photon.h

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/*
    toxic - A Global Illumination Renderer
    Copyright (C) 2003-2004 Francois Beaune
    Contact: http://toxicengine.sourceforge.net/

    This file is part of toxic.

    toxic is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    (at your option) any later version.

    toxic 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 toxic; if not, write to the Free Software
    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
*/

#ifndef TOXIC_RENDERER_PHOTON_H
#define TOXIC_RENDERER_PHOTON_H

#include "common/math/point3.h"
#include "common/math/vector3.h"
#include "common/misc/binarystream.h"
#include "common/misc/types.h"
#include "color3.h"
#include "globals.h"
#include "utilities.h"

#include <cassert>

namespace toxic {

    //! The photon map implementation is based on the reference implementation
    //! provided by Henrik Wann Jensen in his book "Realistic Image Synthesis
    //! Using Photon Mapping".

    class Photon {
    public:
        sheep::float32 m_position[3];   //!< Position (12 bytes).

        Photon();

        void SetPosition(const sheep::Point3 &position);
        sheep::Point3 GetPosition() const;

        void SetPower(const Color3 &power);
        void ScalePower(sheep::Real scale);
        Color3 GetPower() const;

        //! Sets the photon incident direction. The direction vector must be
        //! unit-length, must go away from the surface carrying the photon
        //! and must be expressed in world space.
        void SetIncidentDirection(const sheep::Vector3 &direction);

        //! Returns the photon incident direction. The returned direction is
        //! a unit-length vector going away from the surface carrying the
        //! photon, and is expressed in world space.
        sheep::Vector3 GetIncidentDirection() const;

        void SetSplittingPlaneAxis(int axis);
        int GetSplittingPlaneAxis() const;

#ifdef ENABLE_RADIANCES_PRECOMPUTATION

        //! Returns true if this photon carries a precomputed radiance.
        bool HasPrecomputedRadiance() const;

        //! Radiance is expressed in W.m^-2.sr^-1.
        void SetPrecomputedRadiance(const Color3 &radiance);
        Color3 GetPrecomputedRadiance() const;

        //! Sets the surface normal at the photon position. The normal must be
        //! unit-length and must be expressed in world space.
        void SetSurfaceNormal(const sheep::Vector3 &normal);

        //! Returns the surface normal at the photon position. The returned normal
        //! is unit-length and is expressed in world space.
        sheep::Vector3 GetSurfaceNormal() const;

#endif  // ENABLE_RADIANCES_PRECOMPUTATION

        void WriteToStream(sheep::BinaryStream &os) const;
        void ReadFromStream(sheep::BinaryStream &is);

    private:
#ifdef COMPRESS_PHOTON_POWER
        sheep::uint8 m_power[4];        //!< Compressed power (4 bytes). Expressed in W.
#else
        sheep::float32 m_power[3];      //!< Full precision power (12 bytes). Expressed in W.
#endif  // COMPRESS_PHOTON_POWER

        sheep::uint8 m_qphi, m_qtheta;  //!< Compressed incident direction (2 bytes). Expressed in world space (away from the surface).

#ifdef ENABLE_RADIANCES_PRECOMPUTATION
#ifdef COMPRESS_PRECOMPUTED_RADIANCES
        sheep::uint8 m_radiance[4];     //!< Compressed precomputed radiance (4 bytes). Expressed in W.m^-2.sr^-1.
#else
        sheep::float32 m_radiance[3];   //!< Full precision precomputed radiance (12 bytes). Expressed in W.m^-2.sr^-1.
#endif  // COMPRESS_PRECOMPUTED_RADIANCES
        sheep::uint8 m_qnormal;         //!< Normal of the surface at the photon position (1 byte).
#endif  // ENABLE_RADIANCES_PRECOMPUTATION

        //! Various flags and data (2 bytes).
        //! Bits 1-0: splitting plane axis (for kd-tree construction).
        //! Bit 2: 1 if the photon carries an irradiance estimate, 0 otherwise.
        //! Do not change the size of this member unless you apply the change everywhere.
        sheep::uint16 m_flags;

        //!\todo Adjust padding according to the various #defines.
        sheep::uint8 m_padding[3];
    };

#include "photon.inl"

}

#endif  // !TOXIC_RENDERER_PHOTON_H

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