1 /*
2 * Copyright (c) 2006-2009 Erin Catto http://www.box2d.org
3 *
4 * This software is provided 'as-is', without any express or implied
5 * warranty.  In no event will the authors be held liable for any damages
6 * arising from the use of this software.
7 * Permission is granted to anyone to use this software for any purpose,
8 * including commercial applications, and to alter it and redistribute it
9 * freely, subject to the following restrictions:
10 * 1. The origin of this software must not be misrepresented; you must not
11 * claim that you wrote the original software. If you use this software
12 * in a product, an acknowledgment in the product documentation would be
13 * appreciated but is not required.
14 * 2. Altered source versions must be plainly marked as such, and must not be
15 * misrepresented as being the original software.
16 * 3. This notice may not be removed or altered from any source distribution.
17 */
18 
19 #ifndef B2_CONTACT_SOLVER_H
20 #define B2_CONTACT_SOLVER_H
21 
22 #include "../../Common/b2Math.h"
23 #include "../../Collision/b2Collision.h"
24 #include "../b2TimeStep.h"
25 
26 class b2Contact;
27 class b2Body;
28 class b2StackAllocator;
29 struct b2ContactPositionConstraint;
30 
31 struct b2VelocityConstraintPoint
32 {
33 	b2Vec2 rA;
34 	b2Vec2 rB;
35 	float32 normalImpulse;
36 	float32 tangentImpulse;
37 	float32 normalMass;
38 	float32 tangentMass;
39 	float32 velocityBias;
40 };
41 
42 struct b2ContactVelocityConstraint
43 {
44 	b2VelocityConstraintPoint points[b2_maxManifoldPoints];
45 	b2Vec2 normal;
46 	b2Mat22 normalMass;
47 	b2Mat22 K;
48 	int32 indexA;
49 	int32 indexB;
50 	float32 invMassA, invMassB;
51 	float32 invIA, invIB;
52 	float32 friction;
53 	float32 restitution;
54 	int32 pointCount;
55 	int32 contactIndex;
56 };
57 
58 struct b2ContactSolverDef
59 {
60 	b2TimeStep step;
61 	b2Contact** contacts;
62 	int32 count;
63 	b2Position* positions;
64 	b2Velocity* velocities;
65 	b2StackAllocator* allocator;
66 };
67 
68 class b2ContactSolver
69 {
70 public:
71 	b2ContactSolver(b2ContactSolverDef* def);
72 	~b2ContactSolver();
73 
74 	void InitializeVelocityConstraints();
75 
76 	void WarmStart();
77 	void SolveVelocityConstraints();
78 	void StoreImpulses();
79 
80 	bool SolvePositionConstraints();
81 	bool SolveTOIPositionConstraints(int32 toiIndexA, int32 toiIndexB);
82 
83 	b2TimeStep m_step;
84 	b2Position* m_positions;
85 	b2Velocity* m_velocities;
86 	b2StackAllocator* m_allocator;
87 	b2ContactPositionConstraint* m_positionConstraints;
88 	b2ContactVelocityConstraint* m_velocityConstraints;
89 	b2Contact** m_contacts;
90 	int m_count;
91 };
92 
93 #endif
94