mitsuba/include/mitsuba/bidir/rsampler.h

99 lines
3.0 KiB
C++

/*
This file is part of Mitsuba, a physically based rendering system.
Copyright (c) 2007-2012 by Wenzel Jakob and others.
Mitsuba 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.
Mitsuba 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/>.
*/
#pragma once
#if !defined(__MITSUBA_BIDIR_RSAMPLER_H_)
#define __MITSUBA_BIDIR_RSAMPLER_H_
#include <mitsuba/render/sampler.h>
MTS_NAMESPACE_BEGIN
/**
* \brief Specialized sampler implementation used to seed MLT-style algorithm.
*
* Allows to query for the current sample index, which can later be used to rewind
* back to this state. In the case of MLT, this makes it possible to sample paths
* approximately proportional to their contribution without actually having
* to store millions of path. Note that `rewinding' is naive -- it just
* resets & regenerates the whole random number sequence, which might be slow.
*
* \ingroup libbidir
*/
class MTS_EXPORT_BIDIR ReplayableSampler : public Sampler {
public:
/// Construct a new sampler
ReplayableSampler();
/// Unserialize a sampler
ReplayableSampler(Stream *stream, InstanceManager *manager);
/**
* Create a clone of this sampler. The clone is allowed to be different
* to some extent, e.g. a pseudorandom generator should be based on a
* different random seed compared to the original. All other parameters,
* are copied exactly.
*/
virtual ref<Sampler> clone();
/* Does nothing in this implementation */
virtual void advance();
virtual void generate(const Point2i &pos);
/// Manually set the current sample index
virtual void setSampleIndex(size_t sampleIndex);
/// Retrieve the next component value from the current sample
virtual Float next1D();
/// Retrieve the next two component values from the current sample
virtual Point2 next2D();
/* Unsupported by this implementation */
virtual void request2DArray(size_t size);
virtual void request1DArray(size_t size);
/// Serialize this sampler to disk
virtual void serialize(Stream *stream, InstanceManager *manager) const;
/// Return a string description
virtual std::string toString() const;
/// Return the underlying random number generator
inline Random *getRandom() { return m_random; }
/**
* Update the current sample index, but without
* changing the RNG state. This is useful if the
* underlying random number generator has been used
* outside of this class
*/
inline void updateSampleIndex(size_t index) { m_sampleIndex = index; }
MTS_DECLARE_CLASS()
protected:
/// Virtual destructor
virtual ~ReplayableSampler();
protected:
ref<Random> m_initial, m_random;
};
MTS_NAMESPACE_END
#endif /* __MITSUBA_BIDIR_RSAMPLER_H_ */