axmol/core/physics/CCPhysicsJoint.h

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 Copyright (c) 2013-2016 Chukong Technologies Inc.
 Copyright (c) 2017-2018 Xiamen Yaji Software Co., Ltd.

 https://axmolengine.github.io/

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#ifndef __CCPHYSICS_JOINT_H__
#define __CCPHYSICS_JOINT_H__

#include <functional>

#include "base/ccConfig.h"
#if AX_USE_PHYSICS

#    include "base/CCRef.h"
#    include "math/CCMath.h"

struct cpConstraint;

NS_AX_BEGIN

class Node;
class PhysicsBody;
class PhysicsWorld;

class WriteCache;

/**
 * @addtogroup physics
 * @{
 * @addtogroup physics_2d
 * @{
 */

/**
 * @brief An PhysicsJoint object connects two physics bodies together.
 */
class AX_DLL PhysicsJoint
{
protected:
    typedef std::function<void()> DelayTask;

protected:
    PhysicsJoint();
    virtual ~PhysicsJoint() = 0;

public:
    /**Get physics body a connected to this joint.*/
    PhysicsBody* getBodyA() const { return _bodyA; }

    /**Get physics body b connected to this joint.*/
    PhysicsBody* getBodyB() const { return _bodyB; }

    /**Get the physics world.*/
    PhysicsWorld* getWorld() const { return _world; }

    /**
     * Get this joint's tag.
     *
     * @return An integer number.
     */
    int getTag() const { return _tag; }

    /**
     * Set this joint's tag.
     *
     * @param tag An integer number that identifies a PhysicsJoint.
     */
    void setTag(int tag) { _tag = tag; }

    /** Determines if the joint is enable. */
    bool isEnabled() const { return _enable; }

    /** Enable/Disable the joint. */
    void setEnable(bool enable);

    /** Determines if the collision is enable. */
    bool isCollisionEnabled() const { return _collisionEnable; }

    /** Enable/disable the collision between two bodies. */
    void setCollisionEnable(bool enable);

    /** Remove the joint from the world. */
    void removeFormWorld();

    /** Set the max force between two bodies. */
    void setMaxForce(float force);

    /** Get the max force setting. */
    float getMaxForce() const { return _maxForce; }

protected:
    bool init(PhysicsBody* a, PhysicsBody* b);

    bool initJoint();

    void delay(const DelayTask& task) { _delayTasks.emplace_back(task); }

    void flushDelayTasks();

    /** Create constraints for this type joint */
    virtual bool createConstraints() { return false; }

    std::vector<cpConstraint*> _cpConstraints;
    std::vector<DelayTask> _delayTasks;
    PhysicsBody* _bodyA;
    PhysicsBody* _bodyB;
    PhysicsWorld* _world;

    WriteCache* _writeCache = nullptr;

    bool _enable;
    bool _collisionEnable;
    bool _destroyMark;
    int _tag;
    float _maxForce;

    bool _initDirty;

    friend class PhysicsBody;
    friend class PhysicsWorld;
    friend class PhysicsDebugDraw;
};

/**
 * @brief A fixed joint fuses the two bodies together at a reference point. Fixed joints are useful for creating complex
 * shapes that can be broken apart later.
 */
class AX_DLL PhysicsJointFixed : public PhysicsJoint
{
public:
    /** Create a fixed joint.

     @param a A is the body to connect.
     @param b B is the body to connect.
     @param anchr It's the pivot position.
     @return A object pointer.
     */
    static PhysicsJointFixed* construct(PhysicsBody* a, PhysicsBody* b, const Vec2& anchr);

    virtual bool createConstraints() override;

protected:
    PhysicsJointFixed() {}
    virtual ~PhysicsJointFixed() {}

    Vec2 _anchr;
};

/**
 * @brief A limit joint imposes a maximum distance between the two bodies, as if they were connected by a rope.
 */
class AX_DLL PhysicsJointLimit : public PhysicsJoint
{
public:
    /** Create a limit joint.

     @param a A is the body to connect.
     @param b B is the body to connect.
     @param anchr1 Anchr1 is the anchor point on body a.
     @param anchr2 Anchr2 is the anchor point on body b.
     @return A object pointer.
     */
    static PhysicsJointLimit* construct(PhysicsBody* a, PhysicsBody* b, const Vec2& anchr1, const Vec2& anchr2);

    /** Create a limit joint.

     @param a A is the body to connect.
     @param b B is the body to connect.
     @param anchr1 Anchr1 is the anchor point on body a.
     @param anchr2 Anchr2 is the anchor point on body b.
     @param min Define the allowed min distance of the anchor points.
     @param max Define the allowed max distance of the anchor points.
     @return A object pointer.
     */
    static PhysicsJointLimit* construct(PhysicsBody* a,
                                        PhysicsBody* b,
                                        const Vec2& anchr1,
                                        const Vec2& anchr2,
                                        float min,
                                        float max);

    /** Get the anchor point on body a.*/
    Vec2 getAnchr1() const;

    /** Set the anchor point on body a.*/
    void setAnchr1(const Vec2& anchr1);

    /** Get the anchor point on body b.*/
    Vec2 getAnchr2() const;

    /** Set the anchor point on body b.*/
    void setAnchr2(const Vec2& anchr2);

    /** Get the allowed min distance of the anchor points.*/
    float getMin() const;
    /** Set the min distance of the anchor points.*/
    void setMin(float min);

    /** Get the allowed max distance of the anchor points.*/
    float getMax() const;
    /** Set the max distance of the anchor points.*/
    void setMax(float max);

    virtual bool createConstraints() override;

protected:
    PhysicsJointLimit() {}
    virtual ~PhysicsJointLimit() {}

    Vec2 _anchr1;
    Vec2 _anchr2;
    float _min;
    float _max;
};

/**
 * @brief A pin joint allows the two bodies to independently rotate around the anchor point as if pinned together.
 */
class AX_DLL PhysicsJointPin : public PhysicsJoint
{
public:
    /** Create a pin joint.

     @param a A is the body to connect.
     @param b B is the body to connect.
     @param pivot It's the pivot position.
     @return A object pointer.
     */
    static PhysicsJointPin* construct(PhysicsBody* a, PhysicsBody* b, const Vec2& pivot);

    /** Create a pin joint.

     @param a A is the body to connect.
     @param b B is the body to connect.
     @param anchr1 Anchr1 is the anchor point on body a.
     @param anchr2 Anchr2 is the anchor point on body b.
     @return A object pointer.
     */
    static PhysicsJointPin* construct(PhysicsBody* a, PhysicsBody* b, const Vec2& anchr1, const Vec2& anchr2);

    virtual bool createConstraints() override;

protected:
    PhysicsJointPin() {}
    virtual ~PhysicsJointPin() {}

    bool _useSpecificAnchr;
    Vec2 _anchr1;
    Vec2 _anchr2;
};

/** Set the fixed distance with two bodies */
class AX_DLL PhysicsJointDistance : public PhysicsJoint
{
public:
    /** Create a fixed distance joint.

     @param a A is the body to connect.
     @param b B is the body to connect.
     @param anchr1 Anchr1 is the anchor point on body a.
     @param anchr2 Anchr2 is the anchor point on body b.
     @return A object pointer.
     */
    static PhysicsJointDistance* construct(PhysicsBody* a, PhysicsBody* b, const Vec2& anchr1, const Vec2& anchr2);

    /** Get the distance of the anchor points.*/
    float getDistance() const;
    /** Set the distance of the anchor points.*/
    void setDistance(float distance);
    virtual bool createConstraints() override;

protected:
    PhysicsJointDistance() {}
    virtual ~PhysicsJointDistance() {}

    Vec2 _anchr1;
    Vec2 _anchr2;
};

/** Connecting two physics bodies together with a spring. */
class AX_DLL PhysicsJointSpring : public PhysicsJoint
{
public:
    /** Create a fixed distance joint.

     @param a A is the body to connect.
     @param b B is the body to connect.
     @param anchr1 Anchr1 is the anchor point on body a.
     @param anchr2 Anchr2 is the anchor point on body b.
     @param stiffness It's the spring constant.
     @param damping It's how soft to make the damping of the spring.
     @return A object pointer.
     */
    static PhysicsJointSpring* construct(PhysicsBody* a,
                                         PhysicsBody* b,
                                         const Vec2& anchr1,
                                         const Vec2& anchr2,
                                         float stiffness,
                                         float damping);

    /** Get the anchor point on body a.*/
    Vec2 getAnchr1() const;

    /** Set the anchor point on body a.*/
    void setAnchr1(const Vec2& anchr1);

    /** Get the anchor point on body b.*/
    Vec2 getAnchr2() const;

    /** Set the anchor point on body b.*/
    void setAnchr2(const Vec2& anchr2);

    /** Get the distance of the anchor points.*/
    float getRestLength() const;

    /** Set the distance of the anchor points.*/
    void setRestLength(float restLength);

    /** Get the spring constant.*/
    float getStiffness() const;

    /** Set the spring constant.*/
    void setStiffness(float stiffness);

    /** Get the spring soft constant.*/
    float getDamping() const;

    /** Set the spring soft constant.*/
    void setDamping(float damping);

    virtual bool createConstraints() override;

protected:
    PhysicsJointSpring() {}
    virtual ~PhysicsJointSpring() {}

    Vec2 _anchr1;
    Vec2 _anchr2;
    float _stiffness;
    float _damping;
};

/** Attach body a to a line, and attach body b to a dot. */
class AX_DLL PhysicsJointGroove : public PhysicsJoint
{
public:
    /** Create a groove joint.

     @param a A is the body to connect.
     @param b B is the body to connect.
     @param grooveA The line begin position.
     @param grooveB The line end position.
     @param anchr2 Anchr2 is the anchor point on body b.
     @return A object pointer.
     */
    static PhysicsJointGroove* construct(PhysicsBody* a,
                                         PhysicsBody* b,
                                         const Vec2& grooveA,
                                         const Vec2& grooveB,
                                         const Vec2& anchr2);

    /** Get the line begin position*/
    Vec2 getGrooveA() const;

    /** Set the line begin position*/
    void setGrooveA(const Vec2& grooveA);

    /** Get the line end position*/
    Vec2 getGrooveB() const;

    /** Set the line end position*/
    void setGrooveB(const Vec2& grooveB);

    /** Get the anchor point on body b.*/
    Vec2 getAnchr2() const;

    /** Set the anchor point on body b.*/
    void setAnchr2(const Vec2& anchr2);

    virtual bool createConstraints() override;

protected:
    PhysicsJointGroove() {}
    virtual ~PhysicsJointGroove() {}

    Vec2 _grooveA;
    Vec2 _grooveB;
    Vec2 _anchr2;
};

/** Likes a spring joint, but works with rotary. */
class AX_DLL PhysicsJointRotarySpring : public PhysicsJoint
{
public:
    /** Create a damped rotary spring joint.

     @param a A is the body to connect.
     @param b B is the body to connect.
     @param stiffness It's the spring constant.
     @param damping It's how soft to make the damping of the spring.
     @return A object pointer.
     */
    static PhysicsJointRotarySpring* construct(PhysicsBody* a, PhysicsBody* b, float stiffness, float damping);

    /** Get the relative angle in radians from the body a to b.*/
    float getRestAngle() const;

    /** Set the relative angle in radians from the body a to b.*/
    void setRestAngle(float restAngle);

    /** Get the spring constant.*/
    float getStiffness() const;

    /** Set the spring constant.*/
    void setStiffness(float stiffness);

    /** Get the spring soft constant.*/
    float getDamping() const;

    /** Set the spring soft constant.*/
    void setDamping(float damping);

    virtual bool createConstraints() override;

protected:
    PhysicsJointRotarySpring() {}
    virtual ~PhysicsJointRotarySpring() {}

    float _stiffness;
    float _damping;
};

/** Likes a limit joint, but works with rotary. */
class AX_DLL PhysicsJointRotaryLimit : public PhysicsJoint
{
public:
    /** Create a limit rotary joint.

     @param a A is the body to connect.
     @param b B is the body to connect.
     @param min It's min rotation limit in radians.
     @param max It's max rotation limit in radians.
     @return A object pointer.
     */
    static PhysicsJointRotaryLimit* construct(PhysicsBody* a, PhysicsBody* b, float min, float max);

    /** Create a limit rotary joint.

     @param a A is the body to connect.
     @param b B is the body to connect.
     @return A object pointer.
     */
    static PhysicsJointRotaryLimit* construct(PhysicsBody* a, PhysicsBody* b);

    /** Get the min rotation limit.*/
    float getMin() const;

    /** Set the min rotation limit.*/
    void setMin(float min);

    /** Get the max rotation limit.*/
    float getMax() const;

    /** Set the max rotation limit.*/
    void setMax(float max);

    virtual bool createConstraints() override;

protected:
    PhysicsJointRotaryLimit() {}
    virtual ~PhysicsJointRotaryLimit() {}

    float _min;
    float _max;
};

/** Works like a socket wrench. */
class AX_DLL PhysicsJointRatchet : public PhysicsJoint
{
public:
    /** Create a ratchet joint.

     @param a A is the body to connect.
     @param b B is the body to connect.
     @param phase Phase is the initial offset to use when deciding where the ratchet angles are.
     @param ratchet Ratchet is the distance between "clicks".
     @return A object pointer.
     */
    static PhysicsJointRatchet* construct(PhysicsBody* a, PhysicsBody* b, float phase, float ratchet);

    /** Get the ratchet angle.*/
    float getAngle() const;

    /** Set the ratchet angle.*/
    void setAngle(float angle);

    /** Get the initial offset.*/
    float getPhase() const;

    /** Set the initial offset.*/
    void setPhase(float phase);

    /** Get the distance between "clicks".*/
    float getRatchet() const;

    /** Set the distance between "clicks".*/
    void setRatchet(float ratchet);
    virtual bool createConstraints() override;

protected:
    PhysicsJointRatchet() {}
    virtual ~PhysicsJointRatchet() {}

    float _phase;
    float _ratchet;
};

/** Keeps the angular velocity ratio of a pair of bodies constant. */
class AX_DLL PhysicsJointGear : public PhysicsJoint
{
public:
    /** Create a gear joint.

     @param a A is the body to connect.
     @param b B is the body to connect.
     @param phase Phase is the initial angular offset of the two bodies.
     @param ratio Ratio is always measured in absolute terms.
     @return A object pointer.
     */
    static PhysicsJointGear* construct(PhysicsBody* a, PhysicsBody* b, float phase, float ratio);

    /** Get the angular offset of the two bodies.*/
    float getPhase() const;

    /** Set the angular offset of the two bodies.*/
    void setPhase(float phase);

    /** Get the ratio.*/
    float getRatio() const;

    /** Set the ratio.*/
    void setRatio(float ratchet);

    virtual bool createConstraints() override;

protected:
    PhysicsJointGear() {}
    virtual ~PhysicsJointGear() {}

    float _phase;
    float _ratio;
};

/** Keeps the relative angular velocity of a pair of bodies constant. */
class AX_DLL PhysicsJointMotor : public PhysicsJoint
{
public:
    /** Create a motor joint.

     @param a A is the body to connect.
     @param b B is the body to connect.
     @param rate Rate is the desired relative angular velocity.
     @return A object pointer.
     */
    static PhysicsJointMotor* construct(PhysicsBody* a, PhysicsBody* b, float rate);

    /** Get the relative angular velocity.*/
    float getRate() const;

    /** Set the relative angular velocity.*/
    void setRate(float rate);
    virtual bool createConstraints() override;

protected:
    PhysicsJointMotor() {}
    virtual ~PhysicsJointMotor() {}

    float _rate;
};

/** @} */
/** @} */

NS_AX_END

#endif  // AX_USE_PHYSICS
#endif  // __CCPHYSICS_JOINT_H__