116 lines
1.9 KiB
C++
116 lines
1.9 KiB
C++
/*
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* Copyright (c) 2011 Erin Catto http://www.box2d.org
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*
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* This software is provided 'as-is', without any express or implied
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* warranty. In no event will the authors be held liable for any damages
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* arising from the use of this software.
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* Permission is granted to anyone to use this software for any purpose,
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* including commercial applications, and to alter it and redistribute it
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* freely, subject to the following restrictions:
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* 1. The origin of this software must not be misrepresented; you must not
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* claim that you wrote the original software. If you use this software
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* in a product, an acknowledgment in the product documentation would be
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* appreciated but is not required.
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* 2. Altered source versions must be plainly marked as such, and must not be
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* misrepresented as being the original software.
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* 3. This notice may not be removed or altered from any source distribution.
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*/
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#ifndef B2_ROPE_H
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#define B2_ROPE_H
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#include "Box2D/Common/b2Math.h"
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class b2Draw;
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///
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struct b2RopeDef
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{
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b2RopeDef()
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{
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vertices = nullptr;
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count = 0;
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masses = nullptr;
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gravity.SetZero();
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damping = 0.1f;
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k2 = 0.9f;
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k3 = 0.1f;
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}
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///
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b2Vec2* vertices;
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///
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int32 count;
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///
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float32* masses;
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///
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b2Vec2 gravity;
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///
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float32 damping;
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/// Stretching stiffness
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float32 k2;
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/// Bending stiffness. Values above 0.5 can make the simulation blow up.
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float32 k3;
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};
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///
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class b2Rope
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{
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public:
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b2Rope();
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~b2Rope();
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///
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void Initialize(const b2RopeDef* def);
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///
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void Step(float32 timeStep, int32 iterations);
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///
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int32 GetVertexCount() const
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{
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return m_count;
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}
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///
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const b2Vec2* GetVertices() const
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{
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return m_ps;
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}
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///
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void Draw(b2Draw* draw) const;
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///
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void SetAngle(float32 angle);
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private:
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void SolveC2();
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void SolveC3();
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int32 m_count;
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b2Vec2* m_ps;
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b2Vec2* m_p0s;
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b2Vec2* m_vs;
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float32* m_ims;
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float32* m_Ls;
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float32* m_as;
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b2Vec2 m_gravity;
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float32 m_damping;
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float32 m_k2;
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float32 m_k3;
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};
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#endif
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