitsuba use a left-balanced photon map?
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*
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* This saves some memory, but at a noticeable cost in query
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* performance. The default is to build an unbalanced
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* photon map using the sliding midpoint rule.
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*/
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#define MTS_PHOTONMAP_LEFT_BALANCED 0
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MTS_NAMESPACE_BEGIN
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/// Internal data record used by \ref Photon
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struct PhotonData {
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#if defined(SINGLE_PRECISION) && SPECTRUM_SAMPLES == 3
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uint8_t power[4]; //!< Photon power stored in Greg Ward's RGBE format
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#else
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Spectrum power; //!< Accurate spectral photon power representation
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#endif
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uint8_t theta; //!< Discretized photon direction (\a theta component)
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uint8_t phi; //!< Discretized photon direction (\a phi component)
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uint8_t thetaN; //!< Discretized surface normal (\a theta component)
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uint8_t phiN; //!< Discretized surface normal (\a phi component)
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uint16_t depth; //!< Photon depth (number of preceding interactions)
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};
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/** \brief Memory-efficient photon representation for use with
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* \ref PointKDTree
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*
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* \ingroup librender
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* \sa PhotonMap
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*/
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struct MTS_EXPORT_RENDER Photon :
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#if MTS_PHOTONMAP_LEFT_BALANCED == 1
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public LeftBalancedKDNode<Point, PhotonData> {
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#else
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public SimpleKDNode<Point, PhotonData> {
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#endif
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friend class PhotonMap;
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public:
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/// Dummy constructor
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inline Photon() { }
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/// Construct from a photon interaction
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Photon(const Point &pos, const Normal &normal,
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const Vector &dir, const Spectrum &power,
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uint16_t depth);
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/// Unserialize from a binary data stream
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Photon(Stream *stream);
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/// @}
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// ======================================================================
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/// Return the depth (in # of interactions)
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inline int getDepth() const {
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return data.depth;
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}
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/**
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* Convert the photon direction from quantized spherical coordinates
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* to a floating point vector value. Precomputation idea based on
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* Jensen's implementation.
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*/
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inline Vector getDirection() const {
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return Vector(
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m_cosPhi[data.phi] * m_sinTheta[data.theta],
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m_sinPhi[data.phi] * m_sinTheta[data.theta],
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m_cosTheta[data.theta]
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);
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}
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/**
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* Convert the normal direction from quantized spherical coordinates
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* to a floating point vector value.
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*/
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inline Normal getNormal() const {
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return Normal(
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m_cosPhi[data.phiN] * m_sinTheta[data.thetaN],
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m_sinPhi[data.phiN] * m_sinTheta[data.thetaN],
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m_cosTheta[data.thetaN]
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);
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}
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/// Convert the photon power from RGBE to floating point
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inline Spectrum getPower() const {
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#if defined(SINGLE_PRECISION) && SPECTRUM_SAMPLES == 3
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Spectrum result;
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result.fromRGBE(data.power);
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return result;
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#else
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return data.power;
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#endif
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}
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/// Serialize to a binary data stream
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void serialize(Stream *stream) const;
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/// Return a string representation (for debugging)
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std::string toString() const;
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protected:
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// ======================================================================
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/// @{ \name Precomputed lookup tables
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// ======================================================================
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static Float m_cosTheta[256];
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static Float m_sinTheta[256];
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static Float m_cosPhi[256];
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static Float m_sinPhi[256];
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static Float m_expTable[256];
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static bool m_precompTableReady;
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/// @}
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// ======================================================================
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/// Initialize the precomputed lookup tables
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static bool createPrecompTables();
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};
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MTS_NAMESPACE_END
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#endif /* __MITSUBA_RENDER_PHOTON_H_ */
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