/// \file   X3DImporter_Postprocess.cpp
/// \brief  Convert built scenegraph and objects to Assimp scenegraph.
/// \date   2015-2016
/// \author smal.root@gmail.com

#ifndef ASSIMP_BUILD_NO_X3D_IMPORTER

#include "X3DImporter.hpp"

// Header files, Assimp.
#include "StandardShapes.h"

// Header files, stdlib.
#include <algorithm>
#include <iterator>
#include <string>

namespace Assimp
{

aiMatrix4x4 X3DImporter::PostprocessHelper_Matrix_GlobalToCurrent() const
{
CX3DImporter_NodeElement* cur_node;
std::list<aiMatrix4x4> matr;
aiMatrix4x4 out_matr;

	// starting walk from current element to root
	cur_node = NodeElement_Cur;
	if(cur_node != nullptr)
	{
		do
		{
			// if cur_node is group then store group transformation matrix in list.
			if(cur_node->Type == CX3DImporter_NodeElement::ENET_Group) matr.push_back(((CX3DImporter_NodeElement_Group*)cur_node)->Transformation);

			cur_node = cur_node->Parent;
		} while(cur_node != nullptr);
	}

	// multiplicate all matrices in reverse order
	for(std::list<aiMatrix4x4>::reverse_iterator rit = matr.rbegin(); rit != matr.rend(); rit++) out_matr = out_matr * (*rit);

	return out_matr;
}

void X3DImporter::PostprocessHelper_CollectMetadata(const CX3DImporter_NodeElement& pNodeElement, std::list<CX3DImporter_NodeElement*>& pList) const
{
	// walk thru childs and find for metadata.
	for(std::list<CX3DImporter_NodeElement*>::const_iterator el_it = pNodeElement.Child.begin(); el_it != pNodeElement.Child.end(); el_it++)
	{
		if(((*el_it)->Type == CX3DImporter_NodeElement::ENET_MetaBoolean) || ((*el_it)->Type == CX3DImporter_NodeElement::ENET_MetaDouble) ||
			((*el_it)->Type == CX3DImporter_NodeElement::ENET_MetaFloat) || ((*el_it)->Type == CX3DImporter_NodeElement::ENET_MetaInteger) ||
			((*el_it)->Type == CX3DImporter_NodeElement::ENET_MetaString))
		{
			pList.push_back(*el_it);
		}
		else if((*el_it)->Type == CX3DImporter_NodeElement::ENET_MetaSet)
		{
			PostprocessHelper_CollectMetadata(**el_it, pList);
		}
	}// for(std::list<CX3DImporter_NodeElement*>::const_iterator el_it = pNodeElement.Child.begin(); el_it != pNodeElement.Child.end(); el_it++)
}

bool X3DImporter::PostprocessHelper_ElementIsMetadata(const CX3DImporter_NodeElement::EType pType) const
{
	if((pType == CX3DImporter_NodeElement::ENET_MetaBoolean) || (pType == CX3DImporter_NodeElement::ENET_MetaDouble) ||
		(pType == CX3DImporter_NodeElement::ENET_MetaFloat) || (pType == CX3DImporter_NodeElement::ENET_MetaInteger) ||
		(pType == CX3DImporter_NodeElement::ENET_MetaString) || (pType == CX3DImporter_NodeElement::ENET_MetaSet))
	{
		return true;
	}
	else
	{
		return false;
	}
}

bool X3DImporter::PostprocessHelper_ElementIsMesh(const CX3DImporter_NodeElement::EType pType) const
{
	if((pType == CX3DImporter_NodeElement::ENET_Arc2D) || (pType == CX3DImporter_NodeElement::ENET_ArcClose2D) ||
		(pType == CX3DImporter_NodeElement::ENET_Box) || (pType == CX3DImporter_NodeElement::ENET_Circle2D) ||
		(pType == CX3DImporter_NodeElement::ENET_Cone) || (pType == CX3DImporter_NodeElement::ENET_Cylinder) ||
		(pType == CX3DImporter_NodeElement::ENET_Disk2D) || (pType == CX3DImporter_NodeElement::ENET_ElevationGrid) ||
		(pType == CX3DImporter_NodeElement::ENET_Extrusion) || (pType == CX3DImporter_NodeElement::ENET_IndexedFaceSet) ||
		(pType == CX3DImporter_NodeElement::ENET_IndexedLineSet) || (pType == CX3DImporter_NodeElement::ENET_IndexedTriangleFanSet) ||
		(pType == CX3DImporter_NodeElement::ENET_IndexedTriangleSet) || (pType == CX3DImporter_NodeElement::ENET_IndexedTriangleStripSet) ||
		(pType == CX3DImporter_NodeElement::ENET_PointSet) || (pType == CX3DImporter_NodeElement::ENET_LineSet) ||
		(pType == CX3DImporter_NodeElement::ENET_Polyline2D) || (pType == CX3DImporter_NodeElement::ENET_Polypoint2D) ||
		(pType == CX3DImporter_NodeElement::ENET_Rectangle2D) || (pType == CX3DImporter_NodeElement::ENET_Sphere) ||
		(pType == CX3DImporter_NodeElement::ENET_TriangleFanSet) || (pType == CX3DImporter_NodeElement::ENET_TriangleSet) ||
		(pType == CX3DImporter_NodeElement::ENET_TriangleSet2D) || (pType == CX3DImporter_NodeElement::ENET_TriangleStripSet))
	{
		return true;
	}
	else
	{
		return false;
	}
}

void X3DImporter::Postprocess_BuildLight(const CX3DImporter_NodeElement& pNodeElement, std::list<aiLight*>& pSceneLightList) const
{
const CX3DImporter_NodeElement_Light& ne = *((CX3DImporter_NodeElement_Light*)&pNodeElement);
aiMatrix4x4 transform_matr = PostprocessHelper_Matrix_GlobalToCurrent();
aiLight* new_light = new aiLight;

	new_light->mName = ne.ID;
	new_light->mColorAmbient = ne.Color * ne.AmbientIntensity;
	new_light->mColorDiffuse = ne.Color * ne.Intensity;
	new_light->mColorSpecular = ne.Color * ne.Intensity;
	switch(pNodeElement.Type)
	{
		case CX3DImporter_NodeElement::ENET_DirectionalLight:
			new_light->mType = aiLightSource_DIRECTIONAL;
			new_light->mDirection = ne.Direction, new_light->mDirection *= transform_matr;

			break;
		case CX3DImporter_NodeElement::ENET_PointLight:
			new_light->mType = aiLightSource_POINT;
			new_light->mPosition = ne.Location, new_light->mPosition *= transform_matr;
			new_light->mAttenuationConstant = ne.Attenuation.x;
			new_light->mAttenuationLinear = ne.Attenuation.y;
			new_light->mAttenuationQuadratic = ne.Attenuation.z;

			break;
		case CX3DImporter_NodeElement::ENET_SpotLight:
			new_light->mType = aiLightSource_SPOT;
			new_light->mPosition = ne.Location, new_light->mPosition *= transform_matr;
			new_light->mDirection = ne.Direction, new_light->mDirection *= transform_matr;
			new_light->mAttenuationConstant = ne.Attenuation.x;
			new_light->mAttenuationLinear = ne.Attenuation.y;
			new_light->mAttenuationQuadratic = ne.Attenuation.z;
			new_light->mAngleInnerCone = ne.BeamWidth;
			new_light->mAngleOuterCone = ne.CutOffAngle;

			break;
		default:
			throw DeadlyImportError("Postprocess_BuildLight. Unknown type of light: " + std::to_string(pNodeElement.Type) + ".");
	}

	pSceneLightList.push_back(new_light);
}

void X3DImporter::Postprocess_BuildMaterial(const CX3DImporter_NodeElement& pNodeElement, aiMaterial** pMaterial) const
{
	// check argument
	if(pMaterial == nullptr) throw DeadlyImportError("Postprocess_BuildMaterial. pMaterial is nullptr.");
	if(*pMaterial != nullptr) throw DeadlyImportError("Postprocess_BuildMaterial. *pMaterial must be nullptr.");

	*pMaterial = new aiMaterial;
	aiMaterial& taimat = **pMaterial;// creating alias for convenience.

	// at this point pNodeElement point to <Appearance> node. Walk thru childs and add all stored data.
	for(std::list<CX3DImporter_NodeElement*>::const_iterator el_it = pNodeElement.Child.begin(); el_it != pNodeElement.Child.end(); el_it++)
	{
		if((*el_it)->Type == CX3DImporter_NodeElement::ENET_Material)
		{
			aiColor3D tcol3;
			float tvalf;
			CX3DImporter_NodeElement_Material& tnemat = *((CX3DImporter_NodeElement_Material*)*el_it);

			tcol3.r = tnemat.AmbientIntensity, tcol3.g = tnemat.AmbientIntensity, tcol3.b = tnemat.AmbientIntensity;
			taimat.AddProperty(&tcol3, 1, AI_MATKEY_COLOR_AMBIENT);
			taimat.AddProperty(&tnemat.DiffuseColor, 1, AI_MATKEY_COLOR_DIFFUSE);
			taimat.AddProperty(&tnemat.EmissiveColor, 1, AI_MATKEY_COLOR_EMISSIVE);
			taimat.AddProperty(&tnemat.SpecularColor, 1, AI_MATKEY_COLOR_SPECULAR);
			tvalf = 1;
			taimat.AddProperty(&tvalf, 1, AI_MATKEY_SHININESS_STRENGTH);
			taimat.AddProperty(&tnemat.Shininess, 1, AI_MATKEY_SHININESS);
			tvalf = 1.0f - tnemat.Transparency;
			taimat.AddProperty(&tvalf, 1, AI_MATKEY_OPACITY);
		}// if((*el_it)->Type == CX3DImporter_NodeElement::ENET_Material)
		else if((*el_it)->Type == CX3DImporter_NodeElement::ENET_ImageTexture)
		{
			CX3DImporter_NodeElement_ImageTexture& tnetex = *((CX3DImporter_NodeElement_ImageTexture*)*el_it);
			aiString url_str(tnetex.URL.c_str());
			int mode = aiTextureOp_Multiply;

			taimat.AddProperty(&url_str, AI_MATKEY_TEXTURE_DIFFUSE(0));
			taimat.AddProperty(&tnetex.RepeatS, 1, AI_MATKEY_MAPPINGMODE_U_DIFFUSE(0));
			taimat.AddProperty(&tnetex.RepeatT, 1, AI_MATKEY_MAPPINGMODE_V_DIFFUSE(0));
			taimat.AddProperty(&mode, 1, AI_MATKEY_TEXOP_DIFFUSE(0));
		}// else if((*el_it)->Type == CX3DImporter_NodeElement::ENET_ImageTexture)
		else if((*el_it)->Type == CX3DImporter_NodeElement::ENET_TextureTransform)
		{
			aiUVTransform trans;
			CX3DImporter_NodeElement_TextureTransform& tnetextr = *((CX3DImporter_NodeElement_TextureTransform*)*el_it);

			trans.mTranslation = tnetextr.Translation - tnetextr.Center;
			trans.mScaling = tnetextr.Scale;
			trans.mRotation = tnetextr.Rotation;
			taimat.AddProperty(&trans, 1, AI_MATKEY_UVTRANSFORM_DIFFUSE(0));
		}// else if((*el_it)->Type == CX3DImporter_NodeElement::ENET_TextureTransform)
	}// for(std::list<CX3DImporter_NodeElement*>::const_iterator el_it = pNodeElement.Child.begin(); el_it != pNodeElement.Child.end(); el_it++)
}

void X3DImporter::Postprocess_BuildMesh(const CX3DImporter_NodeElement& pNodeElement, aiMesh** pMesh) const
{
	// check argument
	if(pMesh == nullptr) throw DeadlyImportError("Postprocess_BuildMesh. pMesh is nullptr.");
	if(*pMesh != nullptr) throw DeadlyImportError("Postprocess_BuildMesh. *pMesh must be nullptr.");

	/************************************************************************************************************************************/
	/************************************************************ Geometry2D ************************************************************/
	/************************************************************************************************************************************/
	if((pNodeElement.Type == CX3DImporter_NodeElement::ENET_Arc2D) || (pNodeElement.Type == CX3DImporter_NodeElement::ENET_ArcClose2D) ||
		(pNodeElement.Type == CX3DImporter_NodeElement::ENET_Circle2D) || (pNodeElement.Type == CX3DImporter_NodeElement::ENET_Disk2D) ||
		(pNodeElement.Type == CX3DImporter_NodeElement::ENET_Polyline2D) || (pNodeElement.Type == CX3DImporter_NodeElement::ENET_Polypoint2D) ||
		(pNodeElement.Type == CX3DImporter_NodeElement::ENET_Rectangle2D) || (pNodeElement.Type == CX3DImporter_NodeElement::ENET_TriangleSet2D))
	{
		CX3DImporter_NodeElement_Geometry2D& tnemesh = *((CX3DImporter_NodeElement_Geometry2D*)&pNodeElement);// create alias for convenience
		std::vector<aiVector3D> tarr;

		tarr.reserve(tnemesh.Vertices.size());
		for(std::list<aiVector3D>::iterator it = tnemesh.Vertices.begin(); it != tnemesh.Vertices.end(); it++) tarr.push_back(*it);
		*pMesh = StandardShapes::MakeMesh(tarr, tnemesh.NumIndices);// create mesh from vertices using Assimp help.

		return;// mesh is build, nothing to do anymore.
	}
	/************************************************************************************************************************************/
	/************************************************************ Geometry3D ************************************************************/
	/************************************************************************************************************************************/
	//
	// Predefined figures
	//
	if((pNodeElement.Type == CX3DImporter_NodeElement::ENET_Box) || (pNodeElement.Type == CX3DImporter_NodeElement::ENET_Cone) ||
		(pNodeElement.Type == CX3DImporter_NodeElement::ENET_Cylinder) || (pNodeElement.Type == CX3DImporter_NodeElement::ENET_Sphere))
	{
		CX3DImporter_NodeElement_Geometry3D& tnemesh = *((CX3DImporter_NodeElement_Geometry3D*)&pNodeElement);// create alias for convenience
		std::vector<aiVector3D> tarr;

		tarr.reserve(tnemesh.Vertices.size());
		for(std::list<aiVector3D>::iterator it = tnemesh.Vertices.begin(); it != tnemesh.Vertices.end(); it++) tarr.push_back(*it);

		*pMesh = StandardShapes::MakeMesh(tarr, tnemesh.NumIndices);// create mesh from vertices using Assimp help.

		return;// mesh is build, nothing to do anymore.
	}
	//
	// Parametric figures
	//
	if(pNodeElement.Type == CX3DImporter_NodeElement::ENET_ElevationGrid)
	{
		CX3DImporter_NodeElement_ElevationGrid& tnemesh = *((CX3DImporter_NodeElement_ElevationGrid*)&pNodeElement);// create alias for convenience

		// at first create mesh from existing vertices.
		*pMesh = GeometryHelper_MakeMesh(tnemesh.CoordIdx, tnemesh.Vertices);
		// copy additional information from children
		for(std::list<CX3DImporter_NodeElement*>::iterator ch_it = tnemesh.Child.begin(); ch_it != tnemesh.Child.end(); ch_it++)
		{
			if((*ch_it)->Type == CX3DImporter_NodeElement::ENET_Color)
				MeshGeometry_AddColor(**pMesh, ((CX3DImporter_NodeElement_Color*)*ch_it)->Value, tnemesh.ColorPerVertex);
			else if((*ch_it)->Type == CX3DImporter_NodeElement::ENET_ColorRGBA)
				MeshGeometry_AddColor(**pMesh, ((CX3DImporter_NodeElement_ColorRGBA*)*ch_it)->Value, tnemesh.ColorPerVertex);
			else if((*ch_it)->Type == CX3DImporter_NodeElement::ENET_Normal)
				MeshGeometry_AddNormal(**pMesh,  ((CX3DImporter_NodeElement_Normal*)*ch_it)->Value, tnemesh.NormalPerVertex);
			else if((*ch_it)->Type == CX3DImporter_NodeElement::ENET_TextureCoordinate)
				MeshGeometry_AddTexCoord(**pMesh, ((CX3DImporter_NodeElement_TextureCoordinate*)*ch_it)->Value);
			else
				throw DeadlyImportError("Postprocess_BuildMesh. Unknown child of ElevationGrid: " + std::to_string((*ch_it)->Type) + ".");
		}// for(std::list<CX3DImporter_NodeElement*>::iterator ch_it = tnemesh.Child.begin(); ch_it != tnemesh.Child.end(); ch_it++)

		return;// mesh is build, nothing to do anymore.
	}// if(pNodeElement.Type == CX3DImporter_NodeElement::ENET_ElevationGrid)
	//
	// Indexed primitives sets
	//
	if(pNodeElement.Type == CX3DImporter_NodeElement::ENET_IndexedFaceSet)
	{
		CX3DImporter_NodeElement_IndexedSet& tnemesh = *((CX3DImporter_NodeElement_IndexedSet*)&pNodeElement);// create alias for convenience

		// at first search for <Coordinate> node and create mesh.
		for(std::list<CX3DImporter_NodeElement*>::iterator ch_it = tnemesh.Child.begin(); ch_it != tnemesh.Child.end(); ch_it++)
		{
			if((*ch_it)->Type == CX3DImporter_NodeElement::ENET_Coordinate)
			{
				*pMesh = GeometryHelper_MakeMesh(tnemesh.CoordIndex, ((CX3DImporter_NodeElement_Coordinate*)*ch_it)->Value);
			}
		}

		// copy additional information from children
		for(std::list<CX3DImporter_NodeElement*>::iterator ch_it = tnemesh.Child.begin(); ch_it != tnemesh.Child.end(); ch_it++)
		{
			if((*ch_it)->Type == CX3DImporter_NodeElement::ENET_Color)
				MeshGeometry_AddColor(**pMesh, tnemesh.CoordIndex, tnemesh.ColorIndex, ((CX3DImporter_NodeElement_Color*)*ch_it)->Value, tnemesh.ColorPerVertex);
			else if((*ch_it)->Type == CX3DImporter_NodeElement::ENET_ColorRGBA)
				MeshGeometry_AddColor(**pMesh, tnemesh.CoordIndex, tnemesh.ColorIndex, ((CX3DImporter_NodeElement_ColorRGBA*)*ch_it)->Value,
										tnemesh.ColorPerVertex);
			else if((*ch_it)->Type == CX3DImporter_NodeElement::ENET_Coordinate)
				{} // skip because already read when mesh created.
			else if((*ch_it)->Type == CX3DImporter_NodeElement::ENET_Normal)
				MeshGeometry_AddNormal(**pMesh, tnemesh.CoordIndex, tnemesh.NormalIndex, ((CX3DImporter_NodeElement_Normal*)*ch_it)->Value,
										tnemesh.NormalPerVertex);
			else if((*ch_it)->Type == CX3DImporter_NodeElement::ENET_TextureCoordinate)
				MeshGeometry_AddTexCoord(**pMesh, tnemesh.CoordIndex, tnemesh.TexCoordIndex, ((CX3DImporter_NodeElement_TextureCoordinate*)*ch_it)->Value);
			else
				throw DeadlyImportError("Postprocess_BuildMesh. Unknown child of IndexedFaceSet: " + std::to_string((*ch_it)->Type) + ".");
		}// for(std::list<CX3DImporter_NodeElement*>::iterator ch_it = tnemesh.Child.begin(); ch_it != tnemesh.Child.end(); ch_it++)

		return;// mesh is build, nothing to do anymore.
	}// if(pNodeElement.Type == CX3DImporter_NodeElement::ENET_IndexedFaceSet)

	if(pNodeElement.Type == CX3DImporter_NodeElement::ENET_IndexedLineSet)
	{
		CX3DImporter_NodeElement_IndexedSet& tnemesh = *((CX3DImporter_NodeElement_IndexedSet*)&pNodeElement);// create alias for convenience

		// at first search for <Coordinate> node and create mesh.
		for(std::list<CX3DImporter_NodeElement*>::iterator ch_it = tnemesh.Child.begin(); ch_it != tnemesh.Child.end(); ch_it++)
		{
			if((*ch_it)->Type == CX3DImporter_NodeElement::ENET_Coordinate)
			{
				*pMesh = GeometryHelper_MakeMesh(tnemesh.CoordIndex, ((CX3DImporter_NodeElement_Coordinate*)*ch_it)->Value);
			}
		}

		// copy additional information from children
		for(std::list<CX3DImporter_NodeElement*>::iterator ch_it = tnemesh.Child.begin(); ch_it != tnemesh.Child.end(); ch_it++)
		{
			if((*ch_it)->Type == CX3DImporter_NodeElement::ENET_Color)
				MeshGeometry_AddColor(**pMesh, tnemesh.CoordIndex, tnemesh.ColorIndex, ((CX3DImporter_NodeElement_Color*)*ch_it)->Value, tnemesh.ColorPerVertex);
			else if((*ch_it)->Type == CX3DImporter_NodeElement::ENET_ColorRGBA)
				MeshGeometry_AddColor(**pMesh, tnemesh.CoordIndex, tnemesh.ColorIndex, ((CX3DImporter_NodeElement_ColorRGBA*)*ch_it)->Value,
										tnemesh.ColorPerVertex);
			else if((*ch_it)->Type == CX3DImporter_NodeElement::ENET_Coordinate)
				{} // skip because already read when mesh created.
			else
				throw DeadlyImportError("Postprocess_BuildMesh. Unknown child of IndexedLineSet: " + std::to_string((*ch_it)->Type) + ".");
		}// for(std::list<CX3DImporter_NodeElement*>::iterator ch_it = tnemesh.Child.begin(); ch_it != tnemesh.Child.end(); ch_it++)

		return;// mesh is build, nothing to do anymore.
	}// if(pNodeElement.Type == CX3DImporter_NodeElement::ENET_IndexedLineSet)

	if((pNodeElement.Type == CX3DImporter_NodeElement::ENET_IndexedTriangleSet) ||
		(pNodeElement.Type == CX3DImporter_NodeElement::ENET_IndexedTriangleFanSet) ||
		(pNodeElement.Type == CX3DImporter_NodeElement::ENET_IndexedTriangleStripSet))
	{
		CX3DImporter_NodeElement_IndexedSet& tnemesh = *((CX3DImporter_NodeElement_IndexedSet*)&pNodeElement);// create alias for convenience

		// at first search for <Coordinate> node and create mesh.
		for(std::list<CX3DImporter_NodeElement*>::iterator ch_it = tnemesh.Child.begin(); ch_it != tnemesh.Child.end(); ch_it++)
		{
			if((*ch_it)->Type == CX3DImporter_NodeElement::ENET_Coordinate)
			{
				*pMesh = GeometryHelper_MakeMesh(tnemesh.CoordIndex, ((CX3DImporter_NodeElement_Coordinate*)*ch_it)->Value);
			}
		}

		// copy additional information from children
		for(std::list<CX3DImporter_NodeElement*>::iterator ch_it = tnemesh.Child.begin(); ch_it != tnemesh.Child.end(); ch_it++)
		{
			if((*ch_it)->Type == CX3DImporter_NodeElement::ENET_Color)
				MeshGeometry_AddColor(**pMesh, tnemesh.CoordIndex, tnemesh.ColorIndex, ((CX3DImporter_NodeElement_Color*)*ch_it)->Value, tnemesh.ColorPerVertex);
			else if((*ch_it)->Type == CX3DImporter_NodeElement::ENET_ColorRGBA)
				MeshGeometry_AddColor(**pMesh, tnemesh.CoordIndex, tnemesh.ColorIndex, ((CX3DImporter_NodeElement_ColorRGBA*)*ch_it)->Value,
										tnemesh.ColorPerVertex);
			else if((*ch_it)->Type == CX3DImporter_NodeElement::ENET_Coordinate)
				{} // skip because already read when mesh created.
			else if((*ch_it)->Type == CX3DImporter_NodeElement::ENET_Normal)
				MeshGeometry_AddNormal(**pMesh, tnemesh.CoordIndex, tnemesh.NormalIndex, ((CX3DImporter_NodeElement_Normal*)*ch_it)->Value,
										tnemesh.NormalPerVertex);
			else if((*ch_it)->Type == CX3DImporter_NodeElement::ENET_TextureCoordinate)
				MeshGeometry_AddTexCoord(**pMesh, tnemesh.CoordIndex, tnemesh.TexCoordIndex, ((CX3DImporter_NodeElement_TextureCoordinate*)*ch_it)->Value);
			else
				throw DeadlyImportError("Postprocess_BuildMesh. Unknown child of IndexedTriangleSet or IndexedTriangleFanSet, or \
																	IndexedTriangleStripSet: " + std::to_string((*ch_it)->Type) + ".");
		}// for(std::list<CX3DImporter_NodeElement*>::iterator ch_it = tnemesh.Child.begin(); ch_it != tnemesh.Child.end(); ch_it++)

		return;// mesh is build, nothing to do anymore.
	}// if((pNodeElement.Type == CX3DImporter_NodeElement::ENET_IndexedTriangleFanSet) || (pNodeElement.Type == CX3DImporter_NodeElement::ENET_IndexedTriangleStripSet))

	if(pNodeElement.Type == CX3DImporter_NodeElement::ENET_Extrusion)
	{
		CX3DImporter_NodeElement_IndexedSet& tnemesh = *((CX3DImporter_NodeElement_IndexedSet*)&pNodeElement);// create alias for convenience

		*pMesh = GeometryHelper_MakeMesh(tnemesh.CoordIndex, tnemesh.Vertices);

		return;// mesh is build, nothing to do anymore.
	}// if(pNodeElement.Type == CX3DImporter_NodeElement::ENET_Extrusion)

	//
	// Primitives sets
	//
	if(pNodeElement.Type == CX3DImporter_NodeElement::ENET_PointSet)
	{
		CX3DImporter_NodeElement_Set& tnemesh = *((CX3DImporter_NodeElement_Set*)&pNodeElement);// create alias for convenience

		// at first search for <Coordinate> node and create mesh.
		for(std::list<CX3DImporter_NodeElement*>::iterator ch_it = tnemesh.Child.begin(); ch_it != tnemesh.Child.end(); ch_it++)
		{
			if((*ch_it)->Type == CX3DImporter_NodeElement::ENET_Coordinate)
			{
				std::vector<aiVector3D> vec_copy;

				vec_copy.reserve(((CX3DImporter_NodeElement_Coordinate*)*ch_it)->Value.size());
				for(std::list<aiVector3D>::const_iterator it = ((CX3DImporter_NodeElement_Coordinate*)*ch_it)->Value.begin();
					it != ((CX3DImporter_NodeElement_Coordinate*)*ch_it)->Value.end(); it++)
				{
					vec_copy.push_back(*it);
				}

				*pMesh = StandardShapes::MakeMesh(vec_copy, 1);
			}
		}

		// copy additional information from children
		for(std::list<CX3DImporter_NodeElement*>::iterator ch_it = tnemesh.Child.begin(); ch_it != tnemesh.Child.end(); ch_it++)
		{
			if((*ch_it)->Type == CX3DImporter_NodeElement::ENET_Color)
				MeshGeometry_AddColor(**pMesh, ((CX3DImporter_NodeElement_Color*)*ch_it)->Value, true);
			else if((*ch_it)->Type == CX3DImporter_NodeElement::ENET_ColorRGBA)
				MeshGeometry_AddColor(**pMesh, ((CX3DImporter_NodeElement_ColorRGBA*)*ch_it)->Value, true);
			else if((*ch_it)->Type == CX3DImporter_NodeElement::ENET_Coordinate)
				{} // skip because already read when mesh created.
			else
				throw DeadlyImportError("Postprocess_BuildMesh. Unknown child of PointSet: " + std::to_string((*ch_it)->Type) + ".");
		}// for(std::list<CX3DImporter_NodeElement*>::iterator ch_it = tnemesh.Child.begin(); ch_it != tnemesh.Child.end(); ch_it++)

		return;// mesh is build, nothing to do anymore.
	}// if(pNodeElement.Type == CX3DImporter_NodeElement::ENET_PointSet)

	if(pNodeElement.Type == CX3DImporter_NodeElement::ENET_LineSet)
	{
		CX3DImporter_NodeElement_Set& tnemesh = *((CX3DImporter_NodeElement_Set*)&pNodeElement);// create alias for convenience

		// at first search for <Coordinate> node and create mesh.
		for(std::list<CX3DImporter_NodeElement*>::iterator ch_it = tnemesh.Child.begin(); ch_it != tnemesh.Child.end(); ch_it++)
		{
			if((*ch_it)->Type == CX3DImporter_NodeElement::ENET_Coordinate)
			{
				*pMesh = GeometryHelper_MakeMesh(tnemesh.CoordIndex, ((CX3DImporter_NodeElement_Coordinate*)*ch_it)->Value);
			}
		}

		// copy additional information from children
		for(std::list<CX3DImporter_NodeElement*>::iterator ch_it = tnemesh.Child.begin(); ch_it != tnemesh.Child.end(); ch_it++)
		{
			if((*ch_it)->Type == CX3DImporter_NodeElement::ENET_Color)
				MeshGeometry_AddColor(**pMesh, ((CX3DImporter_NodeElement_Color*)*ch_it)->Value, true);
			else if((*ch_it)->Type == CX3DImporter_NodeElement::ENET_ColorRGBA)
				MeshGeometry_AddColor(**pMesh, ((CX3DImporter_NodeElement_ColorRGBA*)*ch_it)->Value, true);
			else if((*ch_it)->Type == CX3DImporter_NodeElement::ENET_Coordinate)
				{} // skip because already read when mesh created.
			else
				throw DeadlyImportError("Postprocess_BuildMesh. Unknown child of LineSet: " + std::to_string((*ch_it)->Type) + ".");
		}// for(std::list<CX3DImporter_NodeElement*>::iterator ch_it = tnemesh.Child.begin(); ch_it != tnemesh.Child.end(); ch_it++)

		return;// mesh is build, nothing to do anymore.
	}// if(pNodeElement.Type == CX3DImporter_NodeElement::ENET_LineSet)

	if(pNodeElement.Type == CX3DImporter_NodeElement::ENET_TriangleFanSet)
	{
		CX3DImporter_NodeElement_Set& tnemesh = *((CX3DImporter_NodeElement_Set*)&pNodeElement);// create alias for convenience

		// at first search for <Coordinate> node and create mesh.
		for(std::list<CX3DImporter_NodeElement*>::iterator ch_it = tnemesh.Child.begin(); ch_it != tnemesh.Child.end(); ch_it++)
		{
			if((*ch_it)->Type == CX3DImporter_NodeElement::ENET_Coordinate)
			{
				*pMesh = GeometryHelper_MakeMesh(tnemesh.CoordIndex, ((CX3DImporter_NodeElement_Coordinate*)*ch_it)->Value);
			}
		}

		// copy additional information from children
		for(std::list<CX3DImporter_NodeElement*>::iterator ch_it = tnemesh.Child.begin(); ch_it != tnemesh.Child.end(); ch_it++)
		{
			if((*ch_it)->Type == CX3DImporter_NodeElement::ENET_Color)
				MeshGeometry_AddColor(**pMesh, ((CX3DImporter_NodeElement_Color*)*ch_it)->Value,tnemesh.ColorPerVertex);
			else if((*ch_it)->Type == CX3DImporter_NodeElement::ENET_ColorRGBA)
				MeshGeometry_AddColor(**pMesh, ((CX3DImporter_NodeElement_ColorRGBA*)*ch_it)->Value, tnemesh.ColorPerVertex);
			else if((*ch_it)->Type == CX3DImporter_NodeElement::ENET_Coordinate)
				{} // skip because already read when mesh created.
			else if((*ch_it)->Type == CX3DImporter_NodeElement::ENET_Normal)
				MeshGeometry_AddNormal(**pMesh, tnemesh.CoordIndex, tnemesh.NormalIndex, ((CX3DImporter_NodeElement_Normal*)*ch_it)->Value,
										tnemesh.NormalPerVertex);
			else if((*ch_it)->Type == CX3DImporter_NodeElement::ENET_TextureCoordinate)
				MeshGeometry_AddTexCoord(**pMesh, tnemesh.CoordIndex, tnemesh.TexCoordIndex, ((CX3DImporter_NodeElement_TextureCoordinate*)*ch_it)->Value);
			else
				throw DeadlyImportError("Postprocess_BuildMesh. Unknown child of TrianlgeFanSet: " + std::to_string((*ch_it)->Type) + ".");
		}// for(std::list<CX3DImporter_NodeElement*>::iterator ch_it = tnemesh.Child.begin(); ch_it != tnemesh.Child.end(); ch_it++)

		return;// mesh is build, nothing to do anymore.
	}// if(pNodeElement.Type == CX3DImporter_NodeElement::ENET_TriangleFanSet)

	if(pNodeElement.Type == CX3DImporter_NodeElement::ENET_TriangleSet)
	{
		CX3DImporter_NodeElement_Set& tnemesh = *((CX3DImporter_NodeElement_Set*)&pNodeElement);// create alias for convenience

		// at first search for <Coordinate> node and create mesh.
		for(std::list<CX3DImporter_NodeElement*>::iterator ch_it = tnemesh.Child.begin(); ch_it != tnemesh.Child.end(); ch_it++)
		{
			if((*ch_it)->Type == CX3DImporter_NodeElement::ENET_Coordinate)
			{
				std::vector<aiVector3D> vec_copy;

				vec_copy.reserve(((CX3DImporter_NodeElement_Coordinate*)*ch_it)->Value.size());
				for(std::list<aiVector3D>::const_iterator it = ((CX3DImporter_NodeElement_Coordinate*)*ch_it)->Value.begin();
					it != ((CX3DImporter_NodeElement_Coordinate*)*ch_it)->Value.end(); it++)
				{
					vec_copy.push_back(*it);
				}

				*pMesh = StandardShapes::MakeMesh(vec_copy, 3);
			}
		}

		// copy additional information from children
		for(std::list<CX3DImporter_NodeElement*>::iterator ch_it = tnemesh.Child.begin(); ch_it != tnemesh.Child.end(); ch_it++)
		{
			if((*ch_it)->Type == CX3DImporter_NodeElement::ENET_Color)
				MeshGeometry_AddColor(**pMesh, ((CX3DImporter_NodeElement_Color*)*ch_it)->Value, tnemesh.ColorPerVertex);
			else if((*ch_it)->Type == CX3DImporter_NodeElement::ENET_ColorRGBA)
				MeshGeometry_AddColor(**pMesh, ((CX3DImporter_NodeElement_ColorRGBA*)*ch_it)->Value, tnemesh.ColorPerVertex);
			else if((*ch_it)->Type == CX3DImporter_NodeElement::ENET_Coordinate)
				{} // skip because already read when mesh created.
			else if((*ch_it)->Type == CX3DImporter_NodeElement::ENET_Normal)
				MeshGeometry_AddNormal(**pMesh, tnemesh.CoordIndex, tnemesh.NormalIndex, ((CX3DImporter_NodeElement_Normal*)*ch_it)->Value,
										tnemesh.NormalPerVertex);
			else if((*ch_it)->Type == CX3DImporter_NodeElement::ENET_TextureCoordinate)
				MeshGeometry_AddTexCoord(**pMesh, tnemesh.CoordIndex, tnemesh.TexCoordIndex, ((CX3DImporter_NodeElement_TextureCoordinate*)*ch_it)->Value);
			else
				throw DeadlyImportError("Postprocess_BuildMesh. Unknown child of TrianlgeSet: " + std::to_string((*ch_it)->Type) + ".");
		}// for(std::list<CX3DImporter_NodeElement*>::iterator ch_it = tnemesh.Child.begin(); ch_it != tnemesh.Child.end(); ch_it++)

		return;// mesh is build, nothing to do anymore.
	}// if(pNodeElement.Type == CX3DImporter_NodeElement::ENET_TriangleSet)

	if(pNodeElement.Type == CX3DImporter_NodeElement::ENET_TriangleStripSet)
	{
		CX3DImporter_NodeElement_Set& tnemesh = *((CX3DImporter_NodeElement_Set*)&pNodeElement);// create alias for convenience

		// at first search for <Coordinate> node and create mesh.
		for(std::list<CX3DImporter_NodeElement*>::iterator ch_it = tnemesh.Child.begin(); ch_it != tnemesh.Child.end(); ch_it++)
		{
			if((*ch_it)->Type == CX3DImporter_NodeElement::ENET_Coordinate)
			{
				*pMesh = GeometryHelper_MakeMesh(tnemesh.CoordIndex, ((CX3DImporter_NodeElement_Coordinate*)*ch_it)->Value);
			}
		}

		// copy additional information from children
		for(std::list<CX3DImporter_NodeElement*>::iterator ch_it = tnemesh.Child.begin(); ch_it != tnemesh.Child.end(); ch_it++)
		{
			if((*ch_it)->Type == CX3DImporter_NodeElement::ENET_Color)
				MeshGeometry_AddColor(**pMesh, ((CX3DImporter_NodeElement_Color*)*ch_it)->Value, tnemesh.ColorPerVertex);
			else if((*ch_it)->Type == CX3DImporter_NodeElement::ENET_ColorRGBA)
				MeshGeometry_AddColor(**pMesh, ((CX3DImporter_NodeElement_ColorRGBA*)*ch_it)->Value, tnemesh.ColorPerVertex);
			else if((*ch_it)->Type == CX3DImporter_NodeElement::ENET_Coordinate)
				{} // skip because already read when mesh created.
			else if((*ch_it)->Type == CX3DImporter_NodeElement::ENET_Normal)
				MeshGeometry_AddNormal(**pMesh, tnemesh.CoordIndex, tnemesh.NormalIndex, ((CX3DImporter_NodeElement_Normal*)*ch_it)->Value,
										tnemesh.NormalPerVertex);
			else if((*ch_it)->Type == CX3DImporter_NodeElement::ENET_TextureCoordinate)
				MeshGeometry_AddTexCoord(**pMesh, tnemesh.CoordIndex, tnemesh.TexCoordIndex, ((CX3DImporter_NodeElement_TextureCoordinate*)*ch_it)->Value);
			else
				throw DeadlyImportError("Postprocess_BuildMesh. Unknown child of TriangleStripSet: " + std::to_string((*ch_it)->Type) + ".");
		}// for(std::list<CX3DImporter_NodeElement*>::iterator ch_it = tnemesh.Child.begin(); ch_it != tnemesh.Child.end(); ch_it++)

		return;// mesh is build, nothing to do anymore.
	}// if(pNodeElement.Type == CX3DImporter_NodeElement::ENET_TriangleStripSet)

	throw DeadlyImportError("Postprocess_BuildMesh. Unknown mesh type: " + std::to_string(pNodeElement.Type) + ".");
}

void X3DImporter::Postprocess_BuildNode(const CX3DImporter_NodeElement& pNodeElement, aiNode& pSceneNode, std::list<aiMesh*>& pSceneMeshList,
										std::list<aiMaterial*>& pSceneMaterialList, std::list<aiLight*>& pSceneLightList) const
{
std::list<CX3DImporter_NodeElement*>::const_iterator chit_begin = pNodeElement.Child.begin();
std::list<CX3DImporter_NodeElement*>::const_iterator chit_end = pNodeElement.Child.end();
std::list<aiNode*> SceneNode_Child;
std::list<unsigned int> SceneNode_Mesh;

	// At first read all metadata
	Postprocess_CollectMetadata(pNodeElement, pSceneNode);
	// check if we have deal with grouping node. Which can contain transformation or switch
	if(pNodeElement.Type == CX3DImporter_NodeElement::ENET_Group)
	{
		const CX3DImporter_NodeElement_Group& tne_group = *((CX3DImporter_NodeElement_Group*)&pNodeElement);// create alias for convenience

		pSceneNode.mTransformation = tne_group.Transformation;
		if(tne_group.UseChoice)
		{
			// If Choice is less than zero or greater than the number of nodes in the children field, nothing is chosen.
			if((tne_group.Choice < 0) || ((size_t)tne_group.Choice >= pNodeElement.Child.size()))
			{
				chit_begin = pNodeElement.Child.end();
				chit_end = pNodeElement.Child.end();
			}
			else
			{
				for(size_t i = 0; i < (size_t)tne_group.Choice; i++) chit_begin++;// forward iterator to choosed node.

				chit_end = chit_begin;
				chit_end++;// point end iterator to next element after choosed.
			}
		}// if(tne_group.UseChoice)
	}// if(pNodeElement.Type == CX3DImporter_NodeElement::ENET_Group)

	// Reserve memory for fast access and check children.
	for(std::list<CX3DImporter_NodeElement*>::const_iterator it = chit_begin; it != chit_end; it++)
	{// in this loop we do not read metadata because it's already read at begin.
		if((*it)->Type == CX3DImporter_NodeElement::ENET_Group)
		{
			// if child is group then create new node and do recursive call.
			aiNode* new_node = new aiNode;

			new_node->mName = (*it)->ID;
			new_node->mParent = &pSceneNode;
			SceneNode_Child.push_back(new_node);
			Postprocess_BuildNode(**it, *new_node, pSceneMeshList, pSceneMaterialList, pSceneLightList);
		}
		else if((*it)->Type == CX3DImporter_NodeElement::ENET_Shape)
		{
			// shape can contain only one geometry and one appearance nodes.
			Postprocess_BuildShape(*((CX3DImporter_NodeElement_Shape*)*it), SceneNode_Mesh, pSceneMeshList, pSceneMaterialList);
		}
		else if(((*it)->Type == CX3DImporter_NodeElement::ENET_DirectionalLight) || ((*it)->Type == CX3DImporter_NodeElement::ENET_PointLight) ||
				((*it)->Type == CX3DImporter_NodeElement::ENET_SpotLight))
		{
			Postprocess_BuildLight(*((CX3DImporter_NodeElement_Light*)*it), pSceneLightList);
		}
		else if(!PostprocessHelper_ElementIsMetadata((*it)->Type))// skip metadata
		{
			throw DeadlyImportError("Postprocess_BuildNode. Unknown type: " + std::to_string((*it)->Type) + ".");
		}
	}// for(std::list<CX3DImporter_NodeElement*>::const_iterator it = chit_begin; it != chit_end; it++)

	// copy data about children and meshes to aiNode.
	if(SceneNode_Child.size() > 0)
	{
		std::list<aiNode*>::const_iterator it = SceneNode_Child.begin();

		pSceneNode.mNumChildren = SceneNode_Child.size();
		pSceneNode.mChildren = new aiNode*[pSceneNode.mNumChildren];
		for(size_t i = 0; i < pSceneNode.mNumChildren; i++) pSceneNode.mChildren[i] = *it++;
	}

	if(SceneNode_Mesh.size() > 0)
	{
		std::list<unsigned int>::const_iterator it = SceneNode_Mesh.begin();

		pSceneNode.mNumMeshes = SceneNode_Mesh.size();
		pSceneNode.mMeshes = new unsigned int[pSceneNode.mNumMeshes];
		for(size_t i = 0; i < pSceneNode.mNumMeshes; i++) pSceneNode.mMeshes[i] = *it++;
	}

	// that's all. return to previous deals
}

void X3DImporter::Postprocess_BuildShape(const CX3DImporter_NodeElement_Shape& pShapeNodeElement, std::list<unsigned int>& pNodeMeshInd,
							std::list<aiMesh*>& pSceneMeshList, std::list<aiMaterial*>& pSceneMaterialList) const
{
aiMaterial* tmat = nullptr;
aiMesh* tmesh = nullptr;
CX3DImporter_NodeElement::EType mesh_type = CX3DImporter_NodeElement::ENET_Invalid;
unsigned int mat_ind = 0;

	for(std::list<CX3DImporter_NodeElement*>::const_iterator it = pShapeNodeElement.Child.begin(); it != pShapeNodeElement.Child.end(); it++)
	{
		if(PostprocessHelper_ElementIsMesh((*it)->Type))
		{
			Postprocess_BuildMesh(**it, &tmesh);
			if(tmesh != nullptr)
			{
				// if mesh successfully built then add data about it to arrays
				pNodeMeshInd.push_back(pSceneMeshList.size());
				pSceneMeshList.push_back(tmesh);
				// keep mesh type. Need above for texture coordinate generation.
				mesh_type = (*it)->Type;
			}
		}
		else if((*it)->Type == CX3DImporter_NodeElement::ENET_Appearance)
		{
			Postprocess_BuildMaterial(**it, &tmat);
			if(tmat != nullptr)
			{
				// if material successfully built then add data about it to array
				mat_ind = pSceneMaterialList.size();
				pSceneMaterialList.push_back(tmat);
			}
		}
	}// for(std::list<CX3DImporter_NodeElement*>::const_iterator it = pShapeNodeElement.Child.begin(); it != pShapeNodeElement.Child.end(); it++)

	// associate read material with read mesh.
	if((tmesh != nullptr) && (tmat != nullptr))
	{
		tmesh->mMaterialIndex = mat_ind;
		// Check texture mapping. If material has texture but mesh has no texture coordinate then try to ask Assimp to generate texture coordinates.
		if((tmat->GetTextureCount(aiTextureType_DIFFUSE) != 0) && !tmesh->HasTextureCoords(0))
		{
			int32_t tm;
			aiVector3D tvec3;

			switch(mesh_type)
			{
				case CX3DImporter_NodeElement::ENET_Box:
					tm = aiTextureMapping_BOX;
					break;
				case CX3DImporter_NodeElement::ENET_Cone:
				case CX3DImporter_NodeElement::ENET_Cylinder:
					tm = aiTextureMapping_CYLINDER;
					break;
				case CX3DImporter_NodeElement::ENET_Sphere:
					tm = aiTextureMapping_SPHERE;
					break;
				default:
					tm = aiTextureMapping_PLANE;
					break;
			}// switch(mesh_type)

			tmat->AddProperty(&tm, 1, AI_MATKEY_MAPPING_DIFFUSE(0));
		}// if((tmat->GetTextureCount(aiTextureType_DIFFUSE) != 0) && !tmesh->HasTextureCoords(0))
	}// if((tmesh != nullptr) && (tmat != nullptr))
}

void X3DImporter::Postprocess_CollectMetadata(const CX3DImporter_NodeElement& pNodeElement, aiNode& pSceneNode) const
{
std::list<CX3DImporter_NodeElement*> meta_list;
size_t meta_idx;

	PostprocessHelper_CollectMetadata(pNodeElement, meta_list);// find metadata in current node element.
	if(meta_list.size() > 0)
	{
		if(pSceneNode.mMetaData != nullptr) throw DeadlyImportError("Postprocess. MetaData member in node are not nullptr. Something went wrong.");

		// copy collected metadata to output node.
		pSceneNode.mMetaData = new aiMetadata();
		pSceneNode.mMetaData->mNumProperties = meta_list.size();
		pSceneNode.mMetaData->mKeys = new aiString[pSceneNode.mMetaData->mNumProperties];
		pSceneNode.mMetaData->mValues = new aiMetadataEntry[pSceneNode.mMetaData->mNumProperties];
		meta_idx = 0;
		for(std::list<CX3DImporter_NodeElement*>::const_iterator it = meta_list.begin(); it != meta_list.end(); it++, meta_idx++)
		{
			CX3DImporter_NodeElement_Meta* cur_meta = (CX3DImporter_NodeElement_Meta*)*it;

			// due to limitations we can add only first element of value list.
			// Add an element according to its type.
			if((*it)->Type == CX3DImporter_NodeElement::ENET_MetaBoolean)
			{
				if(((CX3DImporter_NodeElement_MetaBoolean*)cur_meta)->Value.size() > 0)
					pSceneNode.mMetaData->Set(meta_idx, cur_meta->Name, *(((CX3DImporter_NodeElement_MetaBoolean*)cur_meta)->Value.begin()));
			}
			else if((*it)->Type == CX3DImporter_NodeElement::ENET_MetaDouble)
			{
				// at this case also converting double to float.
				if(((CX3DImporter_NodeElement_MetaBoolean*)cur_meta)->Value.size() > 0)
					pSceneNode.mMetaData->Set(meta_idx, cur_meta->Name, (float)*(((CX3DImporter_NodeElement_MetaDouble*)cur_meta)->Value.begin()));
			}
			else if((*it)->Type == CX3DImporter_NodeElement::ENET_MetaFloat)
			{
				if(((CX3DImporter_NodeElement_MetaBoolean*)cur_meta)->Value.size() > 0)
					pSceneNode.mMetaData->Set(meta_idx, cur_meta->Name, *(((CX3DImporter_NodeElement_MetaFloat*)cur_meta)->Value.begin()));
			}
			else if((*it)->Type == CX3DImporter_NodeElement::ENET_MetaInteger)
			{
				if(((CX3DImporter_NodeElement_MetaBoolean*)cur_meta)->Value.size() > 0)
					pSceneNode.mMetaData->Set(meta_idx, cur_meta->Name, *(((CX3DImporter_NodeElement_MetaInteger*)cur_meta)->Value.begin()));
			}
			else if((*it)->Type == CX3DImporter_NodeElement::ENET_MetaString)
			{
				if(((CX3DImporter_NodeElement_MetaBoolean*)cur_meta)->Value.size() > 0)
					pSceneNode.mMetaData->Set(meta_idx, cur_meta->Name, ((CX3DImporter_NodeElement_MetaString*)cur_meta)->Value.begin()->data());
			}
			else
			{
				throw DeadlyImportError("Postprocess. Unknown metadata type.");
			}// if((*it)->Type == CX3DImporter_NodeElement::ENET_Meta*) else
		}// for(std::list<CX3DImporter_NodeElement*>::const_iterator it = meta_list.begin(); it != meta_list.end(); it++)
	}// if(meta_list.size() > 0)
}

}// namespace Assimp

#endif // !ASSIMP_BUILD_NO_X3D_IMPORTER