/*
---------------------------------------------------------------------------
Open Asset Import Library (assimp)
---------------------------------------------------------------------------

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  following disclaimer.

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*/

/** @file  3DSLoader.cpp
 *  @brief Implementation of the 3ds importer class
 *
 *  http://www.the-labs.com/Blender/3DS-details.html
 */

#include "AssimpPCH.h"
#ifndef ASSIMP_BUILD_NO_3DS_IMPORTER

// internal headers
#include "3DSLoader.h"

using namespace Assimp;

static const aiImporterDesc desc = {
	"Discreet 3DS Importer",
	"",
	"",
	"Limited animation support",
	aiImporterFlags_SupportBinaryFlavour,
	0,
	0,
	0,
	0,
	"3ds prj" 
};

		
// ------------------------------------------------------------------------------------------------
// Begins a new parsing block
// - Reads the current chunk and validates it
// - computes its length
#define ASSIMP_3DS_BEGIN_CHUNK()                                         \
	while (true) {                                                       \
	if (stream->GetRemainingSizeToLimit() < sizeof(Discreet3DS::Chunk)){ \
		return;                                                          \
	}                                                                    \
	Discreet3DS::Chunk chunk;                                            \
	ReadChunk(&chunk);                                                   \
	int chunkSize = chunk.Size-sizeof(Discreet3DS::Chunk);	             \
    if(chunkSize <= 0)                                                   \
        continue;                                                        \
	const int oldReadLimit = stream->GetReadLimit();                     \
	stream->SetReadLimit(stream->GetCurrentPos() + chunkSize);           \
	

// ------------------------------------------------------------------------------------------------
// End a parsing block
// Must follow at the end of each parsing block, reset chunk end marker to previous value
#define ASSIMP_3DS_END_CHUNK()                  \
	stream->SkipToReadLimit();                  \
	stream->SetReadLimit(oldReadLimit);         \
	if (stream->GetRemainingSizeToLimit() == 0) \
		return;                                 \
	}

// ------------------------------------------------------------------------------------------------
// Constructor to be privately used by Importer
Discreet3DSImporter::Discreet3DSImporter()
{}

// ------------------------------------------------------------------------------------------------
// Destructor, private as well 
Discreet3DSImporter::~Discreet3DSImporter()
{}

// ------------------------------------------------------------------------------------------------
// Returns whether the class can handle the format of the given file. 
bool Discreet3DSImporter::CanRead( const std::string& pFile, IOSystem* pIOHandler, bool checkSig) const
{
	std::string extension = GetExtension(pFile);
	if(extension == "3ds" || extension == "prj" ) {
		return true;
	}
	if (!extension.length() || checkSig) {
		uint16_t token[3];
		token[0] = 0x4d4d;
		token[1] = 0x3dc2;
		//token[2] = 0x3daa;
		return CheckMagicToken(pIOHandler,pFile,token,2,0,2);
	}
	return false;
}

// ------------------------------------------------------------------------------------------------
// Loader registry entry
const aiImporterDesc* Discreet3DSImporter::GetInfo () const
{
	return &desc;
}

// ------------------------------------------------------------------------------------------------
// Setup configuration properties
void Discreet3DSImporter::SetupProperties(const Importer* /*pImp*/)
{
	// nothing to be done for the moment
}

// ------------------------------------------------------------------------------------------------
// Imports the given file into the given scene structure. 
void Discreet3DSImporter::InternReadFile( const std::string& pFile, 
	aiScene* pScene, IOSystem* pIOHandler)
{
	StreamReaderLE stream(pIOHandler->Open(pFile,"rb"));
	this->stream = &stream;

	// We should have at least one chunk
	if (stream.GetRemainingSize() < 16) {
		throw DeadlyImportError("3DS file is either empty or corrupt: " + pFile);
	}

	// Allocate our temporary 3DS representation
	mScene = new D3DS::Scene();

	// Initialize members
	mLastNodeIndex             = -1;
	mCurrentNode               = new D3DS::Node();
	mRootNode                  = mCurrentNode;
	mRootNode->mHierarchyPos   = -1;
	mRootNode->mHierarchyIndex = -1;
	mRootNode->mParent         = NULL;
	mMasterScale               = 1.0f;
	mBackgroundImage           = "";
	bHasBG                     = false;
	bIsPrj                     = false;

	// Parse the file
	ParseMainChunk();

	// Process all meshes in the file. First check whether all
	// face indices haev valid values. The generate our 
	// internal verbose representation. Finally compute normal
	// vectors from the smoothing groups we read from the
	// file.
	for (std::vector<D3DS::Mesh>::iterator i = mScene->mMeshes.begin(),
		 end = mScene->mMeshes.end(); i != end;++i)	{
		CheckIndices(*i);
		MakeUnique  (*i);
		ComputeNormalsWithSmoothingsGroups<D3DS::Face>(*i);
	}

	// Replace all occurences of the default material with a
	// valid material. Generate it if no material containing
	// DEFAULT in its name has been found in the file
	ReplaceDefaultMaterial();

	// Convert the scene from our internal representation to an
	// aiScene object. This involves copying all meshes, lights
	// and cameras to the scene
	ConvertScene(pScene);

	// Generate the node graph for the scene. This is a little bit
	// tricky since we'll need to split some meshes into submeshes
	GenerateNodeGraph(pScene);

	// Now apply the master scaling factor to the scene
	ApplyMasterScale(pScene);

	// Delete our internal scene representation and the root
	// node, so the whole hierarchy will follow
	delete mRootNode;
	delete mScene;

	AI_DEBUG_INVALIDATE_PTR(mRootNode);
	AI_DEBUG_INVALIDATE_PTR(mScene);
	AI_DEBUG_INVALIDATE_PTR(this->stream);
}

// ------------------------------------------------------------------------------------------------
// Applies a master-scaling factor to the imported scene
void Discreet3DSImporter::ApplyMasterScale(aiScene* pScene)
{
	// There are some 3DS files with a zero scaling factor
	if (!mMasterScale)mMasterScale = 1.0f;
	else mMasterScale = 1.0f / mMasterScale;

	// Construct an uniform scaling matrix and multiply with it
	pScene->mRootNode->mTransformation *= aiMatrix4x4( 
		mMasterScale,0.0f, 0.0f, 0.0f,
		0.0f, mMasterScale,0.0f, 0.0f,
		0.0f, 0.0f, mMasterScale,0.0f,
		0.0f, 0.0f, 0.0f, 1.0f);

	// Check whether a scaling track is assigned to the root node.
}

// ------------------------------------------------------------------------------------------------
// Reads a new chunk from the file
void Discreet3DSImporter::ReadChunk(Discreet3DS::Chunk* pcOut)
{
	ai_assert(pcOut != NULL);

	pcOut->Flag = stream->GetI2();
	pcOut->Size = stream->GetI4();

	if (pcOut->Size - sizeof(Discreet3DS::Chunk) > stream->GetRemainingSize())
		throw DeadlyImportError("Chunk is too large");
	
	if (pcOut->Size - sizeof(Discreet3DS::Chunk) > stream->GetRemainingSizeToLimit())
		DefaultLogger::get()->error("3DS: Chunk overflow");
}

// ------------------------------------------------------------------------------------------------
// Skip a chunk
void Discreet3DSImporter::SkipChunk()
{
	Discreet3DS::Chunk psChunk;
	ReadChunk(&psChunk);
	
	stream->IncPtr(psChunk.Size-sizeof(Discreet3DS::Chunk));
	return;
}

// ------------------------------------------------------------------------------------------------
// Process the primary chunk of the file
void Discreet3DSImporter::ParseMainChunk()
{
	ASSIMP_3DS_BEGIN_CHUNK();

	// get chunk type
	switch (chunk.Flag)
	{
	
	case Discreet3DS::CHUNK_PRJ:
		bIsPrj = true;
	case Discreet3DS::CHUNK_MAIN:
		ParseEditorChunk();
		break;
	};

	ASSIMP_3DS_END_CHUNK();
	// recursively continue processing this hierarchy level
	return ParseMainChunk();
}

// ------------------------------------------------------------------------------------------------
void Discreet3DSImporter::ParseEditorChunk()
{
	ASSIMP_3DS_BEGIN_CHUNK();

	// get chunk type
	switch (chunk.Flag)
	{
	case Discreet3DS::CHUNK_OBJMESH:

		ParseObjectChunk();
		break;

	// NOTE: In several documentations in the internet this
	// chunk appears at different locations
	case Discreet3DS::CHUNK_KEYFRAMER:

		ParseKeyframeChunk();
		break;

	case Discreet3DS::CHUNK_VERSION:
		{
		// print the version number
		char buff[10];
		ASSIMP_itoa10(buff,stream->GetI2());
		DefaultLogger::get()->info(std::string("3DS file format version: ") + buff);
		}
		break;
	};
	ASSIMP_3DS_END_CHUNK();
}

// ------------------------------------------------------------------------------------------------
void Discreet3DSImporter::ParseObjectChunk()
{
	ASSIMP_3DS_BEGIN_CHUNK();

	// get chunk type
	switch (chunk.Flag)
	{
	case Discreet3DS::CHUNK_OBJBLOCK:
		{
		unsigned int cnt = 0;
		const char* sz = (const char*)stream->GetPtr();

		// Get the name of the geometry object
		while (stream->GetI1())++cnt;
		ParseChunk(sz,cnt);
		}
		break;

	case Discreet3DS::CHUNK_MAT_MATERIAL:

		// Add a new material to the list
		mScene->mMaterials.push_back(D3DS::Material());
		ParseMaterialChunk();
		break;

	case Discreet3DS::CHUNK_AMBCOLOR:

		// This is the ambient base color of the scene.
		// We add it to the ambient color of all materials
		ParseColorChunk(&mClrAmbient,true);
		if (is_qnan(mClrAmbient.r))
		{
			// We failed to read the ambient base color.
			DefaultLogger::get()->error("3DS: Failed to read ambient base color");
			mClrAmbient.r = mClrAmbient.g = mClrAmbient.b = 0.0f;
		}
		break;

	case Discreet3DS::CHUNK_BIT_MAP:
		{
		// Specifies the background image. The string should already be 
		// properly 0 terminated but we need to be sure
		unsigned int cnt = 0;
		const char* sz = (const char*)stream->GetPtr();
		while (stream->GetI1())++cnt;
		mBackgroundImage = std::string(sz,cnt);
		}
		break;

	case Discreet3DS::CHUNK_BIT_MAP_EXISTS:
		bHasBG = true;
		break;

	case Discreet3DS::CHUNK_MASTER_SCALE:
		// Scene master scaling factor
		mMasterScale = stream->GetF4();
		break;
	};
	ASSIMP_3DS_END_CHUNK();
}

// ------------------------------------------------------------------------------------------------
void Discreet3DSImporter::ParseChunk(const char* name, unsigned int num)
{
	ASSIMP_3DS_BEGIN_CHUNK();

	// IMPLEMENTATION NOTE;
	// Cameras or lights define their transformation in their parent node and in the
	// corresponding light or camera chunks. However, we read and process the latter
	// to to be able to return valid cameras/lights even if no scenegraph is given.

	// get chunk type
	switch (chunk.Flag)
	{
	case Discreet3DS::CHUNK_TRIMESH:
		{
		// this starts a new triangle mesh
		mScene->mMeshes.push_back(D3DS::Mesh());
		D3DS::Mesh& m = mScene->mMeshes.back();

		// Setup the name of the mesh
		m.mName = std::string(name, num);

		// Read mesh chunks
		ParseMeshChunk();
		}
		break;

	case Discreet3DS::CHUNK_LIGHT:	
		{
		// This starts a new light
		aiLight* light = new aiLight();
		mScene->mLights.push_back(light);

		light->mName.Set(std::string(name, num));

		// First read the position of the light
		light->mPosition.x = stream->GetF4();
		light->mPosition.y = stream->GetF4();
		light->mPosition.z = stream->GetF4();

		light->mColorDiffuse = aiColor3D(1.f,1.f,1.f);

		// Now check for further subchunks
		if (!bIsPrj) /* fixme */
			ParseLightChunk();

		// The specular light color is identical the the diffuse light color. The ambient light color
		// is equal to the ambient base color of the whole scene.
		light->mColorSpecular = light->mColorDiffuse;
		light->mColorAmbient  = mClrAmbient;

		if (light->mType == aiLightSource_UNDEFINED)
		{
			// It must be a point light
			light->mType = aiLightSource_POINT;
		}}
		break;

	case Discreet3DS::CHUNK_CAMERA:
		{
		// This starts a new camera
		aiCamera* camera = new aiCamera();
		mScene->mCameras.push_back(camera);
		camera->mName.Set(std::string(name, num));

		// First read the position of the camera
		camera->mPosition.x = stream->GetF4();
		camera->mPosition.y = stream->GetF4();
		camera->mPosition.z = stream->GetF4();

		// Then the camera target
		camera->mLookAt.x = stream->GetF4() - camera->mPosition.x;
		camera->mLookAt.y = stream->GetF4() - camera->mPosition.y;
		camera->mLookAt.z = stream->GetF4() - camera->mPosition.z;
		float len = camera->mLookAt.Length();
		if (len < 1e-5f) {
			
			// There are some files with lookat == position. Don't know why or whether it's ok or not.
			DefaultLogger::get()->error("3DS: Unable to read proper camera look-at vector");
			camera->mLookAt = aiVector3D(0.f,1.f,0.f);

		}
		else camera->mLookAt /= len;

		// And finally - the camera rotation angle, in counter clockwise direction 
		const float angle =  AI_DEG_TO_RAD( stream->GetF4() );
		aiQuaternion quat(camera->mLookAt,angle);
		camera->mUp = quat.GetMatrix() * aiVector3D(0.f,1.f,0.f);

		// Read the lense angle
		camera->mHorizontalFOV = AI_DEG_TO_RAD ( stream->GetF4() );
		if (camera->mHorizontalFOV < 0.001f)  {
			camera->mHorizontalFOV = AI_DEG_TO_RAD(45.f);
		}

		// Now check for further subchunks 
		if (!bIsPrj) /* fixme */ {
			ParseCameraChunk();
		}}
		break;
	};
	ASSIMP_3DS_END_CHUNK();
}

// ------------------------------------------------------------------------------------------------
void Discreet3DSImporter::ParseLightChunk()
{
	ASSIMP_3DS_BEGIN_CHUNK();
	aiLight* light = mScene->mLights.back();

	// get chunk type
	switch (chunk.Flag)
	{
	case Discreet3DS::CHUNK_DL_SPOTLIGHT:
		// Now we can be sure that the light is a spot light
		light->mType = aiLightSource_SPOT;

		// We wouldn't need to normalize here, but we do it
		light->mDirection.x = stream->GetF4() - light->mPosition.x;
		light->mDirection.y = stream->GetF4() - light->mPosition.y;
		light->mDirection.z = stream->GetF4() - light->mPosition.z;
		light->mDirection.Normalize();

		// Now the hotspot and falloff angles - in degrees
		light->mAngleInnerCone = AI_DEG_TO_RAD( stream->GetF4() );

		// FIX: the falloff angle is just an offset
		light->mAngleOuterCone = light->mAngleInnerCone+AI_DEG_TO_RAD( stream->GetF4() );
		break; 

		// intensity multiplier
	case Discreet3DS::CHUNK_DL_MULTIPLIER:
		light->mColorDiffuse = light->mColorDiffuse * stream->GetF4();
		break;

		// light color
	case Discreet3DS::CHUNK_RGBF:
	case Discreet3DS::CHUNK_LINRGBF:
		light->mColorDiffuse.r *= stream->GetF4();
		light->mColorDiffuse.g *= stream->GetF4();
		light->mColorDiffuse.b *= stream->GetF4();
		break;

		// light attenuation
	case Discreet3DS::CHUNK_DL_ATTENUATE: 
		light->mAttenuationLinear = stream->GetF4();
		break;
	};

	ASSIMP_3DS_END_CHUNK();
}

// ------------------------------------------------------------------------------------------------
void Discreet3DSImporter::ParseCameraChunk()
{
	ASSIMP_3DS_BEGIN_CHUNK();
	aiCamera* camera = mScene->mCameras.back();

	// get chunk type
	switch (chunk.Flag)
	{
		// near and far clip plane
	case Discreet3DS::CHUNK_CAM_RANGES:
		camera->mClipPlaneNear = stream->GetF4();
		camera->mClipPlaneFar  = stream->GetF4();
		break;
	}

	ASSIMP_3DS_END_CHUNK();
}

// ------------------------------------------------------------------------------------------------
void Discreet3DSImporter::ParseKeyframeChunk()
{
	ASSIMP_3DS_BEGIN_CHUNK();

	// get chunk type
	switch (chunk.Flag)
	{
	case Discreet3DS::CHUNK_TRACKCAMTGT:
	case Discreet3DS::CHUNK_TRACKSPOTL:
	case Discreet3DS::CHUNK_TRACKCAMERA:
	case Discreet3DS::CHUNK_TRACKINFO:
	case Discreet3DS::CHUNK_TRACKLIGHT:
	case Discreet3DS::CHUNK_TRACKLIGTGT:

		// this starts a new mesh hierarchy chunk
		ParseHierarchyChunk(chunk.Flag);
		break;
	};

	ASSIMP_3DS_END_CHUNK();
}

// ------------------------------------------------------------------------------------------------
// Little helper function for ParseHierarchyChunk
void Discreet3DSImporter::InverseNodeSearch(D3DS::Node* pcNode,D3DS::Node* pcCurrent)
{
	if (!pcCurrent)	{
		mRootNode->push_back(pcNode);
		return;
	}

	if (pcCurrent->mHierarchyPos == pcNode->mHierarchyPos)	{
		if(pcCurrent->mParent) {
			pcCurrent->mParent->push_back(pcNode);
		}
		else pcCurrent->push_back(pcNode);
		return;
	}
	return InverseNodeSearch(pcNode,pcCurrent->mParent);
}

// ------------------------------------------------------------------------------------------------
// Find a node with a specific name in the import hierarchy
D3DS::Node* FindNode(D3DS::Node* root, const std::string& name)
{
	if (root->mName == name)
		return root;
	for (std::vector<D3DS::Node*>::iterator it = root->mChildren.begin();it != root->mChildren.end(); ++it)	{
		D3DS::Node* nd;
		if (( nd = FindNode(*it,name)))
			return nd;
	}
	return NULL;
}

// ------------------------------------------------------------------------------------------------
// Binary predicate for std::unique()
template <class T>
bool KeyUniqueCompare(const T& first, const T& second)
{
	return first.mTime == second.mTime;
}

// ------------------------------------------------------------------------------------------------
// Skip some additional import data.
void Discreet3DSImporter::SkipTCBInfo()
{
	unsigned int flags = stream->GetI2();

	if (!flags)	{
		// Currently we can't do anything with these values. They occur
		// quite rare, so it wouldn't be worth the effort implementing
		// them. 3DS ist not really suitable for complex animations,
		// so full support is not required.
		DefaultLogger::get()->warn("3DS: Skipping TCB animation info");
	}

	if (flags & Discreet3DS::KEY_USE_TENS) {
		stream->IncPtr(4);
	}
	if (flags & Discreet3DS::KEY_USE_BIAS) {
		stream->IncPtr(4);
	}
	if (flags & Discreet3DS::KEY_USE_CONT) {
		stream->IncPtr(4);
	}
	if (flags & Discreet3DS::KEY_USE_EASE_FROM) {
		stream->IncPtr(4);
	}
	if (flags & Discreet3DS::KEY_USE_EASE_TO) {
		stream->IncPtr(4);
	}
}

// ------------------------------------------------------------------------------------------------
// Read hierarchy and keyframe info
void Discreet3DSImporter::ParseHierarchyChunk(uint16_t parent)
{
	ASSIMP_3DS_BEGIN_CHUNK();

	// get chunk type
	switch (chunk.Flag)
	{
	case Discreet3DS::CHUNK_TRACKOBJNAME:

		// This is the name of the object to which the track applies. The chunk also
		// defines the position of this object in the hierarchy.
		{

		// First of all: get the name of the object
		unsigned int cnt = 0;
		const char* sz = (const char*)stream->GetPtr();

		while (stream->GetI1())++cnt;
		std::string name = std::string(sz,cnt);

		// Now find out whether we have this node already (target animation channels 
		// are stored with a separate object ID)
		D3DS::Node* pcNode = FindNode(mRootNode,name);
		int instanceNumber = 1;

		if ( pcNode)
		{
			// if the source is not a CHUNK_TRACKINFO block it wont be an object instance
			if (parent != Discreet3DS::CHUNK_TRACKINFO)
			{
				mCurrentNode = pcNode;
				break;
			}
			pcNode->mInstanceCount++;
			instanceNumber = pcNode->mInstanceCount;
		}
		pcNode = new D3DS::Node();
		pcNode->mName = name;
		pcNode->mInstanceNumber = instanceNumber;

		// There are two unknown values which we can safely ignore
		stream->IncPtr(4);

		// Now read the hierarchy position of the object
		uint16_t hierarchy = stream->GetI2() + 1;
		pcNode->mHierarchyPos   = hierarchy;
		pcNode->mHierarchyIndex = mLastNodeIndex;

		// And find a proper position in the graph for it
		if (mCurrentNode && mCurrentNode->mHierarchyPos == hierarchy)	{

			// add to the parent of the last touched node
			mCurrentNode->mParent->push_back(pcNode);
			mLastNodeIndex++;	
		}
		else if(hierarchy >= mLastNodeIndex)	{

			// place it at the current position in the hierarchy
			mCurrentNode->push_back(pcNode);
			mLastNodeIndex = hierarchy;
		}
		else	{
			// need to go back to the specified position in the hierarchy.
			InverseNodeSearch(pcNode,mCurrentNode);
			mLastNodeIndex++;	
		}
		// Make this node the current node
		mCurrentNode = pcNode;
		}
		break;

	case Discreet3DS::CHUNK_TRACKDUMMYOBJNAME:

		// This is the "real" name of a $$$DUMMY object
		{
			const char* sz = (const char*) stream->GetPtr();
			while (stream->GetI1());

			// If object name is DUMMY, take this one instead
			if (mCurrentNode->mName == "$$$DUMMY")	{
				//DefaultLogger::get()->warn("3DS: Skipping dummy object name for non-dummy object");
				mCurrentNode->mName = std::string(sz);
				break;
			}
		}
		break;

	case Discreet3DS::CHUNK_TRACKPIVOT:

		if ( Discreet3DS::CHUNK_TRACKINFO != parent) 
		{
			DefaultLogger::get()->warn("3DS: Skipping pivot subchunk for non usual object");
			break;
		}

		// Pivot = origin of rotation and scaling
		mCurrentNode->vPivot.x = stream->GetF4();
		mCurrentNode->vPivot.y = stream->GetF4();
		mCurrentNode->vPivot.z = stream->GetF4();
		break;


		// ////////////////////////////////////////////////////////////////////
		// POSITION KEYFRAME
	case Discreet3DS::CHUNK_TRACKPOS:
		{
		stream->IncPtr(10);
		const unsigned int numFrames = stream->GetI4();
		bool sortKeys = false;

		// This could also be meant as the target position for
		// (targeted) lights and cameras
		std::vector<aiVectorKey>* l;
		if ( Discreet3DS::CHUNK_TRACKCAMTGT == parent || Discreet3DS::CHUNK_TRACKLIGTGT == parent)	{
			l = & mCurrentNode->aTargetPositionKeys;
		}
		else l = & mCurrentNode->aPositionKeys;

		l->reserve(numFrames);
		for (unsigned int i = 0; i < numFrames;++i)	{
			const unsigned int fidx = stream->GetI4();

			// Setup a new position key
			aiVectorKey v;
			v.mTime = (double)fidx;

			SkipTCBInfo();
			v.mValue.x = stream->GetF4();
			v.mValue.y = stream->GetF4();
			v.mValue.z = stream->GetF4();

			// check whether we'll need to sort the keys
			if (!l->empty() && v.mTime <= l->back().mTime)
				sortKeys = true;

			// Add the new keyframe to the list
			l->push_back(v);
		}

		// Sort all keys with ascending time values and remove duplicates?
		if (sortKeys)	{
			std::stable_sort(l->begin(),l->end());
			l->erase ( std::unique (l->begin(),l->end(),&KeyUniqueCompare<aiVectorKey>), l->end() );
		}}

		break;

		// ////////////////////////////////////////////////////////////////////
		// CAMERA ROLL KEYFRAME
	case Discreet3DS::CHUNK_TRACKROLL:
		{
		// roll keys are accepted for cameras only
		if (parent != Discreet3DS::CHUNK_TRACKCAMERA)	{
			DefaultLogger::get()->warn("3DS: Ignoring roll track for non-camera object");
			break;
		}
		bool sortKeys = false;
		std::vector<aiFloatKey>* l = &mCurrentNode->aCameraRollKeys;

		stream->IncPtr(10);
		const unsigned int numFrames = stream->GetI4();
		l->reserve(numFrames);
		for (unsigned int i = 0; i < numFrames;++i)	{
			const unsigned int fidx = stream->GetI4();

			// Setup a new position key
			aiFloatKey v;
			v.mTime = (double)fidx;

			// This is just a single float 
			SkipTCBInfo();
			v.mValue = stream->GetF4();

			// Check whether we'll need to sort the keys
			if (!l->empty() && v.mTime <= l->back().mTime)
				sortKeys = true;

			// Add the new keyframe to the list
			l->push_back(v);
		}

		// Sort all keys with ascending time values and remove duplicates?
		if (sortKeys)	{
			std::stable_sort(l->begin(),l->end());
			l->erase ( std::unique (l->begin(),l->end(),&KeyUniqueCompare<aiFloatKey>), l->end() );
		}}
		break;


		// ////////////////////////////////////////////////////////////////////
		// CAMERA FOV KEYFRAME
	case Discreet3DS::CHUNK_TRACKFOV:
		{
			DefaultLogger::get()->error("3DS: Skipping FOV animation track. "
				"This is not supported");
		}
		break;


		// ////////////////////////////////////////////////////////////////////
		// ROTATION KEYFRAME
	case Discreet3DS::CHUNK_TRACKROTATE:
		{
		stream->IncPtr(10);
		const unsigned int numFrames = stream->GetI4();

		bool sortKeys = false;
		std::vector<aiQuatKey>* l = &mCurrentNode->aRotationKeys;
		l->reserve(numFrames);

		for (unsigned int i = 0; i < numFrames;++i)	{
			const unsigned int fidx = stream->GetI4();
			SkipTCBInfo();

			aiQuatKey v;
			v.mTime = (double)fidx;

			// The rotation keyframe is given as an axis-angle pair
			const float rad = stream->GetF4();
			aiVector3D axis;
			axis.x = stream->GetF4();
			axis.y = stream->GetF4();
			axis.z = stream->GetF4();

			if (!axis.x && !axis.y && !axis.z)
				axis.y = 1.f;

			// Construct a rotation quaternion from the axis-angle pair
			v.mValue = aiQuaternion(axis,rad);

			// Check whether we'll need to sort the keys
			if (!l->empty() && v.mTime <= l->back().mTime)
				sortKeys = true;

			// add the new keyframe to the list
			l->push_back(v);
		}
		// Sort all keys with ascending time values and remove duplicates?
		if (sortKeys)	{
			std::stable_sort(l->begin(),l->end());
			l->erase ( std::unique (l->begin(),l->end(),&KeyUniqueCompare<aiQuatKey>), l->end() );
		}}
		break;

		// ////////////////////////////////////////////////////////////////////
		// SCALING KEYFRAME
	case Discreet3DS::CHUNK_TRACKSCALE:
		{
		stream->IncPtr(10);
		const unsigned int numFrames = stream->GetI2();
		stream->IncPtr(2);

		bool sortKeys = false;
		std::vector<aiVectorKey>* l = &mCurrentNode->aScalingKeys;
		l->reserve(numFrames);

		for (unsigned int i = 0; i < numFrames;++i)	{
			const unsigned int fidx = stream->GetI4();
			SkipTCBInfo();

			// Setup a new key
			aiVectorKey v;
			v.mTime = (double)fidx;

			// ... and read its value
			v.mValue.x = stream->GetF4();
			v.mValue.y = stream->GetF4();
			v.mValue.z = stream->GetF4();

			// check whether we'll need to sort the keys
			if (!l->empty() && v.mTime <= l->back().mTime)
				sortKeys = true;
			
			// Remove zero-scalings on singular axes - they've been reported to be there erroneously in some strange files
			if (!v.mValue.x) v.mValue.x = 1.f;
			if (!v.mValue.y) v.mValue.y = 1.f;
			if (!v.mValue.z) v.mValue.z = 1.f;

			l->push_back(v);
		}
		// Sort all keys with ascending time values and remove duplicates?
		if (sortKeys)	{
			std::stable_sort(l->begin(),l->end());
			l->erase ( std::unique (l->begin(),l->end(),&KeyUniqueCompare<aiVectorKey>), l->end() );
		}}
		break;
	};

	ASSIMP_3DS_END_CHUNK();
}

// ------------------------------------------------------------------------------------------------
// Read a face chunk - it contains smoothing groups and material assignments
void Discreet3DSImporter::ParseFaceChunk()
{
	ASSIMP_3DS_BEGIN_CHUNK();

	// Get the mesh we're currently working on
	D3DS::Mesh& mMesh = mScene->mMeshes.back();

	// Get chunk type
	switch (chunk.Flag)
	{
	case Discreet3DS::CHUNK_SMOOLIST:
		{
		// This is the list of smoothing groups - a bitfield for every face. 
		// Up to 32 smoothing groups assigned to a single face.
		unsigned int num = chunkSize/4, m = 0;
		for (std::vector<D3DS::Face>::iterator i =  mMesh.mFaces.begin(); m != num;++i, ++m)	{
			// nth bit is set for nth smoothing group
			(*i).iSmoothGroup = stream->GetI4();
		}}
		break;

	case Discreet3DS::CHUNK_FACEMAT:
		{
		// at fist an asciiz with the material name
		const char* sz = (const char*)stream->GetPtr();
		while (stream->GetI1());

		// find the index of the material
		unsigned int idx = 0xcdcdcdcd, cnt = 0;
		for (std::vector<D3DS::Material>::const_iterator i =  mScene->mMaterials.begin();i != mScene->mMaterials.end();++i,++cnt)	{
			// use case independent comparisons. hopefully it will work.
			if ((*i).mName.length() && !ASSIMP_stricmp(sz, (*i).mName.c_str()))	{
				idx = cnt;
				break;
			}
		}
		if (0xcdcdcdcd == idx)	{
			DefaultLogger::get()->error(std::string("3DS: Unknown material: ") + sz);
		}

		// Now continue and read all material indices
		cnt = (uint16_t)stream->GetI2();
		for (unsigned int i = 0; i < cnt;++i)	{
			unsigned int fidx = (uint16_t)stream->GetI2();

			// check range
			if (fidx >= mMesh.mFaceMaterials.size())	{
				DefaultLogger::get()->error("3DS: Invalid face index in face material list");
			}
			else mMesh.mFaceMaterials[fidx] = idx;
		}}
		break;
	};
	ASSIMP_3DS_END_CHUNK();
}

// ------------------------------------------------------------------------------------------------
// Read a mesh chunk. Here's the actual mesh data
void Discreet3DSImporter::ParseMeshChunk()
{
	ASSIMP_3DS_BEGIN_CHUNK();

	// Get the mesh we're currently working on
	D3DS::Mesh& mMesh = mScene->mMeshes.back();

	// get chunk type
	switch (chunk.Flag)
	{
	case Discreet3DS::CHUNK_VERTLIST:
		{
		// This is the list of all vertices in the current mesh
		int num = (int)(uint16_t)stream->GetI2();
		mMesh.mPositions.reserve(num);
		while (num-- > 0)	{
			aiVector3D v;
			v.x = stream->GetF4();
			v.y = stream->GetF4();
			v.z = stream->GetF4();
			mMesh.mPositions.push_back(v);
		}}
		break;
	case Discreet3DS::CHUNK_TRMATRIX:
		{
		// This is the RLEATIVE transformation matrix of the current mesh. Vertices are
		// pretransformed by this matrix wonder.
		mMesh.mMat.a1 = stream->GetF4();
		mMesh.mMat.b1 = stream->GetF4();
		mMesh.mMat.c1 = stream->GetF4();
		mMesh.mMat.a2 = stream->GetF4();
		mMesh.mMat.b2 = stream->GetF4();
		mMesh.mMat.c2 = stream->GetF4();
		mMesh.mMat.a3 = stream->GetF4();
		mMesh.mMat.b3 = stream->GetF4();
		mMesh.mMat.c3 = stream->GetF4();
		mMesh.mMat.a4 = stream->GetF4();
		mMesh.mMat.b4 = stream->GetF4();
		mMesh.mMat.c4 = stream->GetF4();
		}
		break;

	case Discreet3DS::CHUNK_MAPLIST:
		{
		// This is the list of all UV coords in the current mesh
		int num = (int)(uint16_t)stream->GetI2();
		mMesh.mTexCoords.reserve(num);
		while (num-- > 0)	{
			aiVector3D v;
			v.x = stream->GetF4();
			v.y = stream->GetF4();
			mMesh.mTexCoords.push_back(v);
		}}
		break;

	case Discreet3DS::CHUNK_FACELIST:
		{
		// This is the list of all faces in the current mesh
		int num = (int)(uint16_t)stream->GetI2();
		mMesh.mFaces.reserve(num);
		while (num-- > 0)	{
			// 3DS faces are ALWAYS triangles
			mMesh.mFaces.push_back(D3DS::Face());
			D3DS::Face& sFace = mMesh.mFaces.back();

			sFace.mIndices[0] = (uint16_t)stream->GetI2();
			sFace.mIndices[1] = (uint16_t)stream->GetI2();
			sFace.mIndices[2] = (uint16_t)stream->GetI2();

			stream->IncPtr(2); // skip edge visibility flag
		}

		// Resize the material array (0xcdcdcdcd marks the default material; so if a face is 
		// not referenced by a material, $$DEFAULT will be assigned to it)
		mMesh.mFaceMaterials.resize(mMesh.mFaces.size(),0xcdcdcdcd);

		// Larger 3DS files could have multiple FACE chunks here
		chunkSize = stream->GetRemainingSizeToLimit();
		if ( chunkSize > (int) sizeof(Discreet3DS::Chunk ) )
			ParseFaceChunk();
		}
		break;
	};
	ASSIMP_3DS_END_CHUNK();
}

// ------------------------------------------------------------------------------------------------
// Read a 3DS material chunk
void Discreet3DSImporter::ParseMaterialChunk()
{
	ASSIMP_3DS_BEGIN_CHUNK();
	switch (chunk.Flag)
	{
	case Discreet3DS::CHUNK_MAT_MATNAME:

		{
		// The material name string is already zero-terminated, but we need to be sure ...
		const char* sz = (const char*)stream->GetPtr();
		unsigned int cnt = 0;
		while (stream->GetI1())
			++cnt;

		if (!cnt)	{
			// This may not be, we use the default name instead
			DefaultLogger::get()->error("3DS: Empty material name");
		}
		else mScene->mMaterials.back().mName = std::string(sz,cnt);
		}
		break;

	case Discreet3DS::CHUNK_MAT_DIFFUSE:
		{
		// This is the diffuse material color
		aiColor3D* pc = &mScene->mMaterials.back().mDiffuse;
		ParseColorChunk(pc);
		if (is_qnan(pc->r))	{
			// color chunk is invalid. Simply ignore it
			DefaultLogger::get()->error("3DS: Unable to read DIFFUSE chunk");
			pc->r = pc->g = pc->b = 1.0f;
		}}
		break;

	case Discreet3DS::CHUNK_MAT_SPECULAR:
		{
		// This is the specular material color
		aiColor3D* pc = &mScene->mMaterials.back().mSpecular;
		ParseColorChunk(pc);
		if (is_qnan(pc->r))	{
			// color chunk is invalid. Simply ignore it
			DefaultLogger::get()->error("3DS: Unable to read SPECULAR chunk");
			pc->r = pc->g = pc->b = 1.0f;
		}}
		break;

	case Discreet3DS::CHUNK_MAT_AMBIENT:
		{
		// This is the ambient material color
		aiColor3D* pc = &mScene->mMaterials.back().mAmbient;
		ParseColorChunk(pc);
		if (is_qnan(pc->r))	{
			// color chunk is invalid. Simply ignore it
			DefaultLogger::get()->error("3DS: Unable to read AMBIENT chunk");
			pc->r = pc->g = pc->b = 0.0f;
		}}
		break;

	case Discreet3DS::CHUNK_MAT_SELF_ILLUM:
		{
		// This is the emissive material color
		aiColor3D* pc = &mScene->mMaterials.back().mEmissive;
		ParseColorChunk(pc);
		if (is_qnan(pc->r))	{
			// color chunk is invalid. Simply ignore it
			DefaultLogger::get()->error("3DS: Unable to read EMISSIVE chunk");
			pc->r = pc->g = pc->b = 0.0f;
		}}
		break;

	case Discreet3DS::CHUNK_MAT_TRANSPARENCY:
		{
		// This is the material's transparency
		float* pcf = &mScene->mMaterials.back().mTransparency;
		*pcf = ParsePercentageChunk();

		// NOTE: transparency, not opacity
		if (is_qnan(*pcf))
			*pcf = 1.0f;
		else *pcf = 1.0f - *pcf * (float)0xFFFF / 100.0f;
		}
		break;

	case Discreet3DS::CHUNK_MAT_SHADING:
		// This is the material shading mode
		mScene->mMaterials.back().mShading = (D3DS::Discreet3DS::shadetype3ds)stream->GetI2();
		break;

	case Discreet3DS::CHUNK_MAT_TWO_SIDE:
		// This is the two-sided flag
		mScene->mMaterials.back().mTwoSided = true;
		break;

	case Discreet3DS::CHUNK_MAT_SHININESS:
		{ // This is the shininess of the material
		float* pcf = &mScene->mMaterials.back().mSpecularExponent;
		*pcf = ParsePercentageChunk();
		if (is_qnan(*pcf))
			*pcf = 0.0f;
		else *pcf *= (float)0xFFFF;
		}
		break;

	case Discreet3DS::CHUNK_MAT_SHININESS_PERCENT:
		{ // This is the shininess strength of the material
		float* pcf = &mScene->mMaterials.back().mShininessStrength;
		*pcf = ParsePercentageChunk();
		if (is_qnan(*pcf))
			*pcf = 0.0f;
		else *pcf *= (float)0xffff / 100.0f;
		}
		break;

	case Discreet3DS::CHUNK_MAT_SELF_ILPCT:
		{ // This is the self illumination strength of the material
		float f = ParsePercentageChunk();
		if (is_qnan(f))
			f = 0.0f;
		else f *= (float)0xFFFF / 100.0f;
		mScene->mMaterials.back().mEmissive = aiColor3D(f,f,f);
		}
		break;

	// Parse texture chunks
	case Discreet3DS::CHUNK_MAT_TEXTURE:
		// Diffuse texture
		ParseTextureChunk(&mScene->mMaterials.back().sTexDiffuse);
		break;
	case Discreet3DS::CHUNK_MAT_BUMPMAP:
		// Height map
		ParseTextureChunk(&mScene->mMaterials.back().sTexBump);
		break;
	case Discreet3DS::CHUNK_MAT_OPACMAP:
		// Opacity texture
		ParseTextureChunk(&mScene->mMaterials.back().sTexOpacity);
		break;
	case Discreet3DS::CHUNK_MAT_MAT_SHINMAP:
		// Shininess map
		ParseTextureChunk(&mScene->mMaterials.back().sTexShininess);
		break;
	case Discreet3DS::CHUNK_MAT_SPECMAP:
		// Specular map
		ParseTextureChunk(&mScene->mMaterials.back().sTexSpecular);
		break;
	case Discreet3DS::CHUNK_MAT_SELFIMAP:
		// Self-illumination (emissive) map
		ParseTextureChunk(&mScene->mMaterials.back().sTexEmissive);
		break;
	case Discreet3DS::CHUNK_MAT_REFLMAP:
		// Reflection map
		ParseTextureChunk(&mScene->mMaterials.back().sTexReflective);
		break;
	};
	ASSIMP_3DS_END_CHUNK();
}

// ------------------------------------------------------------------------------------------------
void Discreet3DSImporter::ParseTextureChunk(D3DS::Texture* pcOut)
{
	ASSIMP_3DS_BEGIN_CHUNK();

	// get chunk type
	switch (chunk.Flag)
	{
	case Discreet3DS::CHUNK_MAPFILE:
		{
		// The material name string is already zero-terminated, but we need to be sure ...
		const char* sz = (const char*)stream->GetPtr();
		unsigned int cnt = 0;
		while (stream->GetI1())
			++cnt;
		pcOut->mMapName = std::string(sz,cnt);
		}
		break;


	case Discreet3DS::CHUNK_PERCENTF:
		// Manually parse the blend factor
		pcOut->mTextureBlend = stream->GetF4();
		break;

	case Discreet3DS::CHUNK_PERCENTW:
		// Manually parse the blend factor
		pcOut->mTextureBlend = (float)((uint16_t)stream->GetI2()) / 100.0f;
		break;

	case Discreet3DS::CHUNK_MAT_MAP_USCALE:
		// Texture coordinate scaling in the U direction
		pcOut->mScaleU = stream->GetF4();
		if (0.0f == pcOut->mScaleU)
		{
			DefaultLogger::get()->warn("Texture coordinate scaling in the x direction is zero. Assuming 1.");
			pcOut->mScaleU = 1.0f;
		}
		break;
	case Discreet3DS::CHUNK_MAT_MAP_VSCALE:
		// Texture coordinate scaling in the V direction
		pcOut->mScaleV = stream->GetF4();
		if (0.0f == pcOut->mScaleV)
		{
			DefaultLogger::get()->warn("Texture coordinate scaling in the y direction is zero. Assuming 1.");
			pcOut->mScaleV = 1.0f;
		}
		break;

	case Discreet3DS::CHUNK_MAT_MAP_UOFFSET:
		// Texture coordinate offset in the U direction
		pcOut->mOffsetU = -stream->GetF4();
		break;

	case Discreet3DS::CHUNK_MAT_MAP_VOFFSET:
		// Texture coordinate offset in the V direction
		pcOut->mOffsetV = stream->GetF4();
		break;

	case Discreet3DS::CHUNK_MAT_MAP_ANG:
		// Texture coordinate rotation, CCW in DEGREES
		pcOut->mRotation = -AI_DEG_TO_RAD( stream->GetF4() );
		break;

	case Discreet3DS::CHUNK_MAT_MAP_TILING:
		{
		const uint16_t iFlags = stream->GetI2();

		// Get the mapping mode (for both axes)
		if (iFlags & 0x2u)
			pcOut->mMapMode = aiTextureMapMode_Mirror;
		
		else if (iFlags & 0x10u)
			pcOut->mMapMode = aiTextureMapMode_Decal;
		
		// wrapping in all remaining cases
		else pcOut->mMapMode = aiTextureMapMode_Wrap;
		}
		break;
	};

	ASSIMP_3DS_END_CHUNK();
}

// ------------------------------------------------------------------------------------------------
// Read a percentage chunk
float Discreet3DSImporter::ParsePercentageChunk()
{
	Discreet3DS::Chunk chunk;
	ReadChunk(&chunk);

	if (Discreet3DS::CHUNK_PERCENTF == chunk.Flag)
		return stream->GetF4();
	else if (Discreet3DS::CHUNK_PERCENTW == chunk.Flag)
		return (float)((uint16_t)stream->GetI2()) / (float)0xFFFF;
	return get_qnan();
}

// ------------------------------------------------------------------------------------------------
// Read a color chunk. If a percentage chunk is found instead it is read as a grayscale color
void Discreet3DSImporter::ParseColorChunk(aiColor3D* out,
	bool acceptPercent)
{
	ai_assert(out != NULL);

	// error return value
	const float qnan = get_qnan();
	static const aiColor3D clrError = aiColor3D(qnan,qnan,qnan);

	Discreet3DS::Chunk chunk;
	ReadChunk(&chunk);
	const unsigned int diff = chunk.Size - sizeof(Discreet3DS::Chunk);

	bool bGamma = false;

	// Get the type of the chunk
	switch(chunk.Flag)
	{
	case Discreet3DS::CHUNK_LINRGBF:
		bGamma = true;

	case Discreet3DS::CHUNK_RGBF:
		if (sizeof(float) * 3 > diff)	{
			*out = clrError;
			return;
		}
		out->r = stream->GetF4();
		out->g = stream->GetF4();
		out->b = stream->GetF4();
		break;

	case Discreet3DS::CHUNK_LINRGBB:
		bGamma = true;
	case Discreet3DS::CHUNK_RGBB:
		if (sizeof(char) * 3 > diff)	{
			*out = clrError;
			return;
		}
		out->r = (float)(uint8_t)stream->GetI1() / 255.0f;
		out->g = (float)(uint8_t)stream->GetI1() / 255.0f;
		out->b = (float)(uint8_t)stream->GetI1() / 255.0f;
		break;

	// Percentage chunks are accepted, too.
	case Discreet3DS::CHUNK_PERCENTF:
		if (acceptPercent && 4 <= diff)	{
			out->g = out->b = out->r = stream->GetF4();
			break;
		}
		*out = clrError;
		return;

	case Discreet3DS::CHUNK_PERCENTW:
		if (acceptPercent && 1 <= diff)	{
			out->g = out->b = out->r = (float)(uint8_t)stream->GetI1() / 255.0f;
			break;
		}
		*out = clrError;
		return;

	default:
		stream->IncPtr(diff);
		// Skip unknown chunks, hope this won't cause any problems.
		return ParseColorChunk(out,acceptPercent);
	};
	(void)bGamma;
}

#endif // !! ASSIMP_BUILD_NO_3DS_IMPORTER