b2_mouse_joint.h

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// 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_MOUSE_JOINT_H
#define B2_MOUSE_JOINT_H

#include "b2_api.h"
#include "b2_joint.h"

struct B2_API b2MouseJointDef : public b2JointDef
{
        b2MouseJointDef()
        {
                type = e_mouseJoint;
                target.Set(0.0f, 0.0f);
                maxForce = 0.0f;
                stiffness = 0.0f;
                damping = 0.0f;
        }

        b2Vec2 target;

        float maxForce;

        float stiffness;

        float damping;
};

class B2_API b2MouseJoint : public b2Joint
{
public:

        b2Vec2 GetAnchorA() const override;

        b2Vec2 GetAnchorB() const override;

        b2Vec2 GetReactionForce(float inv_dt) const override;

        float GetReactionTorque(float inv_dt) const override;

        void SetTarget(const b2Vec2& target);
        const b2Vec2& GetTarget() const;

        void SetMaxForce(float force);
        float GetMaxForce() const;

        void SetStiffness(float stiffness) { m_stiffness = stiffness; }
        float GetStiffness() const { return m_stiffness; }

        void SetDamping(float damping) { m_damping = damping; }
        float GetDamping() const { return m_damping; }

        void Dump() override { b2Log("Mouse joint dumping is not supported.\n"); }

        void ShiftOrigin(const b2Vec2& newOrigin) override;

protected:
        friend class b2Joint;

        b2MouseJoint(const b2MouseJointDef* def);

        void InitVelocityConstraints(const b2SolverData& data) override;
        void SolveVelocityConstraints(const b2SolverData& data) override;
        bool SolvePositionConstraints(const b2SolverData& data) override;

        b2Vec2 m_localAnchorB;
        b2Vec2 m_targetA;
        float m_stiffness;
        float m_damping;
        float m_beta;

        // Solver shared
        b2Vec2 m_impulse;
        float m_maxForce;
        float m_gamma;

        // Solver temp
        int32 m_indexA;
        int32 m_indexB;
        b2Vec2 m_rB;
        b2Vec2 m_localCenterB;
        float m_invMassB;
        float m_invIB;
        b2Mat22 m_mass;
        b2Vec2 m_C;
};

#endif