// Copyright (C) 2002-2011 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_COLLADA_MESH_WRITER_H_INCLUDED__
#define __IRR_I_COLLADA_MESH_WRITER_H_INCLUDED__

#include "IMeshWriter.h"
#include "ISceneNode.h"
#include "IAnimatedMesh.h"
#include "SMaterial.h"

namespace irr
{
namespace io
{
	class IWriteFile;
} // end namespace io

namespace scene
{
	//! Lighting models - more or less the way Collada categorizes materials
	enum E_COLLADA_TECHNIQUE_FX
	{
		//! Blinn-phong which is default for opengl and dx fixed function pipelines.
		//! But several well-known renderers don't support it and prefer phong.
		ECTF_BLINN,	
		//! Phong shading, default in many external renderers.
		ECTF_PHONG,
		//! diffuse shaded surface that is independent of lighting.
		ECTF_LAMBERT,
		// constantly shaded surface that is independent of lighting. 
		ECTF_CONSTANT
	};

	//! How to interpret the opacity in collada
	enum E_COLLADA_TRANSPARENT_FX
	{
		//! default - only alpha channel of color or texture is used.
		ECOF_A_ONE = 0,

		//! Alpha values for each RGB channel of color or texture are used. 
		ECOF_RGB_ZERO = 1
	};

	//! Color names collada uses in it's color samplers
	enum E_COLLADA_COLOR_SAMPLER
	{
		ECCS_DIFFUSE,
		ECCS_AMBIENT,
		ECCS_EMISSIVE,
		ECCS_SPECULAR,
		ECCS_TRANSPARENT,
		ECCS_REFLECTIVE
	};

	//! Irrlicht colors which can be mapped to E_COLLADA_COLOR_SAMPLER values
	enum E_COLLADA_IRR_COLOR
	{
		//! Don't write this element at all
		ECIC_NONE,

		//! Check IColladaMeshWriterProperties for custom color
		ECIC_CUSTOM,

		//! Use SMaterial::DiffuseColor
		ECIC_DIFFUSE,

		//! Use SMaterial::AmbientColor
		ECIC_AMBIENT,

		//! Use SMaterial::EmissiveColor
		ECIC_EMISSIVE,

		//! Use SMaterial::SpecularColor
		ECIC_SPECULAR
	};

	//! Callback interface for properties which can be used to influence collada writing
	//! NOTE: Interface is still work in process and might change some more before 1.8 release
	class IColladaMeshWriterProperties  : public virtual IReferenceCounted
	{
	public:
		virtual ~IColladaMeshWriterProperties ()	{}

		//! Which lighting model should be used in the technique (FX) section when exporting effects (materials)
		virtual E_COLLADA_TECHNIQUE_FX getTechniqueFx(const video::SMaterial& material) const = 0;

		//! Which texture index should be used when writing the texture of the given sampler color.
		/** \return the index to the texture-layer or -1 if that texture should never be exported 
			Note: for ECCS_TRANSPARENT by default the alpha channel is used, if you want to use RGB you have to set
			also the ECOF_RGB_ZERO flag in getTransparentFx.  */
		virtual s32 getTextureIdx(const video::SMaterial & material, E_COLLADA_COLOR_SAMPLER cs) const = 0;

		//! Return which color from Irrlicht should be used for the color requested by collada
		/** Note that collada allows exporting either texture or color, not both. 
			So color mapping is only checked if we have no valid texture already.
			By default we try to return best fits when possible. For example ECCS_DIFFUSE is mapped to ECIC_DIFFUSE.
			When ECIC_CUSTOM is returned then the result of getCustomColor will be used. */
		virtual E_COLLADA_IRR_COLOR getColorMapping(const video::SMaterial & material, E_COLLADA_COLOR_SAMPLER cs) const = 0;

		//! Return custom colors for certain color types requested by collada. 
		/** Only used when getColorMapping returns ECIC_CUSTOM for the same paramters. */
		virtual video::SColor getCustomColor(const video::SMaterial & material, E_COLLADA_COLOR_SAMPLER cs) const = 0;

		//! Return the transparence color interpretation.
		/** Not this is only about ECCS_TRANSPARENT and does not affect getTransparency. */
		virtual E_COLLADA_TRANSPARENT_FX getTransparentFx(const video::SMaterial& material) const = 0;

		//! Transparency value for that material. 
		/** This value is additional to transparent settings, if both are set they will be multiplicated.
		\return 1.0 for fully transparent, 0.0 for not transparent and not written at all when < 0.f */
		virtual f32 getTransparency(const video::SMaterial& material) const = 0;

		//! Reflectivity value for that material
		/** The amount of perfect mirror reflection to be added to the reflected light 
		\return 0.0 - 1.0 for reflectivity and element is not written at all when < 0.f */
		virtual f32 getReflectivity(const video::SMaterial& material) const = 0;

		//! Return index of refraction for that material
		/**	By default we don't write that.
		\return a value >= 0.f to write <index_of_refraction> when it's < 0 nothing will be written */
		virtual f32 getIndexOfRefraction(const video::SMaterial& material) const = 0;

		//! Should node be used in scene export? (only needed for scene-writing, ignored in mesh-writing)
		//! By default all visible nodes are exported.
		virtual bool isExportable(const irr::scene::ISceneNode * node) const = 0;

		//! Return the mesh for the given node. If it has no mesh or shouldn't export it's mesh 
		//! you can return 0 in which case only the transformation matrix of the node will be used.
		virtual IMesh* getMesh(irr::scene::ISceneNode * node) = 0;
	};


	//! Interface for writing meshes
	class IColladaMeshWriter : public IMeshWriter
	{
	public:

		IColladaMeshWriter() : Properties(0), DefaultProperties(0), WriteTextures(true), WriteDefaultScene(false), AmbientLight(0.f, 0.f, 0.f, 1.f)
		{
		}

		//! Destructor
		virtual ~IColladaMeshWriter() 
		{
			if ( Properties )
				Properties->drop();
			if ( DefaultProperties )
				DefaultProperties->drop();
		}

		//! writes a scene starting with the given node
		virtual bool writeScene(io::IWriteFile* file, scene::ISceneNode* root) = 0;


		//! Set if texture information should be written
		virtual void setWriteTextures(bool write)
		{
			WriteTextures = write;
		}

		//! Get if texture information should be written
		virtual bool getWriteTextures() const 
		{
			return WriteTextures;
		}

		//! Set if a default scene should be written when writing meshes.
		/** Many collada readers fail to read a mesh if the collada files doesn't contain a scene as well.
		The scene is doing an instantiation of the mesh.
		When using writeScene this flag is ignored (as we have scene there already)
		*/
		virtual void setWriteDefaultScene(bool write)
		{
			WriteDefaultScene = write;
		}

		//! Get if a default scene should be written
		virtual bool getWriteDefaultScene() const
		{
			return WriteDefaultScene;
		}

		//! Sets ambient color of the scene to write
		virtual void setAmbientLight(const video::SColorf &ambientColor)
		{
			AmbientLight = ambientColor;
		}

		//! Return ambient light of the scene which is written
		virtual video::SColorf getAmbientLight() const
		{
			return AmbientLight;
		}

		//! Set properties to use by the meshwriter instead of it's default properties.
		/** Overloading properties with an own class allows modifying the writing process in certain ways. 
		By default properties are set to the DefaultProperties. */
		virtual void setProperties(IColladaMeshWriterProperties * p)
		{
			if ( p == Properties )
				return;
			if ( p ) 
				p->grab();
			if ( Properties )
				Properties->drop();
			Properties = p;
		}

		//! Get properties which are currently used.
		virtual IColladaMeshWriterProperties * getProperties()
		{
			return Properties;
		}

		//! Return the original default properties of the writer. 
		/** You can use this pointer in your own properties to access and return default values. */
		IColladaMeshWriterProperties * getDefaultProperties() const 
		{ 
			return DefaultProperties; 
		}

	protected:
		// NOTE: you should also call setProperties
		virtual void setDefaultProperties(IColladaMeshWriterProperties * p)
		{
			if ( p == DefaultProperties )
				return;
			if ( p ) 
				p->grab();
			if ( DefaultProperties )
				DefaultProperties->drop();
			DefaultProperties = p;
		}

	private:
		IColladaMeshWriterProperties * Properties;
		IColladaMeshWriterProperties * DefaultProperties;
		bool WriteTextures;
		bool WriteDefaultScene;
		video::SColorf AmbientLight;
	};


} // end namespace
} // end namespace

#endif
