axmol/external/Box2D/Dynamics/b2Body.h

/*
* Copyright (c) 2006-2011 Erin Catto http://www.box2d.org
*
* This software is provided 'as-is', without any express or implied
* warranty.  In no event will the authors be held liable for any damages
* arising from the use of this software.
* Permission is granted to anyone to use this software for any purpose,
* including commercial applications, and to alter it and redistribute it
* freely, subject to the following restrictions:
* 1. The origin of this software must not be misrepresented; you must not
* claim that you wrote the original software. If you use this software
* in a product, an acknowledgment in the product documentation would be
* appreciated but is not required.
* 2. Altered source versions must be plainly marked as such, and must not be
* misrepresented as being the original software.
* 3. This notice may not be removed or altered from any source distribution.
*/

#ifndef B2_BODY_H
#define B2_BODY_H

#include <Box2D/Common/b2Math.h>
#include <Box2D/Collision/Shapes/b2Shape.h>
#include <memory>

class b2Fixture;
class b2Joint;
class b2Contact;
class b2Controller;
class b2World;
struct b2FixtureDef;
struct b2JointEdge;
struct b2ContactEdge;

/// The body type.
/// static: zero mass, zero velocity, may be manually moved
/// kinematic: zero mass, non-zero velocity set by user, moved by solver
/// dynamic: positive mass, non-zero velocity determined by forces, moved by solver
enum b2BodyType
{
    b2_staticBody = 0,
    b2_kinematicBody,
    b2_dynamicBody

    // TODO_ERIN
    //b2_bulletBody,
};

/// A body definition holds all the data needed to construct a rigid body.
/// You can safely re-use body definitions. Shapes are added to a body after construction.
struct b2BodyDef
{
    /// This constructor sets the body definition default values.
    b2BodyDef()
    {
        userData = NULL;
        position.Set(0.0f, 0.0f);
        angle = 0.0f;
        linearVelocity.Set(0.0f, 0.0f);
        angularVelocity = 0.0f;
        linearDamping = 0.0f;
        angularDamping = 0.0f;
        allowSleep = true;
        awake = true;
        fixedRotation = false;
        bullet = false;
        type = b2_staticBody;
        active = true;
        gravityScale = 1.0f;
    }

    /// The body type: static, kinematic, or dynamic.
    /// Note: if a dynamic body would have zero mass, the mass is set to one.
    b2BodyType type;

    /// The world position of the body. Avoid creating bodies at the origin
    /// since this can lead to many overlapping shapes.
    b2Vec2 position;

    /// The world angle of the body in radians.
    float32 angle;

    /// The linear velocity of the body's origin in world co-ordinates.
    b2Vec2 linearVelocity;

    /// The angular velocity of the body.
    float32 angularVelocity;

    /// Linear damping is use to reduce the linear velocity. The damping parameter
    /// can be larger than 1.0f but the damping effect becomes sensitive to the
    /// time step when the damping parameter is large.
    float32 linearDamping;

    /// Angular damping is use to reduce the angular velocity. The damping parameter
    /// can be larger than 1.0f but the damping effect becomes sensitive to the
    /// time step when the damping parameter is large.
    float32 angularDamping;

    /// Set this flag to false if this body should never fall asleep. Note that
    /// this increases CPU usage.
    bool allowSleep;

    /// Is this body initially awake or sleeping?
    bool awake;

    /// Should this body be prevented from rotating? Useful for characters.
    bool fixedRotation;

    /// Is this a fast moving body that should be prevented from tunneling through
    /// other moving bodies? Note that all bodies are prevented from tunneling through
    /// kinematic and static bodies. This setting is only considered on dynamic bodies.
    /// @warning You should use this flag sparingly since it increases processing time.
    bool bullet;

    /// Does this body start out active?
    bool active;

    /// Use this to store application specific body data.
    void* userData;

    /// Scale the gravity applied to this body.
    float32 gravityScale;
};

/// A rigid body. These are created via b2World::CreateBody.
class b2Body
{
public:
    /// Creates a fixture and attach it to this body. Use this function if you need
    /// to set some fixture parameters, like friction. Otherwise you can create the
    /// fixture directly from a shape.
    /// If the density is non-zero, this function automatically updates the mass of the body.
    /// Contacts are not created until the next time step.
    /// @param def the fixture definition.
    /// @warning This function is locked during callbacks.
    b2Fixture* CreateFixture(const b2FixtureDef* def);

    /// Creates a fixture from a shape and attach it to this body.
    /// This is a convenience function. Use b2FixtureDef if you need to set parameters
    /// like friction, restitution, user data, or filtering.
    /// If the density is non-zero, this function automatically updates the mass of the body.
    /// @param shape the shape to be cloned.
    /// @param density the shape density (set to zero for static bodies).
    /// @warning This function is locked during callbacks.
    b2Fixture* CreateFixture(const b2Shape* shape, float32 density);

    /// Destroy a fixture. This removes the fixture from the broad-phase and
    /// destroys all contacts associated with this fixture. This will
    /// automatically adjust the mass of the body if the body is dynamic and the
    /// fixture has positive density.
    /// All fixtures attached to a body are implicitly destroyed when the body is destroyed.
    /// @param fixture the fixture to be removed.
    /// @warning This function is locked during callbacks.
    void DestroyFixture(b2Fixture* fixture);

    /// Set the position of the body's origin and rotation.
    /// This breaks any contacts and wakes the other bodies.
    /// Manipulating a body's transform may cause non-physical behavior.
    /// @param position the world position of the body's local origin.
    /// @param angle the world rotation in radians.
    void SetTransform(const b2Vec2& position, float32 angle);

    /// Get the body transform for the body's origin.
    /// @return the world transform of the body's origin.
    const b2Transform& GetTransform() const;

    /// Get the world body origin position.
    /// @return the world position of the body's origin.
    const b2Vec2& GetPosition() const;

    /// Get the angle in radians.
    /// @return the current world rotation angle in radians.
    float32 GetAngle() const;

    /// Get the world position of the center of mass.
    const b2Vec2& GetWorldCenter() const;

    /// Get the local position of the center of mass.
    const b2Vec2& GetLocalCenter() const;

    /// Set the linear velocity of the center of mass.
    /// @param v the new linear velocity of the center of mass.
    void SetLinearVelocity(const b2Vec2& v);

    /// Get the linear velocity of the center of mass.
    /// @return the linear velocity of the center of mass.
    b2Vec2 GetLinearVelocity() const;

    /// Set the angular velocity.
    /// @param omega the new angular velocity in radians/second.
    void SetAngularVelocity(float32 omega);

    /// Get the angular velocity.
    /// @return the angular velocity in radians/second.
    float32 GetAngularVelocity() const;

    /// Apply a force at a world point. If the force is not
    /// applied at the center of mass, it will generate a torque and
    /// affect the angular velocity. This wakes up the body.
    /// @param force the world force vector, usually in Newtons (N).
    /// @param point the world position of the point of application.
    void ApplyForce(const b2Vec2& force, const b2Vec2& point);

    /// Apply a force to the center of mass. This wakes up the body.
    /// @param force the world force vector, usually in Newtons (N).
    void ApplyForceToCenter(const b2Vec2& force);

    /// Apply a torque. This affects the angular velocity
    /// without affecting the linear velocity of the center of mass.
    /// This wakes up the body.
    /// @param torque about the z-axis (out of the screen), usually in N-m.
    void ApplyTorque(float32 torque);

    /// Apply an impulse at a point. This immediately modifies the velocity.
    /// It also modifies the angular velocity if the point of application
    /// is not at the center of mass. This wakes up the body.
    /// @param impulse the world impulse vector, usually in N-seconds or kg-m/s.
    /// @param point the world position of the point of application.
    void ApplyLinearImpulse(const b2Vec2& impulse, const b2Vec2& point);

    /// Apply an angular impulse.
    /// @param impulse the angular impulse in units of kg*m*m/s
    void ApplyAngularImpulse(float32 impulse);

    /// Get the total mass of the body.
    /// @return the mass, usually in kilograms (kg).
    float32 GetMass() const;

    /// Get the rotational inertia of the body about the local origin.
    /// @return the rotational inertia, usually in kg-m^2.
    float32 GetInertia() const;

    /// Get the mass data of the body.
    /// @return a struct containing the mass, inertia and center of the body.
    void GetMassData(b2MassData* data) const;

    /// Set the mass properties to override the mass properties of the fixtures.
    /// Note that this changes the center of mass position.
    /// Note that creating or destroying fixtures can also alter the mass.
    /// This function has no effect if the body isn't dynamic.
    /// @param massData the mass properties.
    void SetMassData(const b2MassData* data);

    /// This resets the mass properties to the sum of the mass properties of the fixtures.
    /// This normally does not need to be called unless you called SetMassData to override
    /// the mass and you later want to reset the mass.
    void ResetMassData();

    /// Get the world coordinates of a point given the local coordinates.
    /// @param localPoint a point on the body measured relative the the body's origin.
    /// @return the same point expressed in world coordinates.
    b2Vec2 GetWorldPoint(const b2Vec2& localPoint) const;

    /// Get the world coordinates of a vector given the local coordinates.
    /// @param localVector a vector fixed in the body.
    /// @return the same vector expressed in world coordinates.
    b2Vec2 GetWorldVector(const b2Vec2& localVector) const;

    /// Gets a local point relative to the body's origin given a world point.
    /// @param a point in world coordinates.
    /// @return the corresponding local point relative to the body's origin.
    b2Vec2 GetLocalPoint(const b2Vec2& worldPoint) const;

    /// Gets a local vector given a world vector.
    /// @param a vector in world coordinates.
    /// @return the corresponding local vector.
    b2Vec2 GetLocalVector(const b2Vec2& worldVector) const;

    /// Get the world linear velocity of a world point attached to this body.
    /// @param a point in world coordinates.
    /// @return the world velocity of a point.
    b2Vec2 GetLinearVelocityFromWorldPoint(const b2Vec2& worldPoint) const;

    /// Get the world velocity of a local point.
    /// @param a point in local coordinates.
    /// @return the world velocity of a point.
    b2Vec2 GetLinearVelocityFromLocalPoint(const b2Vec2& localPoint) const;

    /// Get the linear damping of the body.
    float32 GetLinearDamping() const;

    /// Set the linear damping of the body.
    void SetLinearDamping(float32 linearDamping);

    /// Get the angular damping of the body.
    float32 GetAngularDamping() const;

    /// Set the angular damping of the body.
    void SetAngularDamping(float32 angularDamping);

    /// Get the gravity scale of the body.
    float32 GetGravityScale() const;

    /// Set the gravity scale of the body.
    void SetGravityScale(float32 scale);

    /// Set the type of this body. This may alter the mass and velocity.
    void SetType(b2BodyType type);

    /// Get the type of this body.
    b2BodyType GetType() const;

    /// Should this body be treated like a bullet for continuous collision detection?
    void SetBullet(bool flag);

    /// Is this body treated like a bullet for continuous collision detection?
    bool IsBullet() const;

    /// You can disable sleeping on this body. If you disable sleeping, the
    /// body will be woken.
    void SetSleepingAllowed(bool flag);

    /// Is this body allowed to sleep
    bool IsSleepingAllowed() const;

    /// Set the sleep state of the body. A sleeping body has very
    /// low CPU cost.
    /// @param flag set to true to put body to sleep, false to wake it.
    void SetAwake(bool flag);

    /// Get the sleeping state of this body.
    /// @return true if the body is sleeping.
    bool IsAwake() const;

    /// Set the active state of the body. An inactive body is not
    /// simulated and cannot be collided with or woken up.
    /// If you pass a flag of true, all fixtures will be added to the
    /// broad-phase.
    /// If you pass a flag of false, all fixtures will be removed from
    /// the broad-phase and all contacts will be destroyed.
    /// Fixtures and joints are otherwise unaffected. You may continue
    /// to create/destroy fixtures and joints on inactive bodies.
    /// Fixtures on an inactive body are implicitly inactive and will
    /// not participate in collisions, ray-casts, or queries.
    /// Joints connected to an inactive body are implicitly inactive.
    /// An inactive body is still owned by a b2World object and remains
    /// in the body list.
    void SetActive(bool flag);

    /// Get the active state of the body.
    bool IsActive() const;

    /// Set this body to have fixed rotation. This causes the mass
    /// to be reset.
    void SetFixedRotation(bool flag);

    /// Does this body have fixed rotation?
    bool IsFixedRotation() const;

    /// Get the list of all fixtures attached to this body.
    b2Fixture* GetFixtureList();
    const b2Fixture* GetFixtureList() const;

    /// Get the list of all joints attached to this body.
    b2JointEdge* GetJointList();
    const b2JointEdge* GetJointList() const;

    /// Get the list of all contacts attached to this body.
    /// @warning this list changes during the time step and you may
    /// miss some collisions if you don't use b2ContactListener.
    b2ContactEdge* GetContactList();
    const b2ContactEdge* GetContactList() const;

    /// Get the next body in the world's body list.
    b2Body* GetNext();
    const b2Body* GetNext() const;

    /// Get the user data pointer that was provided in the body definition.
    void* GetUserData() const;

    /// Set the user data. Use this to store your application specific data.
    void SetUserData(void* data);

    /// Get the parent world of this body.
    b2World* GetWorld();
    const b2World* GetWorld() const;

    /// Dump this body to a log file
    void Dump();

private:

    friend class b2World;
    friend class b2Island;
    friend class b2ContactManager;
    friend class b2ContactSolver;
    friend class b2Contact;
    
    friend class b2DistanceJoint;
    friend class b2GearJoint;
    friend class b2WheelJoint;
    friend class b2MouseJoint;
    friend class b2PrismaticJoint;
    friend class b2PulleyJoint;
    friend class b2RevoluteJoint;
    friend class b2WeldJoint;
    friend class b2FrictionJoint;
    friend class b2RopeJoint;

    // m_flags
    enum
    {
        e_islandFlag        = 0x0001,
        e_awakeFlag            = 0x0002,
        e_autoSleepFlag        = 0x0004,
        e_bulletFlag        = 0x0008,
        e_fixedRotationFlag    = 0x0010,
        e_activeFlag        = 0x0020,
        e_toiFlag            = 0x0040
    };

    b2Body(const b2BodyDef* bd, b2World* world);
    ~b2Body();

    void SynchronizeFixtures();
    void SynchronizeTransform();

    // This is used to prevent connected bodies from colliding.
    // It may lie, depending on the collideConnected flag.
    bool ShouldCollide(const b2Body* other) const;

    void Advance(float32 t);

    b2BodyType m_type;

    uint16 m_flags;

    int32 m_islandIndex;

    b2Transform m_xf;        // the body origin transform
    b2Sweep m_sweep;        // the swept motion for CCD

    b2Vec2 m_linearVelocity;
    float32 m_angularVelocity;

    b2Vec2 m_force;
    float32 m_torque;

    b2World* m_world;
    b2Body* m_prev;
    b2Body* m_next;

    b2Fixture* m_fixtureList;
    int32 m_fixtureCount;

    b2JointEdge* m_jointList;
    b2ContactEdge* m_contactList;

    float32 m_mass, m_invMass;

    // Rotational inertia about the center of mass.
    float32 m_I, m_invI;

    float32 m_linearDamping;
    float32 m_angularDamping;
    float32 m_gravityScale;

    float32 m_sleepTime;

    void* m_userData;
};

inline b2BodyType b2Body::GetType() const
{
    return m_type;
}

inline const b2Transform& b2Body::GetTransform() const
{
    return m_xf;
}

inline const b2Vec2& b2Body::GetPosition() const
{
    return m_xf.p;
}

inline float32 b2Body::GetAngle() const
{
    return m_sweep.a;
}

inline const b2Vec2& b2Body::GetWorldCenter() const
{
    return m_sweep.c;
}

inline const b2Vec2& b2Body::GetLocalCenter() const
{
    return m_sweep.localCenter;
}

inline void b2Body::SetLinearVelocity(const b2Vec2& v)
{
    if (m_type == b2_staticBody)
    {
        return;
    }

    if (b2Dot(v,v) > 0.0f)
    {
        SetAwake(true);
    }

    m_linearVelocity = v;
}

inline b2Vec2 b2Body::GetLinearVelocity() const
{
    return m_linearVelocity;
}

inline void b2Body::SetAngularVelocity(float32 w)
{
    if (m_type == b2_staticBody)
    {
        return;
    }

    if (w * w > 0.0f)
    {
        SetAwake(true);
    }

    m_angularVelocity = w;
}

inline float32 b2Body::GetAngularVelocity() const
{
    return m_angularVelocity;
}

inline float32 b2Body::GetMass() const
{
    return m_mass;
}

inline float32 b2Body::GetInertia() const
{
    return m_I + m_mass * b2Dot(m_sweep.localCenter, m_sweep.localCenter);
}

inline void b2Body::GetMassData(b2MassData* data) const
{
    data->mass = m_mass;
    data->I = m_I + m_mass * b2Dot(m_sweep.localCenter, m_sweep.localCenter);
    data->center = m_sweep.localCenter;
}

inline b2Vec2 b2Body::GetWorldPoint(const b2Vec2& localPoint) const
{
    return b2Mul(m_xf, localPoint);
}

inline b2Vec2 b2Body::GetWorldVector(const b2Vec2& localVector) const
{
    return b2Mul(m_xf.q, localVector);
}

inline b2Vec2 b2Body::GetLocalPoint(const b2Vec2& worldPoint) const
{
    return b2MulT(m_xf, worldPoint);
}

inline b2Vec2 b2Body::GetLocalVector(const b2Vec2& worldVector) const
{
    return b2MulT(m_xf.q, worldVector);
}

inline b2Vec2 b2Body::GetLinearVelocityFromWorldPoint(const b2Vec2& worldPoint) const
{
    return m_linearVelocity + b2Cross(m_angularVelocity, worldPoint - m_sweep.c);
}

inline b2Vec2 b2Body::GetLinearVelocityFromLocalPoint(const b2Vec2& localPoint) const
{
    return GetLinearVelocityFromWorldPoint(GetWorldPoint(localPoint));
}

inline float32 b2Body::GetLinearDamping() const
{
    return m_linearDamping;
}

inline void b2Body::SetLinearDamping(float32 linearDamping)
{
    m_linearDamping = linearDamping;
}

inline float32 b2Body::GetAngularDamping() const
{
    return m_angularDamping;
}

inline void b2Body::SetAngularDamping(float32 angularDamping)
{
    m_angularDamping = angularDamping;
}

inline float32 b2Body::GetGravityScale() const
{
    return m_gravityScale;
}

inline void b2Body::SetGravityScale(float32 scale)
{
    m_gravityScale = scale;
}

inline void b2Body::SetBullet(bool flag)
{
    if (flag)
    {
        m_flags |= e_bulletFlag;
    }
    else
    {
        m_flags &= ~e_bulletFlag;
    }
}

inline bool b2Body::IsBullet() const
{
    return (m_flags & e_bulletFlag) == e_bulletFlag;
}

inline void b2Body::SetAwake(bool flag)
{
    if (flag)
    {
        if ((m_flags & e_awakeFlag) == 0)
        {
            m_flags |= e_awakeFlag;
            m_sleepTime = 0.0f;
        }
    }
    else
    {
        m_flags &= ~e_awakeFlag;
        m_sleepTime = 0.0f;
        m_linearVelocity.SetZero();
        m_angularVelocity = 0.0f;
        m_force.SetZero();
        m_torque = 0.0f;
    }
}

inline bool b2Body::IsAwake() const
{
    return (m_flags & e_awakeFlag) == e_awakeFlag;
}

inline bool b2Body::IsActive() const
{
    return (m_flags & e_activeFlag) == e_activeFlag;
}

inline void b2Body::SetFixedRotation(bool flag)
{
    if (flag)
    {
        m_flags |= e_fixedRotationFlag;
    }
    else
    {
        m_flags &= ~e_fixedRotationFlag;
    }

    ResetMassData();
}

inline bool b2Body::IsFixedRotation() const
{
    return (m_flags & e_fixedRotationFlag) == e_fixedRotationFlag;
}

inline void b2Body::SetSleepingAllowed(bool flag)
{
    if (flag)
    {
        m_flags |= e_autoSleepFlag;
    }
    else
    {
        m_flags &= ~e_autoSleepFlag;
        SetAwake(true);
    }
}

inline bool b2Body::IsSleepingAllowed() const
{
    return (m_flags & e_autoSleepFlag) == e_autoSleepFlag;
}

inline b2Fixture* b2Body::GetFixtureList()
{
    return m_fixtureList;
}

inline const b2Fixture* b2Body::GetFixtureList() const
{
    return m_fixtureList;
}

inline b2JointEdge* b2Body::GetJointList()
{
    return m_jointList;
}

inline const b2JointEdge* b2Body::GetJointList() const
{
    return m_jointList;
}

inline b2ContactEdge* b2Body::GetContactList()
{
    return m_contactList;
}

inline const b2ContactEdge* b2Body::GetContactList() const
{
    return m_contactList;
}

inline b2Body* b2Body::GetNext()
{
    return m_next;
}

inline const b2Body* b2Body::GetNext() const
{
    return m_next;
}

inline void b2Body::SetUserData(void* data)
{
    m_userData = data;
}

inline void* b2Body::GetUserData() const
{
    return m_userData;
}

inline void b2Body::ApplyForce(const b2Vec2& force, const b2Vec2& point)
{
    if (m_type != b2_dynamicBody)
    {
        return;
    }

    if (IsAwake() == false)
    {
        SetAwake(true);
    }

    m_force += force;
    m_torque += b2Cross(point - m_sweep.c, force);
}

inline void b2Body::ApplyForceToCenter(const b2Vec2& force)
{
    if (m_type != b2_dynamicBody)
    {
        return;
    }

    if (IsAwake() == false)
    {
        SetAwake(true);
    }

    m_force += force;
}

inline void b2Body::ApplyTorque(float32 torque)
{
    if (m_type != b2_dynamicBody)
    {
        return;
    }

    if (IsAwake() == false)
    {
        SetAwake(true);
    }

    m_torque += torque;
}

inline void b2Body::ApplyLinearImpulse(const b2Vec2& impulse, const b2Vec2& point)
{
    if (m_type != b2_dynamicBody)
    {
        return;
    }

    if (IsAwake() == false)
    {
        SetAwake(true);
    }
    m_linearVelocity += m_invMass * impulse;
    m_angularVelocity += m_invI * b2Cross(point - m_sweep.c, impulse);
}

inline void b2Body::ApplyAngularImpulse(float32 impulse)
{
    if (m_type != b2_dynamicBody)
    {
        return;
    }

    if (IsAwake() == false)
    {
        SetAwake(true);
    }
    m_angularVelocity += m_invI * impulse;
}

inline void b2Body::SynchronizeTransform()
{
    m_xf.q.Set(m_sweep.a);
    m_xf.p = m_sweep.c - b2Mul(m_xf.q, m_sweep.localCenter);
}

inline void b2Body::Advance(float32 alpha)
{
    // Advance to the new safe time. This doesn't sync the broad-phase.
    m_sweep.Advance(alpha);
    m_sweep.c = m_sweep.c0;
    m_sweep.a = m_sweep.a0;
    m_xf.q.Set(m_sweep.a);
    m_xf.p = m_sweep.c - b2Mul(m_xf.q, m_sweep.localCenter);
}

inline b2World* b2Body::GetWorld()
{
    return m_world;
}

inline const b2World* b2Body::GetWorld() const
{
    return m_world;
}

#endif