/**
 * =========================================================================
 * File        : SkeletonAnim.h
 * Project     : 0 A.D.
 * Description : Raw description of a skeleton animation
 * =========================================================================
 */

#ifndef INCLUDED_SKELETONANIMDEF
#define INCLUDED_SKELETONANIMDEF

#include "maths/Vector3D.h"
#include "maths/Quaternion.h"

////////////////////////////////////////////////////////////////////////////////////////
// CBoneState: structure describing state of a bone at some point
class CBoneState 
{
public:
    // translation of bone relative to root
    CVector3D m_Translation;
    // rotation of bone relative to root
    CQuaternion m_Rotation;
};


////////////////////////////////////////////////////////////////////////////////////////
// CSkeletonAnimDef: raw description - eg bonestates - of an animation that plays upon 
// a skeleton
class CSkeletonAnimDef
{
public:
    // current file version given to saved animations
    enum { FILE_VERSION = 1 };
    // supported file read version - files with a version less than this will be rejected
    enum { FILE_READ_VERSION = 1 };


public:
    // Key: description of a single key in a skeleton animation
    typedef CBoneState Key;

public:
    // CSkeletonAnimDef constructor + destructor
    CSkeletonAnimDef();
    ~CSkeletonAnimDef();

    // return the number of keys in this animation
    size_t GetNumKeys() const { return (size_t)m_NumKeys; }

    // accessors: get a key for given bone at given time
    Key& GetKey(u32 frame, u32 bone) { return m_Keys[frame*m_NumKeys+bone]; }
    const Key& GetKey(u32 frame, u32 bone) const { return m_Keys[frame*m_NumKeys+bone]; }   

    // get duration of this anim, in ms
    float GetDuration() const { return m_NumFrames*m_FrameTime; }

    // return length of each frame, in ms
    float GetFrameTime() const { return m_FrameTime; }
    // return number of frames in animation
    size_t GetNumFrames() const { return (size_t)m_NumFrames; }

    // build matrices for all bones at the given time (in MS) in this animation
    void BuildBoneMatrices(float time, CMatrix3D* matrices, bool loop) const;

    // anim I/O functions
    static CSkeletonAnimDef* Load(const char* filename);
    static void Save(const char* filename, const CSkeletonAnimDef* anim);

public:
    // frame time - time between successive frames, in ms
    float m_FrameTime;
    // number of keys in each frame - should match number of bones in the skeleton
    u32 m_NumKeys;
    // number of frames in the animation
    u32 m_NumFrames;
    // animation data - m_NumKeys*m_NumFrames total keys
    Key* m_Keys;
};

#endif