// Copyright (C) 2002-2012 Nikolaus Gebhardt
// This file is part of the "Irrlicht Engine".
// For conditions of distribution and use, see copyright notice in irrlicht.h

#ifndef IRR_I_MESH_LOADER_H_INCLUDED
#define IRR_I_MESH_LOADER_H_INCLUDED

#include "IReferenceCounted.h"
#include "path.h"
#include "IMeshTextureLoader.h"
#include "SVertexIndex.h"

namespace irr
{
namespace io
{
	class IReadFile;
} // end namespace io
namespace scene
{
	class IAnimatedMesh;

//! Class which is able to load an animated mesh from a file.
/** If you want Irrlicht be able to load meshes of
currently unsupported file formats (e.g. .cob), then implement
this and add your new Meshloader with
ISceneManager::addExternalMeshLoader() to the engine. */
class IMeshLoader : public virtual IReferenceCounted
{
public:

	//! Constructor
	IMeshLoader() : TextureLoader(0), IndexTypeHint(EITH_16BIT)	{}

	//! Destructor
	virtual ~IMeshLoader()
	{
		if ( TextureLoader )
			TextureLoader->drop();
	}

	//! Returns true if the file might be loaded by this class.
	/** This decision should be based on the file extension (e.g. ".cob")
	only.
	\param filename Name of the file to test.
	\return True if the file might be loaded by this class. */
	virtual bool isALoadableFileExtension(const io::path& filename) const = 0;

	//! Creates/loads an animated mesh from the file.
	/** \param file File handler to load the file from.
	\return Pointer to the created mesh. Returns 0 if loading failed.
	If you no longer need the mesh, you should call IAnimatedMesh::drop().
	See IReferenceCounted::drop() for more information. */
	virtual IAnimatedMesh* createMesh(io::IReadFile* file) = 0;

	//! Set a new texture loader which this meshloader can use when searching for textures.
	/** NOTE: Not all meshloaders do support this interface. Meshloaders which
	support it will return a non-null value in getMeshTextureLoader from the start. Setting a
	texture-loader to a meshloader which doesn't support it won't help.
	\param textureLoader The textureloader to use. When set to NULL the mesh will not load any textures.
	*/
	virtual void setMeshTextureLoader(IMeshTextureLoader* textureLoader)
	{
		if ( textureLoader != TextureLoader )
		{
			if ( textureLoader )
				textureLoader->grab();
			if ( TextureLoader )
				TextureLoader->drop();
			TextureLoader = textureLoader;
		}
	}

	//! Get the texture loader used when this meshloader searches for textures.
	/** NOTE: not all meshloaders support this interface so this can return NULL.
	*/
	virtual IMeshTextureLoader* getMeshTextureLoader() const
	{
		return TextureLoader;
	}

	enum E_INDEX_TYPE_HINT
	{
		//! Prefer to use 16-bit index buffers even if it breaks the mesh
		EITH_16BIT,

		//! Allow using 32-bit index buffers
		EITH_32BIT,

		//! Allow 32-bit, but copy back to 16-bit when 32 is not needed.
		//! So tiny overhead on loading, but meshes are later more optimal
		EITH_OPTIMAL
	};


	//! Give loader a hint if you would prefer 16 or 32 bit meshbuffers.
	/** 
	Generally Irrlicht works with 16-bit meshbuffers so far.
	Rendering 32-bit meshbuffers works, other functions like 
	mesh-writing and mesh manipulation might not work yet.
	NOTE: Most loaders will ignore this hint so far, but hopefully 
	will care about it in the future.
	*/
	void setIndexTypeHint(E_INDEX_TYPE_HINT typeHint)
	{
		IndexTypeHint = typeHint;
	}

	//! Return current preference user has for the index type of meshbuffers
	/** Note that this is _not_ necessarily the type used by the meshloader */
	E_INDEX_TYPE_HINT getIndexTypeHint() const
	{
		return IndexTypeHint;
	}


protected:
	IMeshTextureLoader* TextureLoader;
	E_INDEX_TYPE_HINT IndexTypeHint;
};


} // end namespace scene
} // end namespace irr

#endif