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b2Collision.h
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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
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14 * 2. Altered source versions must be plainly marked as such, and must not be
15 * misrepresented as being the original software.
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17 */
18 
19 #ifndef B2_COLLISION_H
20 #define B2_COLLISION_H
21 
22 #include <Box2D/Common/b2Math.h>
23 #include <climits>
24 
28 
29 class b2Shape;
30 class b2CircleShape;
31 class b2EdgeShape;
32 class b2PolygonShape;
33 
34 const uint8 b2_nullFeature = UCHAR_MAX;
35 
39 {
40  enum Type
41  {
42  e_vertex = 0,
43  e_face = 1
44  };
45 
46  uint8 indexA;
47  uint8 indexB;
48  uint8 typeA;
49  uint8 typeB;
50 };
51 
54 {
56  uint32 key;
57 };
58 
70 {
72  float32 normalImpulse;
73  float32 tangentImpulse;
75 };
76 
93 struct b2Manifold
94 {
95  enum Type
96  {
97  e_circles,
98  e_faceA,
99  e_faceB
100  };
101 
105  Type type;
106  int32 pointCount;
107 };
108 
111 {
116  void Initialize(const b2Manifold* manifold,
117  const b2Transform& xfA, float32 radiusA,
118  const b2Transform& xfB, float32 radiusB);
119 
122 };
123 
126 {
131 };
132 
135 void b2GetPointStates(b2PointState state1[b2_maxManifoldPoints], b2PointState state2[b2_maxManifoldPoints],
136  const b2Manifold* manifold1, const b2Manifold* manifold2);
137 
140 {
141  b2Vec2 v;
142  b2ContactID id;
143 };
144 
147 {
148  b2Vec2 p1, p2;
149  float32 maxFraction;
150 };
151 
155 {
156  b2Vec2 normal;
157  float32 fraction;
158 };
159 
161 struct b2AABB
162 {
164  bool IsValid() const;
165 
168  {
169  return 0.5f * (lowerBound + upperBound);
170  }
171 
174  {
175  return 0.5f * (upperBound - lowerBound);
176  }
177 
179  float32 GetPerimeter() const
180  {
181  float32 wx = upperBound.x - lowerBound.x;
182  float32 wy = upperBound.y - lowerBound.y;
183  return 2.0f * (wx + wy);
184  }
185 
187  void Combine(const b2AABB& aabb)
188  {
189  lowerBound = b2Min(lowerBound, aabb.lowerBound);
190  upperBound = b2Max(upperBound, aabb.upperBound);
191  }
192 
194  void Combine(const b2AABB& aabb1, const b2AABB& aabb2)
195  {
196  lowerBound = b2Min(aabb1.lowerBound, aabb2.lowerBound);
197  upperBound = b2Max(aabb1.upperBound, aabb2.upperBound);
198  }
199 
201  bool Contains(const b2AABB& aabb) const
202  {
203  bool result = true;
204  result = result && lowerBound.x <= aabb.lowerBound.x;
205  result = result && lowerBound.y <= aabb.lowerBound.y;
206  result = result && aabb.upperBound.x <= upperBound.x;
207  result = result && aabb.upperBound.y <= upperBound.y;
208  return result;
209  }
210 
211  bool RayCast(b2RayCastOutput* output, const b2RayCastInput& input) const;
212 
215 };
216 
218 void b2CollideCircles(b2Manifold* manifold,
219  const b2CircleShape* circleA, const b2Transform& xfA,
220  const b2CircleShape* circleB, const b2Transform& xfB);
221 
224  const b2PolygonShape* polygonA, const b2Transform& xfA,
225  const b2CircleShape* circleB, const b2Transform& xfB);
226 
228 void b2CollidePolygons(b2Manifold* manifold,
229  const b2PolygonShape* polygonA, const b2Transform& xfA,
230  const b2PolygonShape* polygonB, const b2Transform& xfB);
231 
233 void b2CollideEdgeAndCircle(b2Manifold* manifold,
234  const b2EdgeShape* polygonA, const b2Transform& xfA,
235  const b2CircleShape* circleB, const b2Transform& xfB);
236 
238 void b2CollideEdgeAndPolygon(b2Manifold* manifold,
239  const b2EdgeShape* edgeA, const b2Transform& xfA,
240  const b2PolygonShape* circleB, const b2Transform& xfB);
241 
243 int32 b2ClipSegmentToLine(b2ClipVertex vOut[2], const b2ClipVertex vIn[2],
244  const b2Vec2& normal, float32 offset, int32 vertexIndexA);
245 
247 bool b2TestOverlap( const b2Shape* shapeA, int32 indexA,
248  const b2Shape* shapeB, int32 indexB,
249  const b2Transform& xfA, const b2Transform& xfB);
250 
251 // ---------------- Inline Functions ------------------------------------------
252 
253 inline bool b2AABB::IsValid() const
254 {
256  bool valid = d.x >= 0.0f && d.y >= 0.0f;
257  valid = valid && lowerBound.IsValid() && upperBound.IsValid();
258  return valid;
259 }
260 
261 inline bool b2TestOverlap(const b2AABB& a, const b2AABB& b)
262 {
263  b2Vec2 d1, d2;
264  d1 = b.lowerBound - a.upperBound;
265  d2 = a.lowerBound - b.upperBound;
266 
267  if (d1.x > 0.0f || d1.y > 0.0f)
268  return false;
269 
270  if (d2.x > 0.0f || d2.y > 0.0f)
271  return false;
272 
273  return true;
274 }
275 
276 #endif
Definition: b2Math.h:361
b2Vec2 GetExtents() const
Get the extents of the AABB (half-widths).
Definition: b2Collision.h:173
A circle shape.
Definition: b2CircleShape.h:26
point was added in the update
Definition: b2Collision.h:128
b2Vec2 GetCenter() const
Get the center of the AABB.
Definition: b2Collision.h:167
b2Vec2 lowerBound
the lower vertex
Definition: b2Collision.h:213
bool IsValid() const
Does this vector contain finite coordinates?
Definition: b2Math.h:140
This is used to compute the current state of a contact manifold.
Definition: b2Collision.h:110
bool Contains(const b2AABB &aabb) const
Does this aabb contain the provided AABB.
Definition: b2Collision.h:201
uint8 typeA
The feature type on shapeA.
Definition: b2Collision.h:48
void Initialize(const b2Manifold *manifold, const b2Transform &xfA, float32 radiusA, const b2Transform &xfB, float32 radiusB)
Definition: b2Collision.cpp:22
void b2CollideEdgeAndPolygon(b2Manifold *manifold, const b2EdgeShape *edgeA, const b2Transform &xfA, const b2PolygonShape *circleB, const b2Transform &xfB)
Compute the collision manifold between an edge and a circle.
Definition: b2CollideEdge.cpp:692
Definition: b2Shape.h:43
Used for computing contact manifolds.
Definition: b2Collision.h:139
point does not exist
Definition: b2Collision.h:127
int32 b2ClipSegmentToLine(b2ClipVertex vOut[2], const b2ClipVertex vIn[2], const b2Vec2 &normal, float32 offset, int32 vertexIndexA)
Clipping for contact manifolds.
Definition: b2Collision.cpp:198
Definition: b2PolygonShape.h:29
Definition: b2Collision.h:154
float32 normalImpulse
the non-penetration impulse
Definition: b2Collision.h:72
Contact ids to facilitate warm starting.
Definition: b2Collision.h:53
Definition: b2Collision.h:38
point was removed in the update
Definition: b2Collision.h:130
void b2CollideCircles(b2Manifold *manifold, const b2CircleShape *circleA, const b2Transform &xfA, const b2CircleShape *circleB, const b2Transform &xfB)
Compute the collision manifold between two circles.
Definition: b2CollideCircle.cpp:23
b2Vec2 localPoint
usage depends on manifold type
Definition: b2Collision.h:71
b2ManifoldPoint points[b2_maxManifoldPoints]
the points of contact
Definition: b2Collision.h:102
b2Vec2 upperBound
the upper vertex
Definition: b2Collision.h:214
b2Vec2 localPoint
usage depends on manifold type
Definition: b2Collision.h:104
bool IsValid() const
Verify that the bounds are sorted.
Definition: b2Collision.h:253
float32 tangentImpulse
the friction impulse
Definition: b2Collision.h:73
An axis aligned bounding box.
Definition: b2Collision.h:161
b2Vec2 points[b2_maxManifoldPoints]
world contact point (point of intersection)
Definition: b2Collision.h:121
bool b2TestOverlap(const b2Shape *shapeA, int32 indexA, const b2Shape *shapeB, int32 indexB, const b2Transform &xfA, const b2Transform &xfB)
Determine if two generic shapes overlap.
Definition: b2Collision.cpp:230
point persisted across the update
Definition: b2Collision.h:129
uint8 typeB
The feature type on shapeB.
Definition: b2Collision.h:49
void b2CollidePolygonAndCircle(b2Manifold *manifold, const b2PolygonShape *polygonA, const b2Transform &xfA, const b2CircleShape *circleB, const b2Transform &xfB)
Compute the collision manifold between a polygon and a circle.
Definition: b2CollideCircle.cpp:51
Ray-cast input data. The ray extends from p1 to p1 + maxFraction * (p2 - p1).
Definition: b2Collision.h:146
Definition: b2EdgeShape.h:28
void b2CollidePolygons(b2Manifold *manifold, const b2PolygonShape *polygonA, const b2Transform &xfA, const b2PolygonShape *polygonB, const b2Transform &xfB)
Compute the collision manifold between two polygons.
Definition: b2CollidePolygon.cpp:193
uint8 indexA
Feature index on shapeA.
Definition: b2Collision.h:46
uint32 key
Used to quickly compare contact ids.
Definition: b2Collision.h:56
float32 GetPerimeter() const
Get the perimeter length.
Definition: b2Collision.h:179
Definition: b2Collision.h:93
b2PointState
This is used for determining the state of contact points.
Definition: b2Collision.h:125
void b2CollideEdgeAndCircle(b2Manifold *manifold, const b2EdgeShape *polygonA, const b2Transform &xfA, const b2CircleShape *circleB, const b2Transform &xfB)
Compute the collision manifold between an edge and a circle.
Definition: b2CollideEdge.cpp:27
int32 pointCount
the number of manifold points
Definition: b2Collision.h:106
void Combine(const b2AABB &aabb)
Combine an AABB into this one.
Definition: b2Collision.h:187
A 2D column vector.
Definition: b2Math.h:64
uint8 indexB
Feature index on shapeB.
Definition: b2Collision.h:47
#define b2_maxManifoldPoints
Definition: b2Settings.h:56
Definition: b2Collision.h:69
b2Vec2 normal
world vector pointing from A to B
Definition: b2Collision.h:120
void b2GetPointStates(b2PointState state1[b2_maxManifoldPoints], b2PointState state2[b2_maxManifoldPoints], const b2Manifold *manifold1, const b2Manifold *manifold2)
Definition: b2Collision.cpp:85
void Combine(const b2AABB &aabb1, const b2AABB &aabb2)
Combine two AABBs into this one.
Definition: b2Collision.h:194
b2Vec2 localNormal
not use for Type::e_points
Definition: b2Collision.h:103
b2ContactID id
uniquely identifies a contact point between two shapes
Definition: b2Collision.h:74