Rename Box2D folder to box2d

src/libraries/box2d/b2_weld_joint.h

@@ -0,0 +1,132 @@
+// 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_WELD_JOINT_H
+#define B2_WELD_JOINT_H
+
+#include "b2_joint.h"
+
+/// Weld joint definition. You need to specify local anchor points
+/// where they are attached and the relative body angle. The position
+/// of the anchor points is important for computing the reaction torque.
+struct b2WeldJointDef : public b2JointDef
+{
+	b2WeldJointDef()
+	{
+		type = e_weldJoint;
+		localAnchorA.Set(0.0f, 0.0f);
+		localAnchorB.Set(0.0f, 0.0f);
+		referenceAngle = 0.0f;
+		stiffness = 0.0f;
+		damping = 0.0f;
+	}
+
+	/// Initialize the bodies, anchors, reference angle, stiffness, and damping.
+	/// @param bodyA the first body connected by this joint
+	/// @param bodyB the second body connected by this joint
+	/// @param anchor the point of connection in world coordinates
+	void Initialize(b2Body* bodyA, b2Body* bodyB, const b2Vec2& anchor);
+
+	/// The local anchor point relative to bodyA's origin.
+	b2Vec2 localAnchorA;
+
+	/// The local anchor point relative to bodyB's origin.
+	b2Vec2 localAnchorB;
+
+	/// The bodyB angle minus bodyA angle in the reference state (radians).
+	float referenceAngle;
+	
+	/// The rotational stiffness in N*m
+	/// Disable softness with a value of 0
+	float stiffness;
+
+	/// The rotational damping in N*m*s
+	float damping;
+};
+
+/// A weld joint essentially glues two bodies together. A weld joint may
+/// distort somewhat because the island constraint solver is approximate.
+class b2WeldJoint : 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;
+
+	/// The local anchor point relative to bodyA's origin.
+	const b2Vec2& GetLocalAnchorA() const { return m_localAnchorA; }
+
+	/// The local anchor point relative to bodyB's origin.
+	const b2Vec2& GetLocalAnchorB() const  { return m_localAnchorB; }
+
+	/// Get the reference angle.
+	float GetReferenceAngle() const { return m_referenceAngle; }
+
+	/// Set/get stiffness in N*m
+	void SetStiffness(float hz) { m_stiffness = hz; }
+	float GetStiffness() const { return m_stiffness; }
+
+	/// Set/get damping in N*m*s
+	void SetDamping(float damping) { m_damping = damping; }
+	float GetDamping() const { return m_damping; }
+
+	/// Dump to b2Log
+	void Dump() override;
+
+protected:
+
+	friend class b2Joint;
+
+	b2WeldJoint(const b2WeldJointDef* def);
+
+	void InitVelocityConstraints(const b2SolverData& data) override;
+	void SolveVelocityConstraints(const b2SolverData& data) override;
+	bool SolvePositionConstraints(const b2SolverData& data) override;
+
+	float m_stiffness;
+	float m_damping;
+	float m_bias;
+
+	// Solver shared
+	b2Vec2 m_localAnchorA;
+	b2Vec2 m_localAnchorB;
+	float m_referenceAngle;
+	float m_gamma;
+	b2Vec3 m_impulse;
+
+	// Solver temp
+	int32 m_indexA;
+	int32 m_indexB;
+	b2Vec2 m_rA;
+	b2Vec2 m_rB;
+	b2Vec2 m_localCenterA;
+	b2Vec2 m_localCenterB;
+	float m_invMassA;
+	float m_invMassB;
+	float m_invIA;
+	float m_invIB;
+	b2Mat33 m_mass;
+};
+
+#endif