// 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 __I_SKINNED_MESH_H_INCLUDED__
#define __I_SKINNED_MESH_H_INCLUDED__

#include "irrArray.h"
#include "IBoneSceneNode.h"
#include "IAnimatedMesh.h"
#include "SSkinMeshBuffer.h"

namespace irr
{
namespace scene
{

	enum E_INTERPOLATION_MODE
	{
		// constant does use the current key-values without interpolation
		EIM_CONSTANT = 0,

		// linear interpolation
		EIM_LINEAR,

		//! count of all available interpolation modes
		EIM_COUNT
	};


	//! Interface for using some special functions of Skinned meshes
	class ISkinnedMesh : public IAnimatedMesh
	{
	public:

		//! Gets joint count.
		/** \return Amount of joints in the skeletal animated mesh. */
		virtual u32 getJointCount() const = 0;

		//! Gets the name of a joint.
		/** \param number: Zero based index of joint. The last joint
		has the number getJointCount()-1;
		\return Name of joint and null if an error happened. */
		virtual const c8* getJointName(u32 number) const = 0;

		//! Gets a joint number from its name
		/** \param name: Name of the joint.
		\return Number of the joint or -1 if not found. */
		virtual s32 getJointNumber(const c8* name) const = 0;

		//! Use animation from another mesh
		/** The animation is linked (not copied) based on joint names
		so make sure they are unique.
		\return True if all joints in this mesh were
		matched up (empty names will not be matched, and it's case
		sensitive). Unmatched joints will not be animated. */
		virtual bool useAnimationFrom(const ISkinnedMesh *mesh) = 0;

		//! Update Normals when Animating
		/** \param on If false don't animate, which is faster.
		Else update normals, which allows for proper lighting of
		animated meshes. */
		virtual void updateNormalsWhenAnimating(bool on) = 0;

		//! Sets Interpolation Mode
		virtual void setInterpolationMode(E_INTERPOLATION_MODE mode) = 0;

		//! Animates this mesh's joints based on frame input
		virtual void animateMesh(f32 frame, f32 blend)=0;

		//! Preforms a software skin on this mesh based of joint positions
		virtual void skinMesh() = 0;

		//! converts the vertex type of all meshbuffers to tangents.
		/** E.g. used for bump mapping. */
		virtual void convertMeshToTangents() = 0;

		//! Allows to enable hardware skinning.
		/* This feature is not implemented in Irrlicht yet */
		virtual bool setHardwareSkinning(bool on) = 0;

		//! Refreshes vertex data cached in joints such as positions and normals
		virtual void refreshJointCache() = 0;

		//! Moves the mesh into static position.
		virtual void resetAnimation() = 0;

		//! A vertex weight
		struct SWeight
		{
			//! Index of the mesh buffer
			u16 buffer_id; //I doubt 32bits is needed

			//! Index of the vertex
			u32 vertex_id; //Store global ID here

			//! Weight Strength/Percentage (0-1)
			f32 strength;

		private:
			//! Internal members used by CSkinnedMesh
			friend class CSkinnedMesh;
			char *Moved;
			core::vector3df StaticPos;
			core::vector3df StaticNormal;
		};


		//! Animation keyframe which describes a new position
		struct SPositionKey
		{
			f32 frame;
			core::vector3df position;
		};

		//! Animation keyframe which describes a new scale
		struct SScaleKey
		{
			f32 frame;
			core::vector3df scale;
		};

		//! Animation keyframe which describes a new rotation
		struct SRotationKey
		{
			f32 frame;
			core::quaternion rotation;
		};

		//! Joints
		struct SJoint
		{
			SJoint() : UseAnimationFrom(0), GlobalSkinningSpace(false),
				positionHint(-1),scaleHint(-1),rotationHint(-1)
			{
			}

			//! The name of this joint
			core::stringc Name;

			//! Local matrix of this joint
			core::matrix4 LocalMatrix;

			//! List of child joints
			core::array<SJoint*> Children;

			//! List of attached meshes
			core::array<u32> AttachedMeshes;

			//! Animation keys causing translation change
			core::array<SPositionKey> PositionKeys;

			//! Animation keys causing scale change
			core::array<SScaleKey> ScaleKeys;

			//! Animation keys causing rotation change
			core::array<SRotationKey> RotationKeys;

			//! Skin weights
			core::array<SWeight> Weights;

			//! Unnecessary for loaders, will be overwritten on finalize
			core::matrix4 GlobalMatrix;
			core::matrix4 GlobalAnimatedMatrix;
			core::matrix4 LocalAnimatedMatrix;
			core::vector3df Animatedposition;
			core::vector3df Animatedscale;
			core::quaternion Animatedrotation;

			core::matrix4 GlobalInversedMatrix; //the x format pre-calculates this

		private:
			//! Internal members used by CSkinnedMesh
			friend class CSkinnedMesh;

			SJoint *UseAnimationFrom;
			bool GlobalSkinningSpace;

			s32 positionHint;
			s32 scaleHint;
			s32 rotationHint;
		};


		//Interface for the mesh loaders (finalize should lock these functions, and they should have some prefix like loader_

		//these functions will use the needed arrays, set values, etc to help the loaders

		//! exposed for loaders: to add mesh buffers
		virtual core::array<SSkinMeshBuffer*>& getMeshBuffers() = 0;

		//! exposed for loaders: joints list
		virtual core::array<SJoint*>& getAllJoints() = 0;

		//! exposed for loaders: joints list
		virtual const core::array<SJoint*>& getAllJoints() const = 0;

		//! loaders should call this after populating the mesh
		virtual void finalize() = 0;

		//! Adds a new meshbuffer to the mesh, access it as last one
		virtual SSkinMeshBuffer* addMeshBuffer() = 0;

		//! Adds a new joint to the mesh, access it as last one
		virtual SJoint* addJoint(SJoint *parent=0) = 0;

		//! Adds a new weight to the mesh, access it as last one
		virtual SWeight* addWeight(SJoint *joint) = 0;

		//! Adds a new position key to the mesh, access it as last one
		virtual SPositionKey* addPositionKey(SJoint *joint) = 0;
		//! Adds a new scale key to the mesh, access it as last one
		virtual SScaleKey* addScaleKey(SJoint *joint) = 0;
		//! Adds a new rotation key to the mesh, access it as last one
		virtual SRotationKey* addRotationKey(SJoint *joint) = 0;

		//! Check if the mesh is non-animated
		virtual bool isStatic()=0;
	};

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

#endif

