assimp/code/TargetAnimation.cpp

/*
Open Asset Import Library (assimp)
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All rights reserved.

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  copyright notice, this list of conditions and the
  following disclaimer.

* Redistributions in binary form must reproduce the above
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  written permission of the assimp team.

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"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 
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*/

#include "TargetAnimation.h"
#include <algorithm>
#include "../include/assimp/ai_assert.h"

using namespace Assimp;


// ------------------------------------------------------------------------------------------------
KeyIterator::KeyIterator(const std::vector<aiVectorKey>* _objPos,
	const std::vector<aiVectorKey>* _targetObjPos,
	const aiVector3D*  defaultObjectPos /*= NULL*/,
	const aiVector3D*  defaultTargetPos /*= NULL*/)
		
		:	reachedEnd		(false)
		,	curTime			(-1.)
		,	objPos			(_objPos)
		,	targetObjPos	(_targetObjPos)
		,	nextObjPos		(0)
		,	nextTargetObjPos(0)
{
	// Generate default transformation tracks if necessary
	if (!objPos || objPos->empty())
	{
		defaultObjPos.resize(1);
		defaultObjPos.front().mTime  = 10e10;

		if (defaultObjectPos)
			defaultObjPos.front().mValue = *defaultObjectPos;

		objPos = & defaultObjPos;
	}
	if (!targetObjPos || targetObjPos->empty())
	{
		defaultTargetObjPos.resize(1);
		defaultTargetObjPos.front().mTime  = 10e10;

		if (defaultTargetPos)
			defaultTargetObjPos.front().mValue = *defaultTargetPos;

		targetObjPos = & defaultTargetObjPos;
	}
}

// ------------------------------------------------------------------------------------------------
template <class T>
inline T Interpolate(const T& one, const T& two, float val)
{
	return one + (two-one)*val;
}

// ------------------------------------------------------------------------------------------------
void KeyIterator::operator ++()
{
	// If we are already at the end of all keyframes, return
	if (reachedEnd) {
		return;
	}

	// Now search in all arrays for the time value closest
	// to our current position on the time line
	double d0,d1;
	
	d0 = objPos->at      ( std::min<unsigned int> ( nextObjPos, objPos->size()-1)             ).mTime;
	d1 = targetObjPos->at( std::min<unsigned int> ( nextTargetObjPos, targetObjPos->size()-1) ).mTime;	
	
	// Easiest case - all are identical. In this
	// case we don't need to interpolate so we can
	// return earlier
	if ( d0 == d1 )
	{
		curTime = d0;
		curPosition = objPos->at(nextObjPos).mValue;
		curTargetPosition = targetObjPos->at(nextTargetObjPos).mValue;

		// increment counters
		if (objPos->size() != nextObjPos-1)
			++nextObjPos;

		if (targetObjPos->size() != nextTargetObjPos-1)
			++nextTargetObjPos;
	}

	// An object position key is closest to us
	else if (d0 < d1)
	{
		curTime = d0;

		// interpolate the other
		if (1 == targetObjPos->size() || !nextTargetObjPos)	{
			curTargetPosition = targetObjPos->at(0).mValue;
		}
		else
		{
			const aiVectorKey& last  = targetObjPos->at(nextTargetObjPos);
			const aiVectorKey& first = targetObjPos->at(nextTargetObjPos-1);

			curTargetPosition = Interpolate(first.mValue, last.mValue, (float) (
				(curTime-first.mTime) / (last.mTime-first.mTime) ));
		}

		if (objPos->size() != nextObjPos-1)
			++nextObjPos;
	}
	// A target position key is closest to us
	else
	{
		curTime = d1;

		// interpolate the other
		if (1 == objPos->size() || !nextObjPos)	{
			curPosition = objPos->at(0).mValue;
		}
		else
		{
			const aiVectorKey& last  = objPos->at(nextObjPos);
			const aiVectorKey& first = objPos->at(nextObjPos-1);

			curPosition = Interpolate(first.mValue, last.mValue, (float) (
				(curTime-first.mTime) / (last.mTime-first.mTime)));
		}

		if (targetObjPos->size() != nextTargetObjPos-1)
			++nextTargetObjPos;
	}

	if (nextObjPos >= objPos->size()-1 &&
		nextTargetObjPos >= targetObjPos->size()-1)
	{
		// We reached the very last keyframe
		reachedEnd = true;
	}
}

// ------------------------------------------------------------------------------------------------
void TargetAnimationHelper::SetTargetAnimationChannel (
	const std::vector<aiVectorKey>* _targetPositions)
{
	ai_assert(NULL != _targetPositions);
	targetPositions = _targetPositions;
}

// ------------------------------------------------------------------------------------------------
void TargetAnimationHelper::SetMainAnimationChannel (
	const std::vector<aiVectorKey>* _objectPositions)
{
	ai_assert(NULL != _objectPositions);
	objectPositions = _objectPositions;
}

// ------------------------------------------------------------------------------------------------
void TargetAnimationHelper::SetFixedMainAnimationChannel(
	const aiVector3D& fixed)
{
	objectPositions = NULL; // just to avoid confusion
	fixedMain = fixed;
}

// ------------------------------------------------------------------------------------------------
void TargetAnimationHelper::Process(std::vector<aiVectorKey>* distanceTrack)
{
	ai_assert(NULL != targetPositions && NULL != distanceTrack);

	// TODO: in most cases we won't need the extra array
	std::vector<aiVectorKey>  real;
	
	std::vector<aiVectorKey>* fill = (distanceTrack == objectPositions ? &real : distanceTrack);
	fill->reserve(std::max( objectPositions->size(), targetPositions->size() ));

	// Iterate through all object keys and interpolate their values if necessary.
	// Then get the corresponding target position, compute the difference
	// vector between object and target position. Then compute a rotation matrix
	// that rotates the base vector of the object coordinate system at that time
	// to match the diff vector. 

	KeyIterator iter(objectPositions,targetPositions,&fixedMain);
	for (;!iter.Finished();++iter)
	{
		const aiVector3D&  position  = iter.GetCurPosition();
		const aiVector3D&  tposition = iter.GetCurTargetPosition();

		// diff vector
		aiVector3D diff = tposition - position;
		float f = diff.Length();

		// output distance vector
		if (f)
		{
			fill->push_back(aiVectorKey());
			aiVectorKey& v = fill->back();
			v.mTime  = iter.GetCurTime();
			v.mValue = diff;

			diff /= f;
		}
		else
		{
			// FIXME: handle this
		}

		// diff is now the vector in which our camera is pointing
	}

	if (real.size()) {
		*distanceTrack = real;
	}
}