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