Rename Box2D folder to box2d

src/libraries/box2d/b2_joint.h

@@ -0,0 +1,236 @@
+// 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_JOINT_H
+#define B2_JOINT_H
+
+#include "b2_math.h"
+
+class b2Body;
+class b2Draw;
+class b2Joint;
+struct b2SolverData;
+class b2BlockAllocator;
+
+enum b2JointType
+{
+	e_unknownJoint,
+	e_revoluteJoint,
+	e_prismaticJoint,
+	e_distanceJoint,
+	e_pulleyJoint,
+	e_mouseJoint,
+	e_gearJoint,
+	e_wheelJoint,
+    e_weldJoint,
+	e_frictionJoint,
+	e_ropeJoint,
+	e_motorJoint
+};
+
+struct b2Jacobian
+{
+	b2Vec2 linear;
+	float angularA;
+	float angularB;
+};
+
+/// A joint edge is used to connect bodies and joints together
+/// in a joint graph where each body is a node and each joint
+/// is an edge. A joint edge belongs to a doubly linked list
+/// maintained in each attached body. Each joint has two joint
+/// nodes, one for each attached body.
+struct b2JointEdge
+{
+	b2Body* other;			///< provides quick access to the other body attached.
+	b2Joint* joint;			///< the joint
+	b2JointEdge* prev;		///< the previous joint edge in the body's joint list
+	b2JointEdge* next;		///< the next joint edge in the body's joint list
+};
+
+/// Joint definitions are used to construct joints.
+struct b2JointDef
+{
+	b2JointDef()
+	{
+		type = e_unknownJoint;
+		userData = nullptr;
+		bodyA = nullptr;
+		bodyB = nullptr;
+		collideConnected = false;
+	}
+
+	/// The joint type is set automatically for concrete joint types.
+	b2JointType type;
+
+	/// Use this to attach application specific data to your joints.
+	void* userData;
+
+	/// The first attached body.
+	b2Body* bodyA;
+
+	/// The second attached body.
+	b2Body* bodyB;
+
+	/// Set this flag to true if the attached bodies should collide.
+	bool collideConnected;
+};
+
+/// Utility to compute linear stiffness values from frequency and damping ratio
+void b2LinearStiffness(float& stiffness, float& damping,
+	float frequencyHertz, float dampingRatio,
+	const b2Body* bodyA, const b2Body* bodyB);
+
+/// Utility to compute rotational stiffness values frequency and damping ratio
+void b2AngularStiffness(float& stiffness, float& damping,
+	float frequencyHertz, float dampingRatio,
+	const b2Body* bodyA, const b2Body* bodyB);
+
+/// The base joint class. Joints are used to constraint two bodies together in
+/// various fashions. Some joints also feature limits and motors.
+class b2Joint
+{
+public:
+
+	/// Get the type of the concrete joint.
+	b2JointType GetType() const;
+
+	/// Get the first body attached to this joint.
+	b2Body* GetBodyA();
+
+	/// Get the second body attached to this joint.
+	b2Body* GetBodyB();
+
+	/// Get the anchor point on bodyA in world coordinates.
+	virtual b2Vec2 GetAnchorA() const = 0;
+
+	/// Get the anchor point on bodyB in world coordinates.
+	virtual b2Vec2 GetAnchorB() const = 0;
+
+	/// Get the reaction force on bodyB at the joint anchor in Newtons.
+	virtual b2Vec2 GetReactionForce(float inv_dt) const = 0;
+
+	/// Get the reaction torque on bodyB in N*m.
+	virtual float GetReactionTorque(float inv_dt) const = 0;
+
+	/// Get the next joint the world joint list.
+	b2Joint* GetNext();
+	const b2Joint* GetNext() const;
+
+	/// Get the user data pointer.
+	void* GetUserData() const;
+
+	/// Set the user data pointer.
+	void SetUserData(void* data);
+
+	/// Short-cut function to determine if either body is enabled.
+	bool IsEnabled() const;
+
+	/// Get collide connected.
+	/// Note: modifying the collide connect flag won't work correctly because
+	/// the flag is only checked when fixture AABBs begin to overlap.
+	bool GetCollideConnected() const;
+
+	/// Dump this joint to the log file.
+	virtual void Dump() { b2Dump("// Dump is not supported for this joint type.\n"); }
+
+	/// Shift the origin for any points stored in world coordinates.
+	virtual void ShiftOrigin(const b2Vec2& newOrigin) { B2_NOT_USED(newOrigin);  }
+
+	/// Debug draw this joint
+	virtual void Draw(b2Draw* draw) const;
+
+protected:
+	friend class b2World;
+	friend class b2Body;
+	friend class b2Island;
+	friend class b2GearJoint;
+
+	static b2Joint* Create(const b2JointDef* def, b2BlockAllocator* allocator);
+	static void Destroy(b2Joint* joint, b2BlockAllocator* allocator);
+
+	b2Joint(const b2JointDef* def);
+	virtual ~b2Joint() {}
+
+	virtual void InitVelocityConstraints(const b2SolverData& data) = 0;
+	virtual void SolveVelocityConstraints(const b2SolverData& data) = 0;
+
+	// This returns true if the position errors are within tolerance.
+	virtual bool SolvePositionConstraints(const b2SolverData& data) = 0;
+
+	b2JointType m_type;
+	b2Joint* m_prev;
+	b2Joint* m_next;
+	b2JointEdge m_edgeA;
+	b2JointEdge m_edgeB;
+	b2Body* m_bodyA;
+	b2Body* m_bodyB;
+
+	int32 m_index;
+
+	bool m_islandFlag;
+	bool m_collideConnected;
+
+	void* m_userData;
+};
+
+inline b2JointType b2Joint::GetType() const
+{
+	return m_type;
+}
+
+inline b2Body* b2Joint::GetBodyA()
+{
+	return m_bodyA;
+}
+
+inline b2Body* b2Joint::GetBodyB()
+{
+	return m_bodyB;
+}
+
+inline b2Joint* b2Joint::GetNext()
+{
+	return m_next;
+}
+
+inline const b2Joint* b2Joint::GetNext() const
+{
+	return m_next;
+}
+
+inline void* b2Joint::GetUserData() const
+{
+	return m_userData;
+}
+
+inline void b2Joint::SetUserData(void* data)
+{
+	m_userData = data;
+}
+
+inline bool b2Joint::GetCollideConnected() const
+{
+	return m_collideConnected;
+}
+
+#endif