assimp/code/ColladaExporter.cpp

/*
Open Asset Import Library (ASSIMP)
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Copyright (c) 2006-2010, ASSIMP Development Team
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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  following disclaimer in the documentation and/or other
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* Neither the name of the ASSIMP team, nor the names of its
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  derived from this software without specific prior
  written permission of the ASSIMP Development Team.

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"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 
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LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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*/

#include "AssimpPCH.h"

#ifndef ASSIMP_BUILD_NO_EXPORT
#include "ColladaExporter.h"

using namespace Assimp;

namespace Assimp
{

// ------------------------------------------------------------------------------------------------
// Worker function for exporting a scene to Collada. Prototyped and registered in Exporter.cpp
void ExportSceneCollada(const char* pFile,IOSystem* pIOSystem, const aiScene* pScene)
{
	// invoke the exporter 
	ColladaExporter iDoTheExportThing( pScene);

	// we're still here - export successfully completed. Write result to the given IOSYstem
	boost::scoped_ptr<IOStream> outfile (pIOSystem->Open(pFile,"wt"));

	// XXX maybe use a small wrapper around IOStream that behaves like std::stringstream in order to avoid the extra copy.
	outfile->Write( iDoTheExportThing.mOutput.str().c_str(),  iDoTheExportThing.mOutput.tellp(),1);
}

} // end of namespace Assimp


// ------------------------------------------------------------------------------------------------
// Constructor for a specific scene to export
ColladaExporter::ColladaExporter( const aiScene* pScene)
{
	mScene = pScene;

	// set up strings
	endstr = "\n"; // std::endl is too complicated for me to insert here.

	// start writing
	WriteFile();
}

// ------------------------------------------------------------------------------------------------
// Starts writing the contents
void ColladaExporter::WriteFile()
{
	// write the DTD
	mOutput << "<?xml version=\"1.0\"?>" << endstr;
	// COLLADA element start
	mOutput << "<COLLADA xmlns=\"http://www.collada.org/2005/11/COLLADASchema\" version=\"1.4.1\">" << endstr;
	PushTag();

	WriteHeader();

	WriteGeometryLibrary();

	WriteSceneLibrary();

	// useless Collada bullshit at the end, just in case we haven't had enough indirections, yet. 
	mOutput << startstr << "<scene>" << endstr;
	PushTag();
	mOutput << startstr << "<instance_visual_scene url=\"#myScene\" />" << endstr;
	PopTag();
	mOutput << startstr << "</scene>" << endstr;
	PopTag();
	mOutput << "</COLLADA>" << endstr;
}

// ------------------------------------------------------------------------------------------------
// Writes the asset header
void ColladaExporter::WriteHeader()
{
	// Dummy stuff. Nobody actually cares for it anyways
	mOutput << startstr << "<asset>" << endstr;
	PushTag();
	mOutput << startstr << "<contributor>" << endstr;
	PushTag();
	mOutput << startstr << "<author>Someone</author>" << endstr;
	mOutput << startstr << "<authoring_tool>Assimp Collada Exporter</authoring_tool>" << endstr;
	PopTag();
	mOutput << startstr << "</contributor>" << endstr;
	mOutput << startstr << "<unit meter=\"1.0\" name=\"meter\" />" << endstr;
	mOutput << startstr << "<up_axis>Y_UP</up_axis>" << endstr;
	PopTag();
	mOutput << startstr << "</asset>" << endstr;
}

// ------------------------------------------------------------------------------------------------
// Writes the geometry library
void ColladaExporter::WriteGeometryLibrary()
{
	mOutput << startstr << "<library_geometries>" << endstr;
	PushTag();

	for( size_t a = 0; a < mScene->mNumMeshes; ++a)
		WriteGeometry( a);

	PopTag();
	mOutput << startstr << "</library_geometries>" << endstr;
}

// ------------------------------------------------------------------------------------------------
// Writes the given mesh
void ColladaExporter::WriteGeometry( size_t pIndex)
{
	const aiMesh* mesh = mScene->mMeshes[pIndex];
	std::string idstr = GetMeshId( pIndex);

	// opening tag
	mOutput << startstr << "<geometry id=\"" << idstr << "\" name=\"" << idstr << "_name\" >" << endstr;
	PushTag();

	mOutput << startstr << "<mesh>" << endstr;
	PushTag();

	// Positions
	WriteFloatArray( idstr + "-positions", FloatType_Vector, (float*) mesh->mVertices, mesh->mNumVertices);
	// Normals, if any
	if( mesh->HasNormals() )
		WriteFloatArray( idstr + "-normals", FloatType_Vector, (float*) mesh->mNormals, mesh->mNumVertices);

	// texture coords
	for( size_t a = 0; a < AI_MAX_NUMBER_OF_TEXTURECOORDS; ++a)
	{
		if( mesh->HasTextureCoords( a) )
		{
			WriteFloatArray( idstr + "-tex" + boost::lexical_cast<std::string> (a), mesh->mNumUVComponents[a] == 3 ? FloatType_TexCoord3 : FloatType_TexCoord2,
				(float*) mesh->mTextureCoords[a], mesh->mNumVertices);
		}
	}

	// vertex colors
	for( size_t a = 0; a < AI_MAX_NUMBER_OF_TEXTURECOORDS; ++a)
	{
		if( mesh->HasVertexColors( a) )
			WriteFloatArray( idstr + "-color" + boost::lexical_cast<std::string> (a), FloatType_Color, (float*) mesh->mColors[a], mesh->mNumVertices);
	}

	// assemble vertex structure
	mOutput << startstr << "<vertices id=\"" << idstr << "-vertices" << "\">" << endstr;
	PushTag();
	mOutput << startstr << "<input semantic=\"POSITION\" source=\"#" << idstr << "-positions\" />" << endstr;
	if( mesh->HasNormals() )
		mOutput << startstr << "<input semantic=\"NORMAL\" source=\"#" << idstr << "-normals\" />" << endstr;
	for( size_t a = 0; a < AI_MAX_NUMBER_OF_TEXTURECOORDS; ++a )
	{
		if( mesh->HasTextureCoords( a) )
			mOutput << startstr << "<input semantic=\"TEXCOORD\" source=\"#" << idstr << "-tex" << a << "\" set=\"" << a << "\" />" << endstr;
	}
	for( size_t a = 0; a < AI_MAX_NUMBER_OF_COLOR_SETS; ++a )
	{
		if( mesh->HasVertexColors( a) )
			mOutput << startstr << "<input semantic=\"COLOR\" source=\"#" << idstr << "-color" << a << "\" set=\"" << a << "\" />" << endstr;
	}
	
	PopTag();
	mOutput << startstr << "</vertices>" << endstr;

	// write face setup
	mOutput << startstr << "<polylist count=\"" << mesh->mNumFaces << "\" material=\"tellme\">" << endstr;
	PushTag();
	mOutput << startstr << "<input offset=\"0\" semantic=\"VERTEX\" source=\"#" << idstr << "-vertices\" />" << endstr;
	
	mOutput << startstr << "<vcount>";
	for( size_t a = 0; a < mesh->mNumFaces; ++a )
		mOutput << mesh->mFaces[a].mNumIndices << " ";
	mOutput << "</vcount>" << endstr;
	
	mOutput << startstr << "<p>";
	for( size_t a = 0; a < mesh->mNumFaces; ++a )
	{
		const aiFace& face = mesh->mFaces[a];
		for( size_t b = 0; b < face.mNumIndices; ++b )
			mOutput << face.mIndices[b] << " ";
	}
	mOutput << "</p>" << endstr;
	PopTag();
	mOutput << startstr << "</polylist>" << endstr;

	// closing tags
	PopTag();
	mOutput << startstr << "</mesh>" << endstr;
	PopTag();
	mOutput << startstr << "</geometry>" << endstr;
}

// ------------------------------------------------------------------------------------------------
// Writes a float array of the given type
void ColladaExporter::WriteFloatArray( const std::string& pIdString, FloatDataType pType, const float* pData, size_t pElementCount)
{
	size_t floatsPerElement = 0;
	switch( pType )
	{
		case FloatType_Vector: floatsPerElement = 3; break;
		case FloatType_TexCoord2: floatsPerElement = 2; break;
		case FloatType_TexCoord3: floatsPerElement = 3; break;
		case FloatType_Color: floatsPerElement = 3; break;
		default:
			return;
	}

	std::string arrayId = pIdString + "-array";

	mOutput << startstr << "<source id=\"" << pIdString << "\" name=\"" << pIdString << "\">" << endstr;
	PushTag();

	// source array
	mOutput << startstr << "<float_array id=\"" << arrayId << "\" count=\"" << pElementCount * floatsPerElement << "\"> ";
	PushTag();

	if( pType == FloatType_TexCoord2 )
	{
		for( size_t a = 0; a < pElementCount; ++a )
		{
			mOutput << pData[a*3+0] << " ";
			mOutput << pData[a*3+1] << " ";
		}
	} 
	else if( pType == FloatType_Color )
	{
		for( size_t a = 0; a < pElementCount; ++a )
		{
			mOutput << pData[a*4+0] << " ";
			mOutput << pData[a*4+1] << " ";
			mOutput << pData[a*4+2] << " ";
		}
	}
	else
	{
		for( size_t a = 0; a < pElementCount * floatsPerElement; ++a )
			mOutput << pData[a] << " ";
	}
	mOutput << "</float_array>" << endstr; 
	PopTag();

	// the usual Collada bullshit. Let's bloat it even more!
	mOutput << startstr << "<technique_common>" << endstr;
	PushTag();
	mOutput << startstr << "<accessor count=\"" << pElementCount << "\" offset=\"0\" source=\"#" << arrayId << "\" stride=\"" << floatsPerElement << "\">" << endstr;
	PushTag();

	switch( pType )
	{
		case FloatType_Vector:
			mOutput << startstr << "<param name=\"X\" type=\"float\" />" << endstr;
			mOutput << startstr << "<param name=\"Y\" type=\"float\" />" << endstr;
			mOutput << startstr << "<param name=\"Z\" type=\"float\" />" << endstr;
			break;

		case FloatType_TexCoord2:
			mOutput << startstr << "<param name=\"S\" type=\"float\" />" << endstr;
			mOutput << startstr << "<param name=\"T\" type=\"float\" />" << endstr;
			break;

		case FloatType_TexCoord3:
			mOutput << startstr << "<param name=\"S\" type=\"float\" />" << endstr;
			mOutput << startstr << "<param name=\"T\" type=\"float\" />" << endstr;
			mOutput << startstr << "<param name=\"P\" type=\"float\" />" << endstr;
			break;

		case FloatType_Color:
			mOutput << startstr << "<param name=\"R\" type=\"float\" />" << endstr;
			mOutput << startstr << "<param name=\"G\" type=\"float\" />" << endstr;
			mOutput << startstr << "<param name=\"B\" type=\"float\" />" << endstr;
			break;
	}

	PopTag();
	mOutput << startstr << "</accessor>" << endstr;
	PopTag();
	mOutput << startstr << "</technique_common>" << endstr;
	PopTag();
	mOutput << startstr << "</source>" << endstr;
}

// ------------------------------------------------------------------------------------------------
// Writes the scene library
void ColladaExporter::WriteSceneLibrary()
{
	mOutput << startstr << "<library_visual_scenes>" << endstr;
	PushTag();
	mOutput << startstr << "<visual_scene id=\"myScene\" name=\"myScene\">" << endstr;
	PushTag();

	// start recursive write at the root node
	WriteNode( mScene->mRootNode);

	PopTag();
	mOutput << startstr << "</visual_scene>" << endstr;
	PopTag();
	mOutput << startstr << "</library_visual_scenes>" << endstr;
}

// ------------------------------------------------------------------------------------------------
// Recursively writes the given node
void ColladaExporter::WriteNode( const aiNode* pNode)
{
	mOutput << startstr << "<node id=\"" << pNode->mName.data << "\" name=\"" << pNode->mName.data << "\">" << endstr;
	PushTag();

	// write transformation - we can directly put the matrix there
	// TODO: (thom) decompose into scale - rot - quad to allow adressing it by animations afterwards
	const aiMatrix4x4& mat = pNode->mTransformation;
	mOutput << startstr << "<matrix>";
	mOutput << mat.a1 << " " << mat.a2 << " " << mat.a3 << " " << mat.a4 << " ";
	mOutput << mat.b1 << " " << mat.b2 << " " << mat.b3 << " " << mat.b4 << " ";
	mOutput << mat.c1 << " " << mat.c2 << " " << mat.c3 << " " << mat.c4 << " ";
	mOutput << mat.d1 << " " << mat.d2 << " " << mat.d3 << " " << mat.d4;
	mOutput << "</matrix>" << endstr;

	// instance every geometry
	for( size_t a = 0; a < pNode->mNumMeshes; ++a )
	{
		const aiMesh* mesh = mScene->mMeshes[pNode->mMeshes[a]];
		mOutput << startstr << "<instance_geometry url=\"#" << GetMeshId( a) << "\">" << endstr;
		PushTag();

		PopTag();
		mOutput << startstr << "</instance_geometry>" << endstr;
	}

	// recurse into subnodes
	for( size_t a = 0; a < pNode->mNumChildren; ++a )
		WriteNode( pNode->mChildren[a]);

	PopTag();
	mOutput << startstr << "</node>" << endstr;
}

#endif