//---------------------------------------------------------------
// Helper class to store GPU related resources created for
// a given aiMesh
//---------------------------------------------------------------
class MeshHelper
{
	public:

		MeshHelper ()
			: 
			piVB				(NULL),
			piIB				(NULL),
			piEffect			(NULL),
			piVBNormals			(NULL),
			piDiffuseTexture	(NULL),
			piSpecularTexture	(NULL),
			piAmbientTexture	(NULL),
			piNormalTexture		(NULL),
			piEmissiveTexture	(NULL),
			piOpacityTexture	(NULL),
			piShininessTexture	(NULL),
			piLightmapTexture	(NULL),
			//pvOriginalNormals	(NULL),
			bSharedFX(false),
			twosided (false){}

		~MeshHelper ()
		{
			// NOTE: This is done in DeleteAssetData()
			// TODO: Make this a proper d'tor
		}

		// shading mode to use. Either Lambert or otherwise phong
		// will be used in every case
		//aiShadingMode eShadingMode;

		// vertex buffer
		IDirect3DVertexBuffer9* piVB;

		// index buffer. For partially transparent meshes
		// created with dynamic usage to be able to update
		// the buffer contents quickly
		IDirect3DIndexBuffer9* piIB;

		// vertex buffer to be used to draw vertex normals
		// (vertex normals are generated in every case)
		IDirect3DVertexBuffer9* piVBNormals;

		// shader to be used
		ID3DXEffect* piEffect;
		bool bSharedFX;

		// material textures
		IDirect3DTexture9* piDiffuseTexture;
		IDirect3DTexture9* piSpecularTexture;
		IDirect3DTexture9* piAmbientTexture;
		IDirect3DTexture9* piEmissiveTexture;
		IDirect3DTexture9* piNormalTexture;
		IDirect3DTexture9* piOpacityTexture;
		IDirect3DTexture9* piShininessTexture;
		IDirect3DTexture9* piLightmapTexture;

		// material colors
		D3DXVECTOR4 vDiffuseColor;
		D3DXVECTOR4 vSpecularColor;
		D3DXVECTOR4 vAmbientColor;
		D3DXVECTOR4 vEmissiveColor;

		// opacity for the material
		float fOpacity;

		// shininess for the material
		float fShininess;

		// strength of the specular highlight
		float fSpecularStrength;

		// two-sided?
		bool twosided;

		// Stores a pointer to the original normal set of the asset
		//aiVector3D* pvOriginalNormals;
};

////////////////////////////////////////////////////////////
// default vertex data structure
// (even if tangents, bitangents or normals aren't
// required by the shader they will be committed to the GPU)
////////////////////////////////////////////////////////////
struct Vertex
{
	aiVector3D vPosition;
	aiVector3D vNormal;

	D3DCOLOR dColorDiffuse;
	aiVector3D vTangent;
	aiVector3D vBitangent;
	aiVector2D vTextureUV;
	aiVector2D vTextureUV2;
	unsigned char mBoneIndices[4];
	unsigned char mBoneWeights[4]; // last Weight not used, calculated inside the vertex shader

	/** Returns the vertex declaration elements to create a declaration from. */
	static D3DVERTEXELEMENT9* GetDeclarationElements() 
	{
		static D3DVERTEXELEMENT9 decl[] =
		{
			{ 0,  0, D3DDECLTYPE_FLOAT3,   D3DDECLMETHOD_DEFAULT, D3DDECLUSAGE_POSITION,	 0 },
			{ 0, 12, D3DDECLTYPE_FLOAT3,   D3DDECLMETHOD_DEFAULT, D3DDECLUSAGE_NORMAL,		 0 },
			{ 0, 24, D3DDECLTYPE_D3DCOLOR, D3DDECLMETHOD_DEFAULT, D3DDECLUSAGE_COLOR,		 0 },
			{ 0, 28, D3DDECLTYPE_FLOAT3,   D3DDECLMETHOD_DEFAULT, D3DDECLUSAGE_TANGENT,		 0 },
			{ 0, 40, D3DDECLTYPE_FLOAT3,   D3DDECLMETHOD_DEFAULT, D3DDECLUSAGE_BINORMAL,	 0 },
			{ 0, 52, D3DDECLTYPE_FLOAT2,   D3DDECLMETHOD_DEFAULT, D3DDECLUSAGE_TEXCOORD,	 0 },
			{ 0, 60, D3DDECLTYPE_FLOAT2,   D3DDECLMETHOD_DEFAULT, D3DDECLUSAGE_TEXCOORD,	 1 },
			{ 0, 68, D3DDECLTYPE_UBYTE4,   D3DDECLMETHOD_DEFAULT, D3DDECLUSAGE_BLENDINDICES, 0 },
			{ 0, 72, D3DDECLTYPE_UBYTE4N,  D3DDECLMETHOD_DEFAULT, D3DDECLUSAGE_BLENDWEIGHT,  0 },
			D3DDECL_END()
		};

		return decl;
	}
};

////////////////////////////////////////////////////////////
// FVF vertex structure used for normals
////////////////////////////////////////////////////////////
struct LineVertex
{
	aiVector3D vPosition;
	DWORD dColorDiffuse;

	// retrieves the FVF code of the vertex type
	static DWORD GetFVF()
	{
		return D3DFVF_DIFFUSE | D3DFVF_XYZ;
	}
};