/*
	Copyright (C) 2005-2006 Feeling Software Inc.
	MIT License: http://www.opensource.org/licenses/mit-license.php
*/
/*
	Based on the FS Import classes:
	Copyright (C) 2005-2006 Feeling Software Inc
	Copyright (C) 2005-2006 Autodesk Media Entertainment
	MIT License: http://www.opensource.org/licenses/mit-license.php
*/

/**
	@file FCDSkinController.h
	This file contains the FCDSkinController class.
*/

#ifndef _FCD_SKIN_CONTROLLER_H_
#define _FCD_SKIN_CONTROLLER_H_

#include "FCDocument/FCDObject.h"

class FCDocument;
class FCDController;
class FCDGeometry;
class FCDSceneNode;

/**
	A weighted joint index used in skinning.
*/
struct FCDJointWeightPair
{
	/** Default constructor: sets both the joint index and the weight to zero. */
	FCDJointWeightPair() { jointIndex = 0; weight = 0.0f; }

	/** Constructor: sets the joint index and the weight to the given values.
		@param _jointIndex The jointIndex.
		@param _weight Its weight. */
	FCDJointWeightPair(uint32 _jointIndex, float _weight) { jointIndex = _jointIndex; weight = _weight; }

	uint32 jointIndex; /**< A joint index. Use this index within the skin's joint list. */
	float weight; /**< A skinning weight. */
};

/**
	A joint and its bind pose used in skinning.
*/
struct FCDJointMatrixPair
{
	FMMatrix44 invertedBindPose; /**< The inverse matrix of the bind pose of the joint. */
	FCDSceneNode* joint; /**< A joint. */
};

/** A dynamically-sized array of joints and bind poses. */
typedef vector<FCDJointMatrixPair> FCDJointList;

/** A dynamically-sized array of weighted joint indices.
	The sum of the weights within this list should always add up to one. */
typedef vector<FCDJointWeightPair> FCDJointWeightPairList;

/** A dynamically-sized array of weighted joint index lists.
	Each entry within this list represents one vertex of the skinned geometry. */
typedef vector<FCDJointWeightPairList> FCDWeightedMatches;

/**
	A COLLADA skin controller.

	The skin controller holds the information to skin a geometric object.
	That information includes a target/base entity and its bind-pose matrix,
	a list of joints and their bind pose and the influences for the joints.

	The influences are a list, for each vertex of the target entity, of which
	joints affect the vertex and by how much.

	@ingroup FCDGeometry
*/
class FCOLLADA_EXPORT FCDSkinController : public FCDObject
{
private:
	DeclareObjectType;
	FCDController* parent;

	bool ownsTarget;
	FCDEntity* target;
	FMMatrix44 bindShapeTransform;

	StringList jointIds;
	FCDJointList joints;
	FCDWeightedMatches weightedMatches;

public:
	/** Constructor: do not use directly.
		Instead, use the FCDController::CreateSkinController function.
		@param document The COLLADA document that owns the skin.
		@param parent The COLLADA controller that contains this skin. */
	FCDSkinController(FCDocument* document, FCDController* parent);

	/** Destructor: do not use directly.
		Instead, release the parent controller or create a new skin/morpher. */
	virtual ~FCDSkinController();
	
	/** Retrieves the target entity.
		This entity may be a geometric entity or another controller.
		@return The target entity. */
	FCDEntity* GetTarget() { return target; }
	const FCDEntity* GetTarget() const { return target; } /**< See above. */

	/** Sets the target entity.
		This function has very important ramifications, as the number
		of vertices may change. The influences list will be modified to
		follow the number of vertices.
		This entity may be a geometric entity or another controller.
		@param _target The target entity. */
	void SetTarget(FCDEntity* _target);

	/** Retrieves the bind-pose transform of the target entity.
		@return The bind-pose transform. */
	const FMMatrix44& GetBindShapeTransform() const { return bindShapeTransform; }

	/** Sets the bind-pose transform of the target entity.
		@param bindPose The bind-pose transform. */
	void SetBindShapeTransform(const FMMatrix44& bindPose) { bindShapeTransform = bindPose; }

	/** Retrieves a list of the joints that influence this skin.
		@return The list of joints. */
	FCDJointList& GetJoints() { return joints; }
	const FCDJointList& GetJoints() const { return joints; } /**< See above. */

	/** Retrieves the number of joints that influence the skin.
		@return The number of joints. */
	size_t GetJointCount() const { return joints.size(); }

	/** Retrieves a specific joint.
		@param index The index of the joint.
		@return The joint. This pointer will be NULL, if the index is out-of-bounds. */
	FCDJointMatrixPair* GetJoint(size_t index) { FUAssert(index < GetJointCount(), return NULL); return &joints.at(index); }
	const FCDJointMatrixPair* GetJoint(size_t index) const { FUAssert(index < GetJointCount(), return NULL); return &joints.at(index); } /**< See above. */

	/** Retrieves the information specific to a given joint.
		@param joint The joint.
		@return The information specific to this joint. This pointer will be NULL
			if the given joint does not influence this skin. */
	FCDJointMatrixPair* FindJoint(FCDSceneNode* joint);
	const FCDJointMatrixPair* FindJoint(const FCDSceneNode* joint) const; /**< See above. */

	/** Adds a joint and its bind-pose to the list of joint influencing the skin.
		@param joint The joint.
		@param bindPose The joint's bind-pose. This matrix will be inverted by this function. */
	void AddJoint(FCDSceneNode* joint, const FMMatrix44& bindPose);

	/** Removes a joint from the list of joints influencing the skin.
		All the per-vertex influences that use this joint will be removed.
		@param joint The joint. */
	void RemoveJoint(FCDSceneNode* joint);

	/** Retrieves a list of the per-vertex influences for the skin.
		You should not modify the size of the list. Instead, use the SetTarget function.
		@deprecated Will be replaces by GetVertexInfluences.
		@return The list of per-vertex influences. */
	FCDWeightedMatches& GetWeightedMatches() { return weightedMatches; }
	const FCDWeightedMatches& GetWeightedMatches() const { return weightedMatches; } /**< See above. */

	/** Retrieves a list of the per-vertex influences for the skin.
		You should not modify the size of the list. Instead, use the SetTarget function.
		@return The list of per-vertex influences. */
	FCDWeightedMatches& GetVertexInfluences() { return weightedMatches; }
	const FCDWeightedMatches& GetVertexInfluences() const { return weightedMatches; } /**< See above. */

	/** Retrieves the number of per-vertex influences.
		This value should be equal to the number of vertices/control points
		within the target geometric entity.
		@return The number of per-vertex influences. */
	size_t GetVertexInfluenceCount() const { return weightedMatches.size(); }

	/** Retrieves the per-vertex influences for a given vertex. 
		@param index The vertex index.
		@return The per-vertex influences. */
	FCDJointWeightPairList* GetInfluences(size_t index) { FUAssert(index < GetVertexInfluenceCount(), return NULL); return &weightedMatches.at(index); }
	const FCDJointWeightPairList* GetInfluences(size_t index) const { FUAssert(index < GetVertexInfluenceCount(), return NULL); return &weightedMatches.at(index); } /**< See above. */

	/** Reduces the number of joints influencing each vertex.
		1) All the influences with a weight less than the minimum will be removed.
		2) If a vertex has more influences than the given maximum, they will be sorted and the
			most important influences will be kept.
		If some of the influences for a vertex are removed, the weight will be normalized.
		@param maxInfluenceCount The maximum number of influence to keep for each vertex.
		@param minimumWeight The smallest weight to keep. */
	void ReduceInfluences(uint32 maxInfluenceCount, float minimumWeight=0.0f);

	/** [INTERNAL] Reads in the \<skin\> element from a given COLLADA XML tree node.
		@param skinNode The COLLADA XML tree node.
		@return The status of the import. If the status is not successful,
			it may be dangerous to extract information from the skin.*/
	FUStatus LoadFromXML(xmlNode* skinNode);

	/** [INTERNAL] Writes out the \<skin\> element to the given COLLADA XML tree node.
		@param parentNode The COLLADA XML parent node in which to insert the skin information.
		@return The created element XML tree node. */
	xmlNode* WriteToXML(xmlNode* parentNode) const;

	/** [INTERNAL] Links the skin with its joints.
		Since the scene graph is imported after the controllers, this function is used
		to link the skin with its joints.
		@return The status of the linkage.*/
	FUStatus Link();
};

#endif // _FCD_SKIN_CONTROLLER_H_