mirror of https://github.com/axmolengine/axmol.git
134 lines
4.0 KiB
C++
134 lines
4.0 KiB
C++
// MIT License
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// Copyright (c) 2019 Erin Catto
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// Permission is hereby granted, free of charge, to any person obtaining a copy
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// of this software and associated documentation files (the "Software"), to deal
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// in the Software without restriction, including without limitation the rights
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// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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// copies of the Software, and to permit persons to whom the Software is
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// furnished to do so, subject to the following conditions:
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// The above copyright notice and this permission notice shall be included in all
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// copies or substantial portions of the Software.
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// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
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// SOFTWARE.
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#ifndef B2_WELD_JOINT_H
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#define B2_WELD_JOINT_H
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#include "b2_api.h"
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#include "b2_joint.h"
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/// Weld joint definition. You need to specify local anchor points
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/// where they are attached and the relative body angle. The position
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/// of the anchor points is important for computing the reaction torque.
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struct B2_API b2WeldJointDef : public b2JointDef
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{
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b2WeldJointDef()
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{
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type = e_weldJoint;
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localAnchorA.Set(0.0f, 0.0f);
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localAnchorB.Set(0.0f, 0.0f);
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referenceAngle = 0.0f;
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stiffness = 0.0f;
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damping = 0.0f;
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}
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/// Initialize the bodies, anchors, reference angle, stiffness, and damping.
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/// @param bodyA the first body connected by this joint
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/// @param bodyB the second body connected by this joint
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/// @param anchor the point of connection in world coordinates
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void Initialize(b2Body* bodyA, b2Body* bodyB, const b2Vec2& anchor);
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/// The local anchor point relative to bodyA's origin.
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b2Vec2 localAnchorA;
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/// The local anchor point relative to bodyB's origin.
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b2Vec2 localAnchorB;
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/// The bodyB angle minus bodyA angle in the reference state (radians).
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float referenceAngle;
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/// The rotational stiffness in N*m
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/// Disable softness with a value of 0
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float stiffness;
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/// The rotational damping in N*m*s
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float damping;
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};
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/// A weld joint essentially glues two bodies together. A weld joint may
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/// distort somewhat because the island constraint solver is approximate.
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class B2_API b2WeldJoint : public b2Joint
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{
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public:
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b2Vec2 GetAnchorA() const override;
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b2Vec2 GetAnchorB() const override;
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b2Vec2 GetReactionForce(float inv_dt) const override;
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float GetReactionTorque(float inv_dt) const override;
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/// The local anchor point relative to bodyA's origin.
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const b2Vec2& GetLocalAnchorA() const { return m_localAnchorA; }
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/// The local anchor point relative to bodyB's origin.
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const b2Vec2& GetLocalAnchorB() const { return m_localAnchorB; }
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/// Get the reference angle.
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float GetReferenceAngle() const { return m_referenceAngle; }
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/// Set/get stiffness in N*m
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void SetStiffness(float hz) { m_stiffness = hz; }
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float GetStiffness() const { return m_stiffness; }
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/// Set/get damping in N*m*s
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void SetDamping(float damping) { m_damping = damping; }
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float GetDamping() const { return m_damping; }
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/// Dump to b2Log
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void Dump() override;
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protected:
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friend class b2Joint;
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b2WeldJoint(const b2WeldJointDef* def);
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void InitVelocityConstraints(const b2SolverData& data) override;
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void SolveVelocityConstraints(const b2SolverData& data) override;
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bool SolvePositionConstraints(const b2SolverData& data) override;
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float m_stiffness;
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float m_damping;
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float m_bias;
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// Solver shared
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b2Vec2 m_localAnchorA;
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b2Vec2 m_localAnchorB;
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float m_referenceAngle;
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float m_gamma;
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b2Vec3 m_impulse;
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// Solver temp
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int32 m_indexA;
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int32 m_indexB;
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b2Vec2 m_rA;
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b2Vec2 m_rB;
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b2Vec2 m_localCenterA;
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b2Vec2 m_localCenterB;
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float m_invMassA;
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float m_invMassB;
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float m_invIA;
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float m_invIB;
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b2Mat33 m_mass;
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};
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#endif
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