b2_body.h

// MIT License
 
// Copyright (c) 2019 Erin Catto
 
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
 
// The above copyright notice and this permission notice shall be included in all
// copies or substantial portions of the Software.
 
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
// SOFTWARE.
 
#ifndef B2_BODY_H
#define B2_BODY_H
 
#include "b2_api.h"
#include "b2_math.h"
#include "b2_shape.h"
 
class b2Fixture;
class b2Joint;
class b2Contact;
class b2Controller;
class b2World;
struct b2FixtureDef;
struct b2JointEdge;
struct b2ContactEdge;
 
enum b2BodyType
{
    b2_staticBody = 0,
    b2_kinematicBody,
    b2_dynamicBody
};
 
struct B2_API b2BodyDef
{
    b2BodyDef()
    {
        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;
        enabled = true;
        gravityScale = 1.0f;
    }
 
    b2BodyType type;
 
    b2Vec2 position;
 
    float angle;
 
    b2Vec2 linearVelocity;
 
    float angularVelocity;
 
    float linearDamping;
 
    float angularDamping;
 
    bool allowSleep;
 
    bool awake;
 
    bool fixedRotation;
 
    bool bullet;
 
    bool enabled;
 
    b2BodyUserData userData;
 
    float gravityScale;
};
 
class B2_API b2Body
{
public:
    b2Fixture* CreateFixture(const b2FixtureDef* def);
 
    b2Fixture* CreateFixture(const b2Shape* shape, float density);
 
    void DestroyFixture(b2Fixture* fixture);
 
    void SetTransform(const b2Vec2& position, float angle);
 
    const b2Transform& GetTransform() const;
 
    const b2Vec2& GetPosition() const;
 
    float GetAngle() const;
 
    const b2Vec2& GetWorldCenter() const;
 
    const b2Vec2& GetLocalCenter() const;
 
    void SetLinearVelocity(const b2Vec2& v);
 
    const b2Vec2& GetLinearVelocity() const;
 
    void SetAngularVelocity(float omega);
 
    float GetAngularVelocity() const;
 
    void ApplyForce(const b2Vec2& force, const b2Vec2& point, bool wake);
 
    void ApplyForceToCenter(const b2Vec2& force, bool wake);
 
    void ApplyTorque(float torque, bool wake);
 
    void ApplyLinearImpulse(const b2Vec2& impulse, const b2Vec2& point, bool wake);
 
    void ApplyLinearImpulseToCenter(const b2Vec2& impulse, bool wake);
 
    void ApplyAngularImpulse(float impulse, bool wake);
 
    float GetMass() const;
 
    float GetInertia() const;
 
    b2MassData GetMassData() const;
 
    void SetMassData(const b2MassData* data);
 
    void ResetMassData();
 
    b2Vec2 GetWorldPoint(const b2Vec2& localPoint) const;
 
    b2Vec2 GetWorldVector(const b2Vec2& localVector) const;
 
    b2Vec2 GetLocalPoint(const b2Vec2& worldPoint) const;
 
    b2Vec2 GetLocalVector(const b2Vec2& worldVector) const;
 
    b2Vec2 GetLinearVelocityFromWorldPoint(const b2Vec2& worldPoint) const;
 
    b2Vec2 GetLinearVelocityFromLocalPoint(const b2Vec2& localPoint) const;
 
    float GetLinearDamping() const;
 
    void SetLinearDamping(float linearDamping);
 
    float GetAngularDamping() const;
 
    void SetAngularDamping(float angularDamping);
 
    float GetGravityScale() const;
 
    void SetGravityScale(float scale);
 
    void SetType(b2BodyType type);
 
    b2BodyType GetType() const;
 
    void SetBullet(bool flag);
 
    bool IsBullet() const;
 
    void SetSleepingAllowed(bool flag);
 
    bool IsSleepingAllowed() const;
 
    void SetAwake(bool flag);
 
    bool IsAwake() const;
 
    void SetEnabled(bool flag);
 
    bool IsEnabled() const;
 
    void SetFixedRotation(bool flag);
 
    bool IsFixedRotation() const;
 
    b2Fixture* GetFixtureList();
    const b2Fixture* GetFixtureList() const;
 
    b2JointEdge* GetJointList();
    const b2JointEdge* GetJointList() const;
 
    b2ContactEdge* GetContactList();
    const b2ContactEdge* GetContactList() const;
 
    b2Body* GetNext();
    const b2Body* GetNext() const;
 
    b2BodyUserData& GetUserData();
    const b2BodyUserData& GetUserData() const;
 
    b2World* GetWorld();
    const b2World* GetWorld() const;
 
    void Dump();
 
private:
 
    friend class b2World;
    friend class b2Island;
    friend class b2ContactManager;
    friend class b2ContactSolver;
    friend class b2Contact;
 
    friend class b2DistanceJoint;
    friend class b2FrictionJoint;
    friend class b2GearJoint;
    friend class b2MotorJoint;
    friend class b2MouseJoint;
    friend class b2PrismaticJoint;
    friend class b2PulleyJoint;
    friend class b2RevoluteJoint;
    friend class b2WeldJoint;
    friend class b2WheelJoint;
 
    // m_flags
    enum
    {
        e_islandFlag        = 0x0001,
        e_awakeFlag         = 0x0002,
        e_autoSleepFlag     = 0x0004,
        e_bulletFlag        = 0x0008,
        e_fixedRotationFlag = 0x0010,
        e_enabledFlag       = 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(float 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;
    float m_angularVelocity;
 
    b2Vec2 m_force;
    float m_torque;
 
    b2World* m_world;
    b2Body* m_prev;
    b2Body* m_next;
 
    b2Fixture* m_fixtureList;
    int32 m_fixtureCount;
 
    b2JointEdge* m_jointList;
    b2ContactEdge* m_contactList;
 
    float m_mass, m_invMass;
 
    // Rotational inertia about the center of mass.
    float m_I, m_invI;
 
    float m_linearDamping;
    float m_angularDamping;
    float m_gravityScale;
 
    float m_sleepTime;
 
    b2BodyUserData 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 float 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 const b2Vec2& b2Body::GetLinearVelocity() const
{
    return m_linearVelocity;
}
 
inline void b2Body::SetAngularVelocity(float w)
{
    if (m_type == b2_staticBody)
    {
        return;
    }
 
    if (w * w > 0.0f)
    {
        SetAwake(true);
    }
 
    m_angularVelocity = w;
}
 
inline float b2Body::GetAngularVelocity() const
{
    return m_angularVelocity;
}
 
inline float b2Body::GetMass() const
{
    return m_mass;
}
 
inline float b2Body::GetInertia() const
{
    return m_I + m_mass * b2Dot(m_sweep.localCenter, m_sweep.localCenter);
}
 
inline b2MassData b2Body::GetMassData() const
{
    b2MassData data;
    data.mass = m_mass;
    data.I = m_I + m_mass * b2Dot(m_sweep.localCenter, m_sweep.localCenter);
    data.center = m_sweep.localCenter;
    return data;
}
 
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 float b2Body::GetLinearDamping() const
{
    return m_linearDamping;
}
 
inline void b2Body::SetLinearDamping(float linearDamping)
{
    m_linearDamping = linearDamping;
}
 
inline float b2Body::GetAngularDamping() const
{
    return m_angularDamping;
}
 
inline void b2Body::SetAngularDamping(float angularDamping)
{
    m_angularDamping = angularDamping;
}
 
inline float b2Body::GetGravityScale() const
{
    return m_gravityScale;
}
 
inline void b2Body::SetGravityScale(float 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 (m_type == b2_staticBody)
    {
        return;
    }
 
    if (flag)
    {
        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::IsEnabled() const
{
    return (m_flags & e_enabledFlag) == e_enabledFlag;
}
 
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 b2BodyUserData& b2Body::GetUserData()
{
    return m_userData;
}
 
inline const b2BodyUserData& b2Body::GetUserData() const
{
    return m_userData;
}
 
inline void b2Body::ApplyForce(const b2Vec2& force, const b2Vec2& point, bool wake)
{
    if (m_type != b2_dynamicBody)
    {
        return;
    }
 
    if (wake && (m_flags & e_awakeFlag) == 0)
    {
        SetAwake(true);
    }
 
    // Don't accumulate a force if the body is sleeping.
    if (m_flags & e_awakeFlag)
    {
        m_force += force;
        m_torque += b2Cross(point - m_sweep.c, force);
    }
}
 
inline void b2Body::ApplyForceToCenter(const b2Vec2& force, bool wake)
{
    if (m_type != b2_dynamicBody)
    {
        return;
    }
 
    if (wake && (m_flags & e_awakeFlag) == 0)
    {
        SetAwake(true);
    }
 
    // Don't accumulate a force if the body is sleeping
    if (m_flags & e_awakeFlag)
    {
        m_force += force;
    }
}
 
inline void b2Body::ApplyTorque(float torque, bool wake)
{
    if (m_type != b2_dynamicBody)
    {
        return;
    }
 
    if (wake && (m_flags & e_awakeFlag) == 0)
    {
        SetAwake(true);
    }
 
    // Don't accumulate a force if the body is sleeping
    if (m_flags & e_awakeFlag)
    {
        m_torque += torque;
    }
}
 
inline void b2Body::ApplyLinearImpulse(const b2Vec2& impulse, const b2Vec2& point, bool wake)
{
    if (m_type != b2_dynamicBody)
    {
        return;
    }
 
    if (wake && (m_flags & e_awakeFlag) == 0)
    {
        SetAwake(true);
    }
 
    // Don't accumulate velocity if the body is sleeping
    if (m_flags & e_awakeFlag)
    {
        m_linearVelocity += m_invMass * impulse;
        m_angularVelocity += m_invI * b2Cross(point - m_sweep.c, impulse);
    }
}
 
inline void b2Body::ApplyLinearImpulseToCenter(const b2Vec2& impulse, bool wake)
{
    if (m_type != b2_dynamicBody)
    {
        return;
    }
 
    if (wake && (m_flags & e_awakeFlag) == 0)
    {
        SetAwake(true);
    }
 
    // Don't accumulate velocity if the body is sleeping
    if (m_flags & e_awakeFlag)
    {
        m_linearVelocity += m_invMass * impulse;
    }
}
 
inline void b2Body::ApplyAngularImpulse(float impulse, bool wake)
{
    if (m_type != b2_dynamicBody)
    {
        return;
    }
 
    if (wake && (m_flags & e_awakeFlag) == 0)
    {
        SetAwake(true);
    }
 
    // Don't accumulate velocity if the body is sleeping
    if (m_flags & e_awakeFlag)
    {
        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(float 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