axmol/core/physics/CCPhysicsWorld.h

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#ifndef __CCPHYSICS_WORLD_H__
#define __CCPHYSICS_WORLD_H__

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

#    include <list>
#    include "base/CCVector.h"
#    include "math/CCMath.h"
#    include "physics/CCPhysicsBody.h"

struct cpSpace;

NS_CC_BEGIN

class PhysicsBody;
class PhysicsJoint;
class PhysicsShape;
class PhysicsContact;

class Director;
class Node;
class Sprite;
class Scene;
class DrawNode;
class PhysicsDebugDraw;
class EventDispatcher;

class PhysicsWorld;

typedef struct PhysicsRayCastInfo
{
    PhysicsShape* shape;
    Vec2 start;
    Vec2 end;  ///< in lua, it's name is "ended"
    Vec2 contact;
    Vec2 normal;

    // FIXME: correct thing to do is use `cpFloat` instead of float.
    // but in order to do so, we should include "chipmunk_types.h"
    // in Chipmunk v7.0, chipmunk_types includes all the mac types that
    // conflicts with cocos2d Vec2, Point,... etc types. And all the CocosStudio
    // lib will need to use the `cocos2d::` namespace prefix. And it is easier to do this
    // than change all the cocosstudio library (and also users code)
    float fraction;
    void* data;
} PhysicsRayCastInfo;

/**
 * @brief Called for each fixture found in the query. You control how the ray cast
 * proceeds by returning a float:
 * return true: continue
 * return false: terminate the ray cast
 * @param fixture the fixture hit by the ray
 * @param point the point of initial intersection
 * @param normal the normal vector at the point of intersection
 * @return true to continue, false to terminate
 */
typedef std::function<bool(PhysicsWorld& world, const PhysicsRayCastInfo& info, void* data)> PhysicsRayCastCallbackFunc;
typedef std::function<bool(PhysicsWorld&, PhysicsShape&, void*)> PhysicsQueryRectCallbackFunc;
typedef PhysicsQueryRectCallbackFunc PhysicsQueryPointCallbackFunc;

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

/**
 * @class PhysicsWorld CCPhysicsWorld.h
 * @brief An PhysicsWorld object simulates collisions and other physical properties. You do not create PhysicsWorld
 * objects directly; instead, you can get it from an Scene object.
 */
class CC_DLL PhysicsWorld
{
public:
    static const int DEBUGDRAW_NONE;     ///< draw nothing
    static const int DEBUGDRAW_SHAPE;    ///< draw shapes
    static const int DEBUGDRAW_JOINT;    ///< draw joints
    static const int DEBUGDRAW_CONTACT;  ///< draw contact
    static const int DEBUGDRAW_ALL;      ///< draw all

public:
    /**
     * Adds a joint to this physics world.
     *
     * This joint will be added to this physics world at next frame.
     * @attention If this joint is already added to another physics world, it will be removed from that world first and
     * then add to this world.
     * @param   joint   A pointer to an existing PhysicsJoint object.
     */
    virtual void addJoint(PhysicsJoint* joint);

    /**
     * Remove a joint from this physics world.
     *
     * If this world is not locked, the joint is removed immediately, otherwise at next frame.
     * If this joint is connected with a body, it will be removed from the body also.
     * @param   joint   A pointer to an existing PhysicsJoint object.
     * @param   destroy   true this joint will be destroyed after remove from this world, false otherwise.
     */
    virtual void removeJoint(PhysicsJoint* joint, bool destroy = true);

    /**
     * Remove all joints from this physics world.
     *
     * @attention This function is invoked in the destructor of this physics world, you do not use this api in common.
     * @param   destroy   true all joints will be destroyed after remove from this world, false otherwise.
     */
    virtual void removeAllJoints(bool destroy = true);

    /**
     * Remove a body from this physics world.
     *
     * If this world is not locked, the body is removed immediately, otherwise at next frame.
     * @attention If this body has joints, those joints will be removed also.
     * @param   body   A pointer to an existing PhysicsBody object.
     */
    virtual void removeBody(PhysicsBody* body);

    /**
     * Remove body by tag.
     *
     * If this world is not locked, the object is removed immediately, otherwise at next frame.
     * @attention If this body has joints, those joints will be removed also.
     * @param   tag   An integer number that identifies a PhysicsBody object.
     */
    virtual void removeBody(int tag);

    /**
     * Remove all bodies from physics world.
     *
     * If this world is not locked, those body are removed immediately, otherwise at next frame.
     */
    virtual void removeAllBodies();

    /**
     * Searches for physics shapes that intersects the ray.
     *
     * Query this physics world along the line segment from start to end.
     * @param   func   Func is called for each shape found.
     * @param   start   A Vec2 object contains the begin position of the ray.
     * @param   end   A Vec2 object contains the end position of the ray.
     * @param   data   User defined data, it is passed to func.
     */
    void rayCast(PhysicsRayCastCallbackFunc func, const Vec2& start, const Vec2& end, void* data);

    /**
     * Searches for physics shapes that contains in the rect.
     *
     * Query this physics world to find all shapes overlap rect.
     * @param   func   Func is called for each shape whose bounding box overlaps rect.
     * @param   rect   A Rect object contains a rectangle's x, y, width and height.
     * @param   data   User defined data, it is passed to func.
     */
    void queryRect(PhysicsQueryRectCallbackFunc func, const Rect& rect, void* data);

    /**
     * Searches for physics shapes that contains the point.
     *
     * @attention The point must lie inside a shape.
     * @param   func   Func is called for each shape contains the point.
     * @param   point   A Vec2 object contains the position of the point.
     * @param   data   User defined data, it is passed to func.
     */
    void queryPoint(PhysicsQueryPointCallbackFunc func, const Vec2& point, void* data);

    /**
     * Get physics shapes that contains the point.
     *
     * All shapes contains the point will be pushed in a Vector<PhysicsShape*> object.
     * @attention The point must lie inside a shape.
     * @param   point   A Vec2 object contains the position of the point.
     * @return A Vector<PhysicsShape*> object contains all found PhysicsShape pointer.
     */
    Vector<PhysicsShape*> getShapes(const Vec2& point) const;

    /**
     * Get the nearest physics shape that contains the point.
     *
     * Query this physics world at point and return the closest shape.
     * @param   point   A Vec2 object contains the position of the point.
     * @return A PhysicsShape object pointer or nullptr if no shapes were found
     */
    PhysicsShape* getShape(const Vec2& point) const;

    /**
     * Get all the bodies that in this physics world.
     *
     * @return A Vector<PhysicsBody*>& object contains all bodies in this physics world.
     */
    const Vector<PhysicsBody*>& getAllBodies() const;

    /**
     * Get a body by tag.
     *
     * @param   tag   An integer number that identifies a PhysicsBody object.
     * @return A PhysicsBody object pointer or nullptr if no shapes were found.
     */
    PhysicsBody* getBody(int tag) const;

    /**
     * Get a scene contain this physics world.
     *
     * @attention This value is initialized in constructor
     * @return A Scene object reference.
     */
    Scene& getScene() const { return *_scene; }

    /**
     * Get the gravity value of this physics world.
     *
     * @return A Vec2 object.
     */
    Vec2 getGravity() const { return _gravity; }

    /**
     * set the gravity value of this physics world.
     *
     * @param gravity A gravity value of this physics world.
     */
    void setGravity(const Vec2& gravity);

    /**
     * Set the speed of this physics world.
     *
     * @attention if you setAutoStep(false), this won't work.
     * @param speed  A float number. Speed is the rate at which the simulation executes. default value is 1.0.
     */
    void setSpeed(float speed)
    {
        if (speed >= 0.0f)
        {
            _speed = speed;
        }
    }

    /**
     * Get the speed of this physics world.
     *
     * @return A float number.
     */
    float getSpeed() { return _speed; }

    /**
     * Set the update rate of this physics world
     *
     * Update rate is the value of EngineUpdateTimes/PhysicsWorldUpdateTimes.
     * Set it higher can improve performance, set it lower can improve accuracy of physics world simulation.
     * @attention if you setAutoStep(false), this won't work.
     * @param rate An integer number, default value is 1.0.
     */
    void setUpdateRate(int rate)
    {
        if (rate > 0)
        {
            _updateRate = rate;
        }
    }

    /**
     * Get the update rate of this physics world.
     *
     * @return An integer number.
     */
    int getUpdateRate() { return _updateRate; }

    /**
     * set the number of substeps in an update of the physics world.
     *
     * One physics update will be divided into several substeps to increase its accuracy.
     * @param steps An integer number, default value is 1.
     */
    void setSubsteps(int steps);

    /**
     * Get the number of substeps of this physics world.
     *
     * @return An integer number.
     */
    int getSubsteps() const { return _substeps; }

    /**
     * set the number of update of the physics world in a second.
     * 0 - disable fixed step system
     * default value is 0
     */
    void setFixedUpdateRate(int updatesPerSecond)
    {
        if (updatesPerSecond > 0)
        {
            _fixedRate = updatesPerSecond;
        }
    }
    /** get the number of substeps */
    int getFixedUpdateRate() const { return _fixedRate; }

    /**
     * Set the debug draw mask of this physics world.
     *
     * This physics world will draw shapes and joints by DrawNode according to mask.
     * @param mask Mask has four value:DEBUGDRAW_NONE, DEBUGDRAW_SHAPE, DEBUGDRAW_JOINT, DEBUGDRAW_CONTACT and
     * DEBUGDRAW_ALL, default is DEBUGDRAW_NONE
     */
    void setDebugDrawMask(int mask);

    /**
     * set the callback which invoked before update of each object in physics world.
     */
    void setPreUpdateCallback(const std::function<void()>& callback);

    /**
     * set the callback which invoked after update of each object in physics world.
     */
    void setPostUpdateCallback(const std::function<void()>& callback);

    /**
     * Get the debug draw mask.
     *
     * @return An integer number.
     */
    int getDebugDrawMask() { return _debugDrawMask; }

    /**
     * To control the step of physics.
     *
     * If you want control it by yourself( fixed-timestep for example ), you can set this to false and call step by
     * yourself.
     * @attention If you set auto step to false, setSpeed setSubsteps and setUpdateRate won't work, you need to control
     * the time step by yourself.
     * @param autoStep A bool object, default value is true.
     */
    void setAutoStep(bool autoStep) { _autoStep = autoStep; }

    /**
     * Get the auto step of this physics world.
     *
     * @return A bool object.
     */
    bool isAutoStep() { return _autoStep; }

    /**
     * The step for physics world.
     *
     * The times passing for simulate the physics.
     * @attention You need to setAutoStep(false) first before it can work.
     * @param   delta   A float number.
     */
    void step(float delta);

protected:
    static PhysicsWorld* construct(Scene* scene);
    bool init();

    virtual void addBody(PhysicsBody* body);
    virtual void addShape(PhysicsShape* shape);
    virtual void removeShape(PhysicsShape* shape);
    virtual void update(float delta, bool userCall = false);

    virtual void debugDraw();

    virtual bool collisionBeginCallback(PhysicsContact& contact);
    virtual bool collisionPreSolveCallback(PhysicsContact& contact);
    virtual void collisionPostSolveCallback(PhysicsContact& contact);
    virtual void collisionSeparateCallback(PhysicsContact& contact);

    virtual void doAddBody(PhysicsBody* body);
    virtual void doRemoveBody(PhysicsBody* body);
    virtual void doRemoveJoint(PhysicsJoint* joint);
    virtual void addBodyOrDelay(PhysicsBody* body);
    virtual void removeBodyOrDelay(PhysicsBody* body);
    virtual void updateBodies();
    virtual void updateJoints();

protected:
    Vec2 _gravity;
    float _speed;
    int _updateRate;
    int _updateRateCount;
    float _updateTime;
    int _substeps;
    int _fixedRate;
    cpSpace* _cpSpace;

    bool _updateBodyTransform;
    Vector<PhysicsBody*> _bodies;
    std::list<PhysicsJoint*> _joints;
    Scene* _scene;

    bool _autoStep;
    DrawNode* _debugDraw;
    int _debugDrawMask;

    EventDispatcher* _eventDispatcher;

    Vector<PhysicsBody*> _delayAddBodies;
    Vector<PhysicsBody*> _delayRemoveBodies;
    std::vector<PhysicsJoint*> _delayAddJoints;
    std::vector<PhysicsJoint*> _delayRemoveJoints;

    std::function<void()> _preUpdateCallback;
    std::function<void()> _postUpdateCallback;

protected:
    PhysicsWorld();
    virtual ~PhysicsWorld();

    void beforeSimulation(Node* node,
                          const Mat4& parentToWorldTransform,
                          float nodeParentScaleX,
                          float nodeParentScaleY,
                          float parentRotation);
    void afterSimulation(Node* node, const Mat4& parentToWorldTransform, float parentRotation);

    friend class Node;
    friend class Sprite;
    friend class Scene;
    friend class Director;
    friend class PhysicsBody;
    friend class PhysicsShape;
    friend class PhysicsJoint;
    friend class PhysicsWorldCallback;
    friend class PhysicsDebugDraw;
};

extern const float CC_DLL PHYSICS_INFINITY;

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

NS_CC_END

#endif  // CC_USE_PHYSICS
#endif  // __CCPHYSICS_WORLD_H__