text: /*
  * Copyright (c) 2006-2009 Erin Catto http://www.gphysics.com
  *
  * 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_CONTACT_SOLVER_H
  #define B2_CONTACT_SOLVER_H
  
  #include "b2Math.h"
  #include "b2Collision.h"
  #include "b2Island.h"
  
  class b2Contact;
  class b2Body;
  class b2StackAllocator;
  
  struct b2ContactConstraintPoint
  {
  	b2Vec2 localPoint;
  	b2Vec2 rA;
  	b2Vec2 rB;
  	float32 normalImpulse;
  	float32 tangentImpulse;
  	float32 normalMass;
  	float32 tangentMass;
  	float32 velocityBias;
  };
  
  struct b2ContactConstraint
  {
  	b2ContactConstraintPoint points[b2_maxManifoldPoints];
  	b2Vec2 localNormal;
  	b2Vec2 localPoint;
  	b2Vec2 normal;
  	b2Mat22 normalMass;
  	b2Mat22 K;
  	b2Body* bodyA;
  	b2Body* bodyB;
  	b2Manifold::Type type;
  	float32 radius;
  	float32 friction;
  	int32 pointCount;
  	b2Manifold* manifold;
  };
  
  class b2ContactSolver
  {
  public:
  	b2ContactSolver(b2Contact** contacts, int32 contactCount,
  					b2StackAllocator* allocator, float32 impulseRatio);
  
  	~b2ContactSolver();
  
  	void WarmStart();
  	void SolveVelocityConstraints();
  	void StoreImpulses();
  
  	bool SolvePositionConstraints(float32 baumgarte);
  
  	b2StackAllocator* m_allocator;
  	b2ContactConstraint* m_constraints;
  	int m_constraintCount;
  };
  
  #endif
  