Rename Box2D folder to box2d

src/libraries/box2d/b2_pulley_joint.h

@@ -0,0 +1,156 @@
+// 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_PULLEY_JOINT_H
+#define B2_PULLEY_JOINT_H
+
+#include "b2_joint.h"
+
+const float b2_minPulleyLength = 2.0f;
+
+/// Pulley joint definition. This requires two ground anchors,
+/// two dynamic body anchor points, and a pulley ratio.
+struct b2PulleyJointDef : public b2JointDef
+{
+	b2PulleyJointDef()
+	{
+		type = e_pulleyJoint;
+		groundAnchorA.Set(-1.0f, 1.0f);
+		groundAnchorB.Set(1.0f, 1.0f);
+		localAnchorA.Set(-1.0f, 0.0f);
+		localAnchorB.Set(1.0f, 0.0f);
+		lengthA = 0.0f;
+		lengthB = 0.0f;
+		ratio = 1.0f;
+		collideConnected = true;
+	}
+
+	/// Initialize the bodies, anchors, lengths, max lengths, and ratio using the world anchors.
+	void Initialize(b2Body* bodyA, b2Body* bodyB,
+					const b2Vec2& groundAnchorA, const b2Vec2& groundAnchorB,
+					const b2Vec2& anchorA, const b2Vec2& anchorB,
+					float ratio);
+
+	/// The first ground anchor in world coordinates. This point never moves.
+	b2Vec2 groundAnchorA;
+
+	/// The second ground anchor in world coordinates. This point never moves.
+	b2Vec2 groundAnchorB;
+
+	/// The local anchor point relative to bodyA's origin.
+	b2Vec2 localAnchorA;
+
+	/// The local anchor point relative to bodyB's origin.
+	b2Vec2 localAnchorB;
+
+	/// The a reference length for the segment attached to bodyA.
+	float lengthA;
+
+	/// The a reference length for the segment attached to bodyB.
+	float lengthB;
+
+	/// The pulley ratio, used to simulate a block-and-tackle.
+	float ratio;
+};
+
+/// The pulley joint is connected to two bodies and two fixed ground points.
+/// The pulley supports a ratio such that:
+/// length1 + ratio * length2 <= constant
+/// Yes, the force transmitted is scaled by the ratio.
+/// Warning: the pulley joint can get a bit squirrelly by itself. They often
+/// work better when combined with prismatic joints. You should also cover the
+/// the anchor points with static shapes to prevent one side from going to
+/// zero length.
+class b2PulleyJoint : 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;
+
+	/// Get the first ground anchor.
+	b2Vec2 GetGroundAnchorA() const;
+
+	/// Get the second ground anchor.
+	b2Vec2 GetGroundAnchorB() const;
+
+	/// Get the current length of the segment attached to bodyA.
+	float GetLengthA() const;
+
+	/// Get the current length of the segment attached to bodyB.
+	float GetLengthB() const;
+
+	/// Get the pulley ratio.
+	float GetRatio() const;
+
+	/// Get the current length of the segment attached to bodyA.
+	float GetCurrentLengthA() const;
+
+	/// Get the current length of the segment attached to bodyB.
+	float GetCurrentLengthB() const;
+
+	/// Dump joint to dmLog
+	void Dump() override;
+
+	/// Implement b2Joint::ShiftOrigin
+	void ShiftOrigin(const b2Vec2& newOrigin) override;
+
+protected:
+
+	friend class b2Joint;
+	b2PulleyJoint(const b2PulleyJointDef* data);
+
+	void InitVelocityConstraints(const b2SolverData& data) override;
+	void SolveVelocityConstraints(const b2SolverData& data) override;
+	bool SolvePositionConstraints(const b2SolverData& data) override;
+
+	b2Vec2 m_groundAnchorA;
+	b2Vec2 m_groundAnchorB;
+	float m_lengthA;
+	float m_lengthB;
+	
+	// Solver shared
+	b2Vec2 m_localAnchorA;
+	b2Vec2 m_localAnchorB;
+	float m_constant;
+	float m_ratio;
+	float m_impulse;
+
+	// Solver temp
+	int32 m_indexA;
+	int32 m_indexB;
+	b2Vec2 m_uA;
+	b2Vec2 m_uB;
+	b2Vec2 m_rA;
+	b2Vec2 m_rB;
+	b2Vec2 m_localCenterA;
+	b2Vec2 m_localCenterB;
+	float m_invMassA;
+	float m_invMassB;
+	float m_invIA;
+	float m_invIB;
+	float m_mass;
+};
+
+#endif