axmol/core/physics/PhysicsContact.h

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 Copyright (c) 2017-2018 Xiamen Yaji Software Co., Ltd.

 https://axmolengine.github.io/

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#ifndef __CCPHYSICS_CONTACT_H__
#define __CCPHYSICS_CONTACT_H__

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

#    include "base/Ref.h"
#    include "math/Math.h"
#    include "base/EventListenerCustom.h"
#    include "base/Event.h"
#    include "base/EventCustom.h"

NS_AX_BEGIN

class PhysicsShape;
class PhysicsBody;
class PhysicsWorld;

typedef struct AX_DLL PhysicsContactData
{
    static const int POINT_MAX = 4;
    Vec2 points[POINT_MAX];
    int count;
    Vec2 normal;

    PhysicsContactData() : count(0) {}
} PhysicsContactData;

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

/**
 * @brief Contact information.

 * It will created automatically when two shape contact with each other. And it will destroyed automatically when two
 shape separated.
 */
class AX_DLL PhysicsContact : public EventCustom
{
public:
    enum class EventCode
    {
        NONE,
        BEGIN,
        PRESOLVE,
        POSTSOLVE,
        SEPARATE
    };

    /** Get contact shape A. */
    PhysicsShape* getShapeA() const { return _shapeA; }

    /** Get contact shape B. */
    PhysicsShape* getShapeB() const { return _shapeB; }

    /** Get contact data. */
    const PhysicsContactData* getContactData() const { return _contactData; }

    /** Get previous contact data */
    const PhysicsContactData* getPreContactData() const { return _preContactData; }

    /**
     * Get data.
     * @lua NA
     */
    void* getData() const { return _data; }

    /**
     * @brief Set data to contact.

     * You must manage the memory yourself, Generally you can set data at contact begin, and destroy it at contact
     separate.
     *
     * @lua NA
     */
    void setData(void* data) { _data = data; }

    /** Get the event code */
    EventCode getEventCode() const { return _eventCode; };

private:
    static PhysicsContact* construct(PhysicsShape* a, PhysicsShape* b);
    bool init(PhysicsShape* a, PhysicsShape* b);

    void setEventCode(EventCode eventCode) { _eventCode = eventCode; };
    bool isNotificationEnabled() const { return _notificationEnable; }
    void setNotificationEnable(bool enable) { _notificationEnable = enable; }
    PhysicsWorld* getWorld() const { return _world; }
    void setWorld(PhysicsWorld* world) { _world = world; }
    void setResult(bool result) { _result = result; }
    bool resetResult()
    {
        bool ret = _result;
        _result  = true;
        return ret;
    }

    void generateContactData();

private:
    PhysicsContact();
    ~PhysicsContact();

private:
    PhysicsWorld* _world;
    PhysicsShape* _shapeA;
    PhysicsShape* _shapeB;
    EventCode _eventCode;
    bool _notificationEnable;
    bool _result;

    void* _data;
    void* _contactInfo;
    PhysicsContactData* _contactData;
    PhysicsContactData* _preContactData;

    friend class EventListenerPhysicsContact;
    friend class PhysicsWorldCallback;
    friend class PhysicsWorld;
};

/**
 * @brief Presolve value generated when onContactPreSolve called.
 */
class AX_DLL PhysicsContactPreSolve
{
public:
    /** Get restitution between two bodies.*/
    float getRestitution() const;
    /** Get friction between two bodies.*/
    float getFriction() const;
    /** Get surface velocity between two bodies.*/
    Vec2 getSurfaceVelocity() const;
    /** Set the restitution.*/
    void setRestitution(float restitution);
    /** Set the friction.*/
    void setFriction(float friction);
    /** Set the surface velocity.*/
    void setSurfaceVelocity(const Vec2& velocity);
    /** Ignore the rest of the contact presolve and postsolve callbacks. */
    void ignore();

private:
    PhysicsContactPreSolve(void* contactInfo);
    ~PhysicsContactPreSolve();

private:
    void* _contactInfo;

    friend class EventListenerPhysicsContact;
};

/**
 * @brief Postsolve value generated when onContactPostSolve called.
 */
class AX_DLL PhysicsContactPostSolve
{
public:
    /** Get restitution between two bodies.*/
    float getRestitution() const;
    /** Get friction between two bodies.*/
    float getFriction() const;
    /** Get surface velocity between two bodies.*/
    Vec2 getSurfaceVelocity() const;

private:
    PhysicsContactPostSolve(void* contactInfo);
    ~PhysicsContactPostSolve();

private:
    void* _contactInfo;

    friend class EventListenerPhysicsContact;
};

/** Contact listener. It will receive all the contact callbacks. */
class AX_DLL EventListenerPhysicsContact : public EventListenerCustom
{
public:
    /** Create the listener. */
    static EventListenerPhysicsContact* create();

    /** Check the listener is available.

     * @return True if there's one available callback function at least, false if there's no one.
     */
    virtual bool checkAvailable() override;

    /** Clone an object from this listener.*/
    virtual EventListenerPhysicsContact* clone() override;

protected:
    /**
     * It will be call when two body have contact.
     * if return false, it will not invoke callbacks.
     */
    virtual bool hitTest(PhysicsShape* shapeA, PhysicsShape* shapeB);

public:
    /**
     * @brief It will called at two shapes start to contact, and only call it once.
     */
    std::function<bool(PhysicsContact& contact)> onContactBegin;
    /**
     * @brief Two shapes are touching during this step. Return false from the callback to make world ignore the
     * collision this step or true to process it normally. Additionally, you may override collision values, restitution,
     * or surface velocity values.
     */
    std::function<bool(PhysicsContact& contact, PhysicsContactPreSolve& solve)> onContactPreSolve;
    /**
     * @brief Two shapes are touching and their collision response has been processed. You can retrieve the collision
     * impulse or kinetic energy at this time if you want to use it to calculate sound volumes or damage amounts. See
     * cpArbiter for more info
     */
    std::function<void(PhysicsContact& contact, const PhysicsContactPostSolve& solve)> onContactPostSolve;
    /**
     * @brief It will called at two shapes separated, and only call it once.
     * onContactBegin and onContactSeparate will called in pairs.
     */
    std::function<void(PhysicsContact& contact)> onContactSeparate;

protected:
    bool init();
    void onEvent(EventCustom* event);

protected:
    EventListenerPhysicsContact();
    virtual ~EventListenerPhysicsContact();

    friend class PhysicsWorld;
};

/** This event listener only be called when bodyA and bodyB have contacts. */
class AX_DLL EventListenerPhysicsContactWithBodies : public EventListenerPhysicsContact
{
public:
    /** Create the listener. */
    static EventListenerPhysicsContactWithBodies* create(PhysicsBody* bodyA, PhysicsBody* bodyB);

    virtual bool hitTest(PhysicsShape* shapeA, PhysicsShape* shapeB) override;

    virtual EventListenerPhysicsContactWithBodies* clone() override;

protected:
    PhysicsBody* _a;
    PhysicsBody* _b;

protected:
    EventListenerPhysicsContactWithBodies();
    virtual ~EventListenerPhysicsContactWithBodies();
};

/** This event listener only be called when shapeA and shapeB have contacts. */
class AX_DLL EventListenerPhysicsContactWithShapes : public EventListenerPhysicsContact
{
public:
    /** Create the listener. */
    static EventListenerPhysicsContactWithShapes* create(PhysicsShape* shapeA, PhysicsShape* shapeB);

    virtual bool hitTest(PhysicsShape* shapeA, PhysicsShape* shapeB) override;
    virtual EventListenerPhysicsContactWithShapes* clone() override;

protected:
    PhysicsShape* _a;
    PhysicsShape* _b;

protected:
    EventListenerPhysicsContactWithShapes();
    virtual ~EventListenerPhysicsContactWithShapes();
};

/** This event listener only be called when shapeA or shapeB is in the group your specified */
class AX_DLL EventListenerPhysicsContactWithGroup : public EventListenerPhysicsContact
{
public:
    /** Create the listener. */
    static EventListenerPhysicsContactWithGroup* create(int group);

    virtual bool hitTest(PhysicsShape* shapeA, PhysicsShape* shapeB) override;
    virtual EventListenerPhysicsContactWithGroup* clone() override;

protected:
    int _group;

protected:
    EventListenerPhysicsContactWithGroup();
    virtual ~EventListenerPhysicsContactWithGroup();
};

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

NS_AX_END

#endif  // AX_USE_PHYSICS
#endif  //__CCPHYSICS_CONTACT_H__