assimp/code/LWOMaterial.cpp

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

/** @file Implementation of the material oart of the LWO importer class */


#include "AssimpPCH.h"
#ifndef ASSIMP_BUILD_NO_LWO_IMPORTER

// internal headers
#include "LWOLoader.h"
#include "MaterialSystem.h"
#include "ByteSwap.h"

using namespace Assimp;

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

// ------------------------------------------------------------------------------------------------
// Convert a lightwave mapping mode to our's
inline aiTextureMapMode GetMapMode(LWO::Texture::Wrap in)
{
	switch (in)
	{	
		case LWO::Texture::REPEAT:
			return aiTextureMapMode_Wrap;

		case LWO::Texture::MIRROR:
			return aiTextureMapMode_Mirror;

		case LWO::Texture::RESET:
			DefaultLogger::get()->warn("LWO2: Unsupported texture map mode: RESET");

			// fall though here
		case LWO::Texture::EDGE:
			return aiTextureMapMode_Clamp;
	}
	return (aiTextureMapMode)0;
}

// ------------------------------------------------------------------------------------------------
bool LWOImporter::HandleTextures(MaterialHelper* pcMat, const TextureList& in, aiTextureType type)
{
	ai_assert(NULL != pcMat);

	unsigned int cur = 0, temp = 0;
	aiString s;
	bool ret = false;

	for (TextureList::const_iterator it = in.begin(), end = in.end();it != end;++it)	{
		if (!(*it).enabled || !(*it).bCanUse)
			continue;
		ret = true;

		// Convert lightwave's mapping modes to ours. We let them
		// as they are, the GenUVcoords step will compute UV 
		// channels if they're not there.

		aiTextureMapping mapping;
		switch ((*it).mapMode)
		{
			case LWO::Texture::Planar:
				mapping = aiTextureMapping_PLANE;
				break;
			case LWO::Texture::Cylindrical:
				mapping = aiTextureMapping_CYLINDER;
				break;
			case LWO::Texture::Spherical:
				mapping = aiTextureMapping_SPHERE;
				break;
			case LWO::Texture::Cubic:
				mapping = aiTextureMapping_BOX;
				break;
			case LWO::Texture::FrontProjection:
				DefaultLogger::get()->error("LWO2: Unsupported texture mapping: FrontProjection");
				mapping = aiTextureMapping_OTHER;
				break;
			case LWO::Texture::UV:
				{
					if( 0xffffffff == (*it).mRealUVIndex )	{
						// We have no UV index for this texture, so we can't display it
						continue;
					}

					// add the UV source index
					temp = (*it).mRealUVIndex;
					pcMat->AddProperty<int>((int*)&temp,1,AI_MATKEY_UVWSRC(type,cur));

					mapping = aiTextureMapping_UV;
				}
				break;
		};

		if (mapping != aiTextureMapping_UV)	{
			// Setup the main axis 
			aiVector3D v;
			switch ((*it).majorAxis)	{
				case Texture::AXIS_X:
					v = aiVector3D(1.f,0.f,0.f);
					break;
				case Texture::AXIS_Y:
					v = aiVector3D(0.f,1.f,0.f);
					break;
				default: // case Texture::AXIS_Z:
					v = aiVector3D(0.f,0.f,1.f);
					break;
			}

			pcMat->AddProperty(&v,1,AI_MATKEY_TEXMAP_AXIS(type,cur));

			// Setup UV scalings for cylindric and spherical projections
			if (mapping == aiTextureMapping_CYLINDER || mapping == aiTextureMapping_SPHERE)	{
				aiUVTransform trafo;
				trafo.mScaling.x = (*it).wrapAmountW;
				trafo.mScaling.y = (*it).wrapAmountH;

				pcMat->AddProperty((float*)&trafo,sizeof(aiUVTransform),AI_MATKEY_UVTRANSFORM(type,cur));
			}
			DefaultLogger::get()->debug("LWO2: Setting up non-UV mapping");
		}

		// The older LWOB format does not use indirect references to clips.
		// The file name of a texture is directly specified in the tex chunk.
		if (mIsLWO2)	{
			// find the corresponding clip
			ClipList::iterator clip = mClips.begin();
			temp = (*it).mClipIdx;
			for (ClipList::iterator end = mClips.end(); clip != end; ++clip)	{
				if ((*clip).idx == temp)
					break;
				
			}
			if (mClips.end() == clip)	{
				DefaultLogger::get()->error("LWO2: Clip index is out of bounds");
				temp = 0;

				// fixme: appearently some LWO files shipping with Doom3 don't
				// have clips at all ... check whether that's true or whether
				// it's a bug in the loader.

				s.Set("$texture.png");

				//continue;
			}
			else {
				if (Clip::UNSUPPORTED == (*clip).type)	{
					DefaultLogger::get()->error("LWO2: Clip type is not supported");
					continue;
				}
				AdjustTexturePath((*clip).path);
				s.Set((*clip).path);

				// Additional image settings
				int flags = 0;
				if ((*clip).negate) {
					flags |= aiTextureFlags_Invert;
				}
				pcMat->AddProperty(&flags,1,AI_MATKEY_TEXFLAGS(type,cur));
			}
		}
		else 
		{
			std::string ss = (*it).mFileName;
			if (!ss.length()) {
				DefaultLogger::get()->error("LWOB: Empty file name");
				continue;
			}
			AdjustTexturePath(ss);
			s.Set(ss);
		}
		pcMat->AddProperty(&s,AI_MATKEY_TEXTURE(type,cur));

		// add the blend factor
		pcMat->AddProperty<float>(&(*it).mStrength,1,AI_MATKEY_TEXBLEND(type,cur));

		// add the blend operation
		switch ((*it).blendType)
		{
			case LWO::Texture::Normal:
			case LWO::Texture::Multiply:
				temp = (unsigned int)aiTextureOp_Multiply;
				break;

			case LWO::Texture::Subtractive:
			case LWO::Texture::Difference:
				temp = (unsigned int)aiTextureOp_Subtract;
				break;

			case LWO::Texture::Divide:
				temp = (unsigned int)aiTextureOp_Divide;
				break;

			case LWO::Texture::Additive:
				temp = (unsigned int)aiTextureOp_Add;
				break;

			default:
				temp = (unsigned int)aiTextureOp_Multiply;
				DefaultLogger::get()->warn("LWO2: Unsupported texture blend mode: alpha or displacement");

		}
		// Setup texture operation
		pcMat->AddProperty<int>((int*)&temp,1,AI_MATKEY_TEXOP(type,cur));

		// setup the mapping mode
		pcMat->AddProperty<int>((int*)&mapping,1,AI_MATKEY_MAPPING(type,cur));

		// add the u-wrapping
		temp = (unsigned int)GetMapMode((*it).wrapModeWidth);
		pcMat->AddProperty<int>((int*)&temp,1,AI_MATKEY_MAPPINGMODE_U(type,cur));

		// add the v-wrapping
		temp = (unsigned int)GetMapMode((*it).wrapModeHeight);
		pcMat->AddProperty<int>((int*)&temp,1,AI_MATKEY_MAPPINGMODE_V(type,cur));

		++cur;
	}
	return ret;
}

// ------------------------------------------------------------------------------------------------
void LWOImporter::ConvertMaterial(const LWO::Surface& surf,MaterialHelper* pcMat)
{
	// copy the name of the surface
	aiString st;
	st.Set(surf.mName);
	pcMat->AddProperty(&st,AI_MATKEY_NAME);

	const int i = surf.bDoubleSided ? 1 : 0;
	pcMat->AddProperty(&i,1,AI_MATKEY_TWOSIDED);

	// add the refraction index and the bump intensity
	pcMat->AddProperty(&surf.mIOR,1,AI_MATKEY_REFRACTI);
	pcMat->AddProperty(&surf.mBumpIntensity,1,AI_MATKEY_BUMPSCALING);
	
	aiShadingMode m;
	if (surf.mSpecularValue && surf.mGlossiness)
	{
		float fGloss;
		if (mIsLWO2)	{
			fGloss = pow( surf.mGlossiness*10.0f+2.0f, 2.0f);
		}
		else
		{
			if (16.0f >= surf.mGlossiness)
				fGloss = 6.0f;
			else if (64.0f >= surf.mGlossiness)
				fGloss = 20.0f;
			else if (256.0f >= surf.mGlossiness)
				fGloss = 50.0f;
			else fGloss = 80.0f;
		}

		pcMat->AddProperty(&surf.mSpecularValue,1,AI_MATKEY_SHININESS_STRENGTH);
		pcMat->AddProperty(&fGloss,1,AI_MATKEY_SHININESS);
		m = aiShadingMode_Phong;
	}
	else m = aiShadingMode_Gouraud;

	// specular color
	aiColor3D clr = lerp( aiColor3D(1.f,1.f,1.f), surf.mColor, surf.mColorHighlights );
	pcMat->AddProperty(&clr,1,AI_MATKEY_COLOR_SPECULAR);
	pcMat->AddProperty(&surf.mSpecularValue,1,AI_MATKEY_SHININESS_STRENGTH);

	// emissive color
	// luminosity is not really the same but it affects the surface in a similar way. Some scaling looks good.
	clr.g = clr.b = clr.r = surf.mLuminosity*0.8f;
	pcMat->AddProperty<aiColor3D>(&clr,1,AI_MATKEY_COLOR_EMISSIVE);

	// opacity ... either additive or default-blended, please
	if (0.f != surf.mAdditiveTransparency)	{

		const int add = aiBlendMode_Additive;
		pcMat->AddProperty(&surf.mAdditiveTransparency,1,AI_MATKEY_OPACITY);
		pcMat->AddProperty(&add,1,AI_MATKEY_BLEND_FUNC);
	}

	else if (10e10f != surf.mTransparency)	{
		const int def = aiBlendMode_Default;
		const float f = 1.0f-surf.mTransparency;
		pcMat->AddProperty(&f,1,AI_MATKEY_OPACITY);
		pcMat->AddProperty(&def,1,AI_MATKEY_BLEND_FUNC);
	}
	

	// ADD TEXTURES to the material
	// TODO: find out how we can handle COLOR textures correctly...
	bool b = HandleTextures(pcMat,surf.mColorTextures,aiTextureType_DIFFUSE);
	b = (b || HandleTextures(pcMat,surf.mDiffuseTextures,aiTextureType_DIFFUSE));
	HandleTextures(pcMat,surf.mSpecularTextures,aiTextureType_SPECULAR);
	HandleTextures(pcMat,surf.mGlossinessTextures,aiTextureType_SHININESS);
	HandleTextures(pcMat,surf.mBumpTextures,aiTextureType_HEIGHT);
	HandleTextures(pcMat,surf.mOpacityTextures,aiTextureType_OPACITY);
	HandleTextures(pcMat,surf.mReflectionTextures,aiTextureType_REFLECTION);

	// Now we need to know which shader to use .. iterate through the shader list of
	// the surface and  search for a name which we know ... 
	for (ShaderList::const_iterator it = surf.mShaders.begin(), end = surf.mShaders.end();it != end;++it)	{
		//if (!(*it).enabled)continue;

		if ((*it).functionName == "LW_SuperCelShader" || (*it).functionName == "AH_CelShader")	{
			DefaultLogger::get()->info("LWO2: Mapping LW_SuperCelShader/AH_CelShader to aiShadingMode_Toon");

			m = aiShadingMode_Toon;
			break;
		}
		else if ((*it).functionName == "LW_RealFresnel" || (*it).functionName == "LW_FastFresnel")	{
			DefaultLogger::get()->info("LWO2: Mapping LW_RealFresnel/LW_FastFresnel to aiShadingMode_Fresnel");

			m = aiShadingMode_Fresnel;
			break;
		}
		else
		{
			DefaultLogger::get()->warn("LWO2: Unknown surface shader: " + (*it).functionName);
		}
	}
	if (surf.mMaximumSmoothAngle <= 0.0f)
		m = aiShadingMode_Flat;
	pcMat->AddProperty((int*)&m,1,AI_MATKEY_SHADING_MODEL);

	// (the diffuse value is just a scaling factor)
	// If a diffuse texture is set, we set this value to 1.0
	clr = (b && false ? aiColor3D(1.f,1.f,1.f) : surf.mColor);
	clr.r *= surf.mDiffuseValue;
	clr.g *= surf.mDiffuseValue;
	clr.b *= surf.mDiffuseValue;
	pcMat->AddProperty<aiColor3D>(&clr,1,AI_MATKEY_COLOR_DIFFUSE);
}

// ------------------------------------------------------------------------------------------------
char LWOImporter::FindUVChannels(LWO::TextureList& list,
	LWO::Layer& layer,LWO::UVChannel& uv, unsigned int next)
{
	char ret = 0;
	for (TextureList::iterator it = list.begin(), end = list.end();it != end;++it)	{

		// Ignore textures with non-UV mappings for the moment.
		if (!(*it).enabled || !(*it).bCanUse || (*it).mapMode != LWO::Texture::UV)	{
			continue;
		}
		
		if ((*it).mUVChannelIndex == uv.name) {
			ret = 1;
		
			// got it.
			if ((*it).mRealUVIndex == 0xffffffff || (*it).mRealUVIndex == next)
			{
				(*it).mRealUVIndex = next;
			}
			else {
				// channel mismatch. need to duplicate the material.
				DefaultLogger::get()->warn("LWO: Channel mismatch, would need to duplicate surface [design bug]");

				// TODO
			}
		}
	}
	return ret;
}

// ------------------------------------------------------------------------------------------------
void LWOImporter::FindUVChannels(LWO::Surface& surf, 
	LWO::SortedRep& sorted,LWO::Layer& layer,
	unsigned int out[AI_MAX_NUMBER_OF_TEXTURECOORDS])
{
	unsigned int next = 0, extra = 0, num_extra = 0;

	// Check whether we have an UV entry != 0 for one of the faces in 'sorted'
	for (unsigned int i = 0; i < layer.mUVChannels.size();++i)	{
		LWO::UVChannel& uv = layer.mUVChannels[i];

		for (LWO::SortedRep::const_iterator it = sorted.begin(); it != sorted.end(); ++it)	{
			
			LWO::Face& face = layer.mFaces[*it];

			for (unsigned int n = 0; n < face.mNumIndices; ++n) {
				unsigned int idx = face.mIndices[n];

				if (uv.abAssigned[idx] && ((aiVector2D*)&uv.rawData[0])[idx] != aiVector2D()) {

					if (next >= AI_MAX_NUMBER_OF_TEXTURECOORDS) {

						DefaultLogger::get()->error("LWO: Maximum number of UV channels for "
							"this mesh reached. Skipping channel \'" + uv.name + "\'");

					}
					else {
						// Search through all textures assigned to 'surf' and look for this UV channel
						char had = 0;
						had |= FindUVChannels(surf.mColorTextures,layer,uv,next);
						had |= FindUVChannels(surf.mDiffuseTextures,layer,uv,next);
						had |= FindUVChannels(surf.mSpecularTextures,layer,uv,next);
						had |= FindUVChannels(surf.mGlossinessTextures,layer,uv,next);
						had |= FindUVChannels(surf.mOpacityTextures,layer,uv,next);
						had |= FindUVChannels(surf.mBumpTextures,layer,uv,next);
						had |= FindUVChannels(surf.mReflectionTextures,layer,uv,next);

						if (had != 0) {
							
							// We have a texture referencing this UV channel so we have to take special care of it
							if (num_extra) {
							
								for (unsigned int a = next; a < std::min( extra, AI_MAX_NUMBER_OF_TEXTURECOORDS-1u ); ++a) {								
									out[a+1] = out[a];
								}
							}
							++extra;
							out[next++] = i;
						}
						else {
						
							// B<>h ... seems not to be used at all. Push to end if enough space is available.
							out[extra++] = i;
							++num_extra;
						}
					}
					it = sorted.end()-1;
					break;
				}
			}
		}
	}
	if (next != AI_MAX_NUMBER_OF_TEXTURECOORDS) {
		out[extra] = 0xffffffff;
	}
}

// ------------------------------------------------------------------------------------------------
void LWOImporter::FindVCChannels(const LWO::Surface& surf, LWO::SortedRep& sorted, const LWO::Layer& layer,
	unsigned int out[AI_MAX_NUMBER_OF_COLOR_SETS])
{
	unsigned int next = 0;

	// Check whether we have an vc entry != 0 for one of the faces in 'sorted'
	for (unsigned int i = 0; i < layer.mVColorChannels.size();++i)	{
		const LWO::VColorChannel& vc = layer.mVColorChannels[i];

		if (surf.mVCMap == vc.name) {
			// The vertex color map is explicitely requested by the surface so we need to take special care of it
			for (unsigned int a = 0; a < std::min(next,AI_MAX_NUMBER_OF_COLOR_SETS-1u); ++a) {
				out[a+1] = out[a];
			}
			out[0] = i;
			++next;
		}
		else {

			for (LWO::SortedRep::iterator it = sorted.begin(); it != sorted.end(); ++it)	{
				const LWO::Face& face = layer.mFaces[*it];

				for (unsigned int n = 0; n < face.mNumIndices; ++n) {
					unsigned int idx = face.mIndices[n];

					if (vc.abAssigned[idx] && ((aiColor4D*)&vc.rawData[0])[idx] != aiColor4D(0.f,0.f,0.f,1.f)) {
						if (next >= AI_MAX_NUMBER_OF_COLOR_SETS) {

							DefaultLogger::get()->error("LWO: Maximum number of vertex color channels for "
								"this mesh reached. Skipping channel \'" + vc.name + "\'");

						}
						else {
							out[next++] = i;
						}
						it = sorted.end()-1;
						break;
					}
				}
			}
		}
	}
	if (next != AI_MAX_NUMBER_OF_COLOR_SETS) {
		out[next] = 0xffffffff;
	}
}

// ------------------------------------------------------------------------------------------------
void LWOImporter::LoadLWO2ImageMap(unsigned int size, LWO::Texture& tex )
{
	LE_NCONST uint8_t* const end = mFileBuffer + size;
	while (true)
	{
		if (mFileBuffer + 6 >= end)break;
		LE_NCONST IFF::SubChunkHeader* const head = IFF::LoadSubChunk(mFileBuffer);

		if (mFileBuffer + head->length > end)
			throw new ImportErrorException("LWO2: Invalid SURF.BLOCK chunk length");

		uint8_t* const next = mFileBuffer+head->length;
		switch (head->type)
		{
		case AI_LWO_PROJ:
			tex.mapMode = (Texture::MappingMode)GetU2();
			break;
		case AI_LWO_WRAP:
			tex.wrapModeWidth  = (Texture::Wrap)GetU2();
			tex.wrapModeHeight = (Texture::Wrap)GetU2();
			break;
		case AI_LWO_AXIS:
			tex.majorAxis = (Texture::Axes)GetU2();
			break;
		case AI_LWO_IMAG:
			tex.mClipIdx = GetU2();
			break;
		case AI_LWO_VMAP:
			GetS0(tex.mUVChannelIndex,head->length);
			break;
		case AI_LWO_WRPH:
			tex.wrapAmountH = GetF4();
			break;
		case AI_LWO_WRPW:
			tex.wrapAmountW = GetF4();
			break;
		}
		mFileBuffer = next;
	}
}

// ------------------------------------------------------------------------------------------------
void LWOImporter::LoadLWO2Procedural(unsigned int size, LWO::Texture& tex )
{
	// --- not supported at the moment
	DefaultLogger::get()->error("LWO2: Found procedural texture, this is not supported");
	tex.bCanUse = false;
}

// ------------------------------------------------------------------------------------------------
void LWOImporter::LoadLWO2Gradient(unsigned int size, LWO::Texture& tex  )
{
	// --- not supported at the moment
	DefaultLogger::get()->error("LWO2: Found gradient texture, this is not supported");
	tex.bCanUse = false;
}

// ------------------------------------------------------------------------------------------------
void LWOImporter::LoadLWO2TextureHeader(unsigned int size, LWO::Texture& tex )
{
	LE_NCONST uint8_t* const end = mFileBuffer + size;

	// get the ordinal string
	GetS0( tex.ordinal, size);

	// we could crash later if this is an empty string ...
	if (!tex.ordinal.length())
	{
		DefaultLogger::get()->error("LWO2: Ill-formed SURF.BLOK ordinal string");
		tex.ordinal = "\x00";
	}
	while (true)
	{
		if (mFileBuffer + 6 >= end)break;
		LE_NCONST IFF::SubChunkHeader* const head = IFF::LoadSubChunk(mFileBuffer);

		if (mFileBuffer + head->length > end)
			throw new ImportErrorException("LWO2: Invalid texture header chunk length");

		uint8_t* const next = mFileBuffer+head->length;
		switch (head->type)
		{
		case AI_LWO_CHAN:
			tex.type = GetU4();
			break;
		case AI_LWO_ENAB:
			tex.enabled = GetU2() ? true : false;
			break;
		case AI_LWO_OPAC:
			tex.blendType = (Texture::BlendType)GetU2();
			tex.mStrength = GetF4();
			break;
		}
		mFileBuffer = next;
	}
}

// ------------------------------------------------------------------------------------------------
void LWOImporter::LoadLWO2TextureBlock(LE_NCONST IFF::SubChunkHeader* head, unsigned int size )
{
	ai_assert(!mSurfaces->empty());
	LWO::Surface& surf = mSurfaces->back();
	LWO::Texture tex;

	// load the texture header
	LoadLWO2TextureHeader(head->length,tex);
	size -= head->length + 6;

	// now get the exact type of the texture
	switch (head->type)
	{
	case AI_LWO_PROC:
		LoadLWO2Procedural(size,tex);
		break;
	case AI_LWO_GRAD:
		LoadLWO2Gradient(size,tex); 
		break;
	case AI_LWO_IMAP:
		LoadLWO2ImageMap(size,tex);
	}

	// get the destination channel
	TextureList* listRef = NULL;
	switch (tex.type)
	{
	case AI_LWO_COLR:
		listRef = &surf.mColorTextures;break;
	case AI_LWO_DIFF:
		listRef = &surf.mDiffuseTextures;break;
	case AI_LWO_SPEC:
		listRef = &surf.mSpecularTextures;break;
	case AI_LWO_GLOS:
		listRef = &surf.mGlossinessTextures;break;
	case AI_LWO_BUMP:
		listRef = &surf.mBumpTextures;break;
	case AI_LWO_TRAN:
		listRef = &surf.mOpacityTextures;break;
	case AI_LWO_REFL:
		listRef = &surf.mReflectionTextures;break;
	default:
		DefaultLogger::get()->warn("LWO2: Encountered unknown texture type");
		return;
	}

	// now attach the texture to the parent surface - sort by ordinal string
	for (TextureList::iterator it = listRef->begin();it != listRef->end(); ++it)	{
		if (::strcmp(tex.ordinal.c_str(),(*it).ordinal.c_str()) < 0)	{
			listRef->insert(it,tex);
			return;
		}
	}
	listRef->push_back(tex);
}

// ------------------------------------------------------------------------------------------------
void LWOImporter::LoadLWO2ShaderBlock(LE_NCONST IFF::SubChunkHeader* head, unsigned int size )
{
	LE_NCONST uint8_t* const end = mFileBuffer + size;

	ai_assert(!mSurfaces->empty());
	LWO::Surface& surf = mSurfaces->back();
	LWO::Shader shader;

	// get the ordinal string
	GetS0( shader.ordinal, size);

	// we could crash later if this is an empty string ...
	if (!shader.ordinal.length())
	{
		DefaultLogger::get()->error("LWO2: Ill-formed SURF.BLOK ordinal string");
		shader.ordinal = "\x00";
	}

	// read the header
	while (true)
	{
		if (mFileBuffer + 6 >= end)break;
		LE_NCONST IFF::SubChunkHeader* const head = IFF::LoadSubChunk(mFileBuffer);

		if (mFileBuffer + head->length > end)
			throw new ImportErrorException("LWO2: Invalid shader header chunk length");

		uint8_t* const next = mFileBuffer+head->length;
		switch (head->type)
		{
		case AI_LWO_ENAB:
			shader.enabled = GetU2() ? true : false;
			break;

		case AI_LWO_FUNC:
			GetS0( shader.functionName, head->length );
		}
		mFileBuffer = next;
	}

	// now attach the shader to the parent surface - sort by ordinal string
	for (ShaderList::iterator it = surf.mShaders.begin();it != surf.mShaders.end(); ++it)	{
		if (::strcmp(shader.ordinal.c_str(),(*it).ordinal.c_str()) < 0)	{
			surf.mShaders.insert(it,shader);
			return;
		}
	}
	surf.mShaders.push_back(shader);
}

// ------------------------------------------------------------------------------------------------
void LWOImporter::LoadLWO2Surface(unsigned int size)
{
	LE_NCONST uint8_t* const end = mFileBuffer + size;

	mSurfaces->push_back( LWO::Surface () );
	LWO::Surface& surf = mSurfaces->back();

	GetS0(surf.mName,size);

	// check whether this surface was derived from any other surface
	std::string derived;
	GetS0(derived,(unsigned int)(end - mFileBuffer));
	if (derived.length())	{
		// yes, find this surface
		for (SurfaceList::iterator it = mSurfaces->begin(), end = mSurfaces->end()-1; it != end; ++it)	{
			if ((*it).mName == derived)	{
				// we have it ...
				surf = *it;
				derived.clear();break;
			}
		}
		if (derived.size())
			DefaultLogger::get()->warn("LWO2: Unable to find source surface: " + derived);
	}

	while (true)
	{
		if (mFileBuffer + 6 >= end)
			break;
		LE_NCONST IFF::SubChunkHeader* const head = IFF::LoadSubChunk(mFileBuffer);

		if (mFileBuffer + head->length > end)
			throw new ImportErrorException("LWO2: Invalid surface chunk length");

		uint8_t* const next = mFileBuffer+head->length;
		switch (head->type)
		{
			// diffuse color
		case AI_LWO_COLR:
			{
				AI_LWO_VALIDATE_CHUNK_LENGTH(head->length,COLR,12);
				surf.mColor.r = GetF4();
				surf.mColor.g = GetF4();
				surf.mColor.b = GetF4();
				break;
			}
			// diffuse strength ... hopefully
		case AI_LWO_DIFF:
			{
				AI_LWO_VALIDATE_CHUNK_LENGTH(head->length,DIFF,4);
				surf.mDiffuseValue = GetF4();
				break;
			}
			// specular strength ... hopefully
		case AI_LWO_SPEC:
			{
				AI_LWO_VALIDATE_CHUNK_LENGTH(head->length,SPEC,4);
				surf.mSpecularValue = GetF4();
				break;
			}
			// transparency
		case AI_LWO_TRAN:
			{
				// transparency explicitly disabled?
				if (surf.mTransparency == 10e10f)
					break;

				AI_LWO_VALIDATE_CHUNK_LENGTH(head->length,TRAN,4);
				surf.mTransparency = GetF4();
				break;
			}
			// additive transparency
		case AI_LWO_ADTR:
			{
				AI_LWO_VALIDATE_CHUNK_LENGTH(head->length,ADTR,4);
				surf.mAdditiveTransparency = GetF4();
				break;
			}
			// wireframe mode
		case AI_LWO_LINE:
			{
				AI_LWO_VALIDATE_CHUNK_LENGTH(head->length,LINE,2);
				if (GetU2() & 0x1)
					surf.mWireframe = true;
				break;
			}
			// glossiness
		case AI_LWO_GLOS:
			{
				AI_LWO_VALIDATE_CHUNK_LENGTH(head->length,GLOS,4);
				surf.mGlossiness = GetF4();
				break;
			}
			// bump intensity
		case AI_LWO_BUMP:
			{
				AI_LWO_VALIDATE_CHUNK_LENGTH(head->length,BUMP,4);
				surf.mBumpIntensity = GetF4();
				break;
			}
			// color highlights
		case AI_LWO_CLRH:
			{
				AI_LWO_VALIDATE_CHUNK_LENGTH(head->length,CLRH,4);
				surf.mColorHighlights = GetF4();
				break;
			}
			// index of refraction
		case AI_LWO_RIND:
			{
				AI_LWO_VALIDATE_CHUNK_LENGTH(head->length,RIND,4);
				surf.mIOR = GetF4();
				break;
			}
			// polygon sidedness
		case AI_LWO_SIDE:
			{
				AI_LWO_VALIDATE_CHUNK_LENGTH(head->length,SIDE,2);
				surf.bDoubleSided = (3 == GetU2());
				break;
			}
			// maximum smoothing angle
		case AI_LWO_SMAN:
			{
				AI_LWO_VALIDATE_CHUNK_LENGTH(head->length,SMAN,4);
				surf.mMaximumSmoothAngle = fabs( GetF4() );
				break;
			}
			// vertex color channel to be applied to the surface
		case AI_LWO_VCOL:
			{
				AI_LWO_VALIDATE_CHUNK_LENGTH(head->length,VCOL,12);
				surf.mDiffuseValue *= GetF4();				// strength
				ReadVSizedIntLWO2(mFileBuffer);             // skip envelope
				surf.mVCMapType = GetU4();					// type of the channel

				// name of the channel
				GetS0(surf.mVCMap, (unsigned int) (next - mFileBuffer ));
				break;
			}
			// surface bock entry
		case AI_LWO_BLOK:
			{
				AI_LWO_VALIDATE_CHUNK_LENGTH(head->length,BLOK,4);
				LE_NCONST IFF::SubChunkHeader* head2 = IFF::LoadSubChunk(mFileBuffer);

				switch (head2->type)
				{
				case AI_LWO_PROC:
				case AI_LWO_GRAD:
				case AI_LWO_IMAP:
					LoadLWO2TextureBlock(head2, head->length);
					break;
				case AI_LWO_SHDR:
					LoadLWO2ShaderBlock(head2, head->length);
					break;

				default:
					DefaultLogger::get()->warn("LWO2: Found an unsupported surface BLOK");
				};

				break;
			}
		}
		mFileBuffer = next;
	}
}

#endif // !! ASSIMP_BUILD_NO_X_IMPORTER