assimp/code/BVHLoader.cpp

/** Implementation of the BVH loader */
/*
---------------------------------------------------------------------------
Open Asset Import Library (ASSIMP)
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Copyright (c) 2006-2008, ASSIMP Development Team

All rights reserved.

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THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 
"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 
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A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 
OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 
LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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*/

#include "AssimpPCH.h"
#include "../include/aiAnim.h"
#include "BVHLoader.h"
#include "fast_atof.h"
#include "SkeletonMeshBuilder.h"

using namespace Assimp;

// ------------------------------------------------------------------------------------------------
// Constructor to be privately used by Importer
BVHLoader::BVHLoader()
{}

// ------------------------------------------------------------------------------------------------
// Destructor, private as well
BVHLoader::~BVHLoader()
{}

// ------------------------------------------------------------------------------------------------
// Returns whether the class can handle the format of the given file. 
bool BVHLoader::CanRead( const std::string& pFile, IOSystem* pIOHandler) const
{
	// check file extension 
	std::string::size_type pos = pFile.find_last_of('.');
	// no file extension - can't read
	if( pos == std::string::npos)
		return false;
	std::string extension = pFile.substr( pos);
	for( std::string::iterator it = extension.begin(); it != extension.end(); ++it)
		*it = tolower( *it);

	return ( extension == ".bvh");
}

// ------------------------------------------------------------------------------------------------
// Imports the given file into the given scene structure. 
void BVHLoader::InternReadFile( const std::string& pFile, aiScene* pScene, IOSystem* pIOHandler)
{
	mFileName = pFile;

	// read file into memory
	boost::scoped_ptr<IOStream> file( pIOHandler->Open( pFile));
	if( file.get() == NULL)
		throw new ImportErrorException( "Failed to open file " + pFile + ".");

	size_t fileSize = file->FileSize();
	if( fileSize == 0)
		throw new ImportErrorException( "File is too small.");

	mBuffer.resize( fileSize);
	file->Read( &mBuffer.front(), 1, fileSize);

	// start reading
	mReader = mBuffer.begin();
	mLine = 1;
	ReadStructure( pScene);

	// build a dummy mesh for the skeleton so that we see something at least
	SkeletonMeshBuilder meshBuilder( pScene);

	// construct an animation from all the motion data we read
	CreateAnimation( pScene);
}

// ------------------------------------------------------------------------------------------------
// Reads the file
void BVHLoader::ReadStructure( aiScene* pScene)
{
	// first comes hierarchy
	std::string header = GetNextToken();
	if( header != "HIERARCHY")
		ThrowException( "Expected header string \"HIERARCHY\".");
	ReadHierarchy( pScene);

	// then comes the motion data
	std::string motion = GetNextToken();
	if( motion != "MOTION")
		ThrowException( "Expected beginning of motion data \"MOTION\".");
	ReadMotion( pScene);
}

// ------------------------------------------------------------------------------------------------
// Reads the hierarchy
void BVHLoader::ReadHierarchy( aiScene* pScene)
{
	std::string root = GetNextToken();
	if( root != "ROOT")
		ThrowException( "Expected root node \"ROOT\".");

	// Go read the hierarchy from here
	pScene->mRootNode = ReadNode();
}

// ------------------------------------------------------------------------------------------------
// Reads a node and recursively its childs and returns the created node;
aiNode* BVHLoader::ReadNode()
{
	// first token is name
	std::string nodeName = GetNextToken();
	if( nodeName.empty() || nodeName == "{")
		ThrowException( boost::str( boost::format( "Expected node name, but found \"%s\".") % nodeName));

	// then an opening brace should follow
	std::string openBrace = GetNextToken();
	if( openBrace != "{")
		ThrowException( boost::str( boost::format( "Expected opening brace \"{\", but found \"%s\".") % openBrace));

	// Create a node
	aiNode* node = new aiNode( nodeName);
	std::vector<aiNode*> childNodes;

	// and create an bone entry for it
	mNodes.push_back( Node( node));
	Node& internNode = mNodes.back();

	// now read the node's contents
	while( 1)
	{
		std::string token = GetNextToken();

		// node offset to parent node
		if( token == "OFFSET")
			ReadNodeOffset( node);
		else if( token == "CHANNELS")
			ReadNodeChannels( internNode);
		else if( token == "JOINT")
		{
			// child node follows
			aiNode* child = ReadNode();
			child->mParent = node;
			childNodes.push_back( child);
		} 
		else if( token == "End")
		{
			// The real symbol is "End Site". Second part comes in a separate token
			std::string siteToken = GetNextToken();
			if( siteToken != "Site")
				ThrowException( boost::str( boost::format( "Expected \"End Site\" keyword, but found \"%s %s\".") % token % siteToken));

			aiNode* child = ReadEndSite( nodeName);
			child->mParent = node;
			childNodes.push_back( child);
		} 
		else if( token == "}")
		{
			// we're done with that part of the hierarchy
			break;
		} else
		{
			// everything else is a parse error
			ThrowException( boost::str( boost::format( "Unknown keyword \"%s\".") % token));
		}
	}

	// add the child nodes if there are any
	if( childNodes.size() > 0)
	{
		node->mNumChildren = childNodes.size();
		node->mChildren = new aiNode*[node->mNumChildren];
		std::copy( childNodes.begin(), childNodes.end(), node->mChildren);
	}

	// and return the sub-hierarchy we built here
	return node;
}

// ------------------------------------------------------------------------------------------------
// Reads an end node and returns the created node.
aiNode* BVHLoader::ReadEndSite( const std::string& pParentName)
{
	// check opening brace
	std::string openBrace = GetNextToken();
	if( openBrace != "{")
		ThrowException( boost::str( boost::format( "Expected opening brace \"{\", but found \"%s\".") % openBrace));

	// Create a node
	aiNode* node = new aiNode( "EndSite_" + pParentName);

	// now read the node's contents. Only possible entry is "OFFSET"
	while( 1)
	{
		std::string token = GetNextToken();

		// end node's offset
		if( token == "OFFSET")
		{
			ReadNodeOffset( node);
		} 
		else if( token == "}")
		{
			// we're done with the end node
			break;
		} else
		{
			// everything else is a parse error
			ThrowException( boost::str( boost::format( "Unknown keyword \"%s\".") % token));
		}
	}

	// and return the sub-hierarchy we built here
	return node;
}
// ------------------------------------------------------------------------------------------------
// Reads a node offset for the given node
void BVHLoader::ReadNodeOffset( aiNode* pNode)
{
	// Offset consists of three floats to read
	aiVector3D offset;
	offset.x = GetNextTokenAsFloat();
	offset.y = GetNextTokenAsFloat();
	offset.z = GetNextTokenAsFloat();

	// build a transformation matrix from it
	pNode->mTransformation = aiMatrix4x4( 1.0f, 0.0f, 0.0f, offset.x, 0.0f, 1.0f, 0.0f, offset.y,
		0.0f, 0.0f, 1.0f, offset.z, 0.0f, 0.0f, 0.0f, 1.0f);
}

// ------------------------------------------------------------------------------------------------
// Reads the animation channels for the given node
void BVHLoader::ReadNodeChannels( BVHLoader::Node& pNode)
{
	// number of channels. Use the float reader because we're lazy
	float numChannelsFloat = GetNextTokenAsFloat();
	unsigned int numChannels = (unsigned int) numChannelsFloat;

	for( unsigned int a = 0; a < numChannels; a++)
	{
		std::string channelToken = GetNextToken();

		if( channelToken == "Xposition")
			pNode.mChannels.push_back( Channel_PositionX);
		else if( channelToken == "Yposition")
			pNode.mChannels.push_back( Channel_PositionY);
		else if( channelToken == "Zposition")
			pNode.mChannels.push_back( Channel_PositionZ);
		else if( channelToken == "Xrotation")
			pNode.mChannels.push_back( Channel_RotationX);
		else if( channelToken == "Yrotation")
			pNode.mChannels.push_back( Channel_RotationY);
		else if( channelToken == "Zrotation")
			pNode.mChannels.push_back( Channel_RotationZ);
		else
			ThrowException( boost::str( boost::format( "Invalid channel specifier \"%s\".") % channelToken));
	}
}

// ------------------------------------------------------------------------------------------------
// Reads the motion data
void BVHLoader::ReadMotion( aiScene* pScene)
{
	// Read number of frames
	std::string tokenFrames = GetNextToken();
	if( tokenFrames != "Frames:")
		ThrowException( boost::str( boost::format( "Expected frame count \"Frames:\", but found \"%s\".") % tokenFrames));

	float numFramesFloat = GetNextTokenAsFloat();
	mAnimNumFrames = (unsigned int) numFramesFloat;

	// Read frame duration
	std::string tokenDuration1 = GetNextToken();
	std::string tokenDuration2 = GetNextToken();
	if( tokenDuration1 != "Frame" || tokenDuration2 != "Time:")
		ThrowException( boost::str( boost::format( "Expected frame duration \"Frame Time:\", but found \"%s %s\".") % tokenDuration1 % tokenDuration2));

	mAnimTickDuration = GetNextTokenAsFloat();

	// resize value vectors for each node
	for( std::vector<Node>::iterator it = mNodes.begin(); it != mNodes.end(); ++it)
		it->mChannelValues.reserve( it->mChannels.size() * mAnimNumFrames);

	// now read all the data and store it in the corresponding node's value vector
	for( unsigned int frame = 0; frame < mAnimNumFrames; ++frame)
	{
		// on each line read the values for all nodes
		for( std::vector<Node>::iterator it = mNodes.begin(); it != mNodes.end(); ++it)
		{
			// get as many values as the node has channels
			for( unsigned int c = 0; c < it->mChannels.size(); ++c)
				it->mChannelValues.push_back( GetNextTokenAsFloat());
		}

		// after one frame worth of values for all nodes there should be a newline, but we better don't rely on it
	}
}

// ------------------------------------------------------------------------------------------------
// Retrieves the next token
std::string BVHLoader::GetNextToken()
{
	// skip any preceeding whitespace
	while( mReader != mBuffer.end())
	{
		if( !isspace( *mReader))
			break;

		// count lines
		if( *mReader == '\n')
			mLine++;

		++mReader;
	}

	// collect all chars till the next whitespace. BVH is easy in respect to that.
	std::string token;
	while( mReader != mBuffer.end())
	{
		if( isspace( *mReader))
			break;

		token.push_back( *mReader);
		++mReader;

		// little extra logic to make sure braces are counted correctly
		if( token == "{" || token == "}")
			break;
	}

	// empty token means end of file, which is just fine
	return token;
}

// ------------------------------------------------------------------------------------------------
// Reads the next token as a float
float BVHLoader::GetNextTokenAsFloat()
{
	std::string token = GetNextToken();
	if( token.empty())
		ThrowException( "Unexpected end of file while trying to read a float");

	// check if the float is valid by testing if the atof() function consumed every char of the token
	const char* ctoken = token.c_str();
	float result = 0.0f;
	ctoken = fast_atof_move( ctoken, result);

	if( ctoken != token.c_str() + token.length())
		ThrowException( boost::str( boost::format( "Expected a floating point number, but found \"%s\".") % token));

	return result;
}

// ------------------------------------------------------------------------------------------------
// Aborts the file reading with an exception
void BVHLoader::ThrowException( const std::string& pError)
{
	throw new ImportErrorException( boost::str( boost::format( "%s:%d - %s") % mFileName % mLine % pError));
}

// ------------------------------------------------------------------------------------------------
// Constructs an animation for the motion data and stores it in the given scene
void BVHLoader::CreateAnimation( aiScene* pScene)
{
	// create the animation
	pScene->mNumAnimations = 1;
	pScene->mAnimations = new aiAnimation*[1];
	aiAnimation* anim = new aiAnimation;
	pScene->mAnimations[0] = anim;

	// put down the basic parameters
	anim->mName.Set( "Motion");
	anim->mTicksPerSecond = 1.0 / double( mAnimTickDuration);
	anim->mDuration = double( mAnimNumFrames - 1);

	// now generate the tracks for all nodes
	anim->mNumChannels = mNodes.size();
	anim->mChannels = new aiNodeAnim*[anim->mNumChannels];

	// FIX: set the array elements to NULL to ensure proper deletion if an exception is thrown
	for (unsigned int i = 0; i < anim->mNumChannels;++i)
		anim->mChannels[i] = NULL;

	for( unsigned int a = 0; a < anim->mNumChannels; a++)
	{
		const Node& node = mNodes[a];
		const std::string nodeName = std::string( node.mNode->mName.data );
		aiNodeAnim* nodeAnim = new aiNodeAnim;
		anim->mChannels[a] = nodeAnim;
		nodeAnim->mNodeName.Set( nodeName);

		// translational part, if given
		if( node.mChannels.size() == 6)
		{
			nodeAnim->mNumPositionKeys = mAnimNumFrames;
			nodeAnim->mPositionKeys = new aiVectorKey[mAnimNumFrames];
			aiVectorKey* poskey = nodeAnim->mPositionKeys;
			for( unsigned int fr = 0; fr < mAnimNumFrames; ++fr)
			{
				poskey->mTime = double( fr);

				// Now compute all translations in the right order
				switch (node.mChannels[0])
				{	
				case Channel_PositionX: poskey->mValue.x = node.mChannelValues[fr * node.mChannels.size() + 0];break;
				case Channel_PositionY: poskey->mValue.y = node.mChannelValues[fr * node.mChannels.size() + 0];break;
				case Channel_PositionZ: poskey->mValue.z = node.mChannelValues[fr * node.mChannels.size() + 0];break;
				default: throw new ImportErrorException( "Unexpected animation channel setup at node " + nodeName );
				}

				switch (node.mChannels[1])
				{	
				case Channel_PositionX: poskey->mValue.x = node.mChannelValues[fr * node.mChannels.size() + 1];break;
				case Channel_PositionY: poskey->mValue.y = node.mChannelValues[fr * node.mChannels.size() + 1];break;
				case Channel_PositionZ: poskey->mValue.z = node.mChannelValues[fr * node.mChannels.size() + 1];break;
				default: throw new ImportErrorException( "Unexpected animation channel setup at node " + nodeName );
				}

				switch (node.mChannels[2])
				{	
				case Channel_PositionX: poskey->mValue.x = node.mChannelValues[fr * node.mChannels.size() + 2];break;
				case Channel_PositionY: poskey->mValue.y = node.mChannelValues[fr * node.mChannels.size() + 2];break;
				case Channel_PositionZ: poskey->mValue.z = node.mChannelValues[fr * node.mChannels.size() + 2];break;
				default: throw new ImportErrorException( "Unexpected animation channel setup at node " + nodeName );
				}

				poskey->mValue.z = node.mChannelValues[fr * node.mChannels.size() + 1];
				poskey->mValue.y = node.mChannelValues[fr * node.mChannels.size() + 2];
				++poskey;
			}
		} else
		{
			// if no translation part is given, put a default sequence
			aiVector3D nodePos( node.mNode->mTransformation.a4, node.mNode->mTransformation.b4, node.mNode->mTransformation.c4);
			nodeAnim->mNumPositionKeys = 1;
			nodeAnim->mPositionKeys = new aiVectorKey[1];
			nodeAnim->mPositionKeys[0].mTime = 0.0;
			nodeAnim->mPositionKeys[0].mValue = nodePos;
		}

		// rotation part. Always present. First find value offsets
		{
			unsigned int rotOffset  = 0;
			if( node.mChannels.size() == 6)
			{
				// Offset all further calculations
				rotOffset = 3;
			} 

			// Then create the number of rotation keys
			nodeAnim->mNumRotationKeys = mAnimNumFrames;
			nodeAnim->mRotationKeys = new aiQuatKey[mAnimNumFrames];
			aiQuatKey* rotkey = nodeAnim->mRotationKeys;
			for( unsigned int fr = 0; fr < mAnimNumFrames; ++fr)
			{
				// translate ZXY euler angels into a quaternion
				const float angle0 = node.mChannelValues[fr * node.mChannels.size() + rotOffset  ] * float( AI_MATH_PI) / 180.0f;
				const float angle1 = node.mChannelValues[fr * node.mChannels.size() + rotOffset+1] * float( AI_MATH_PI) / 180.0f;
				const float angle2 = node.mChannelValues[fr * node.mChannels.size() + rotOffset+2] * float( AI_MATH_PI) / 180.0f;

				aiMatrix4x4 temp;
				aiMatrix3x3 rotMatrix;
				
				// Compute rotation transformations in the right order
				switch (node.mChannels[rotOffset]) 
				{
				case Channel_RotationX: aiMatrix4x4::RotationX( angle0, temp); rotMatrix *= aiMatrix3x3( temp); break;
				case Channel_RotationY: aiMatrix4x4::RotationY( angle0, temp); rotMatrix *= aiMatrix3x3( temp);	break;
				case Channel_RotationZ: aiMatrix4x4::RotationZ( angle0, temp); rotMatrix *= aiMatrix3x3( temp); break;
				default: throw new ImportErrorException( "Unexpected animation channel setup at node " + nodeName );
				}
				switch (node.mChannels[rotOffset+1]) 
				{
				case Channel_RotationX: aiMatrix4x4::RotationX( angle1, temp); rotMatrix *= aiMatrix3x3( temp); break;
				case Channel_RotationY: aiMatrix4x4::RotationY( angle1, temp); rotMatrix *= aiMatrix3x3( temp);	break;
				case Channel_RotationZ: aiMatrix4x4::RotationZ( angle1, temp); rotMatrix *= aiMatrix3x3( temp); break;
				default: throw new ImportErrorException( "Unexpected animation channel setup at node " + nodeName );
				}
				switch (node.mChannels[rotOffset+2]) 
				{
				case Channel_RotationX: aiMatrix4x4::RotationX( angle2, temp); rotMatrix *= aiMatrix3x3( temp); break;
				case Channel_RotationY: aiMatrix4x4::RotationY( angle2, temp); rotMatrix *= aiMatrix3x3( temp);	break;
				case Channel_RotationZ: aiMatrix4x4::RotationZ( angle2, temp); rotMatrix *= aiMatrix3x3( temp); break;
				default: throw new ImportErrorException( "Unexpected animation channel setup at node " + nodeName );
				}

				rotkey->mTime = double( fr);
				rotkey->mValue = aiQuaternion( rotMatrix);
				++rotkey;
			}
		}

		// scaling part. Always just a default track
		{
			nodeAnim->mNumScalingKeys = 1;
			nodeAnim->mScalingKeys = new aiVectorKey[1];
			nodeAnim->mScalingKeys[0].mTime = 0.0;
			nodeAnim->mScalingKeys[0].mValue.Set( 1.0f, 1.0f, 1.0f);
		}
	}
}