Bullet Collision Detection & Physics Library
btGjkConvexCast.cpp
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1 /*
2 Bullet Continuous Collision Detection and Physics Library
3 Copyright (c) 2003-2006 Erwin Coumans http://continuousphysics.com/Bullet/
4 
5 This software is provided 'as-is', without any express or implied warranty.
6 In no event will the authors be held liable for any damages 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 freely,
9 subject to the following restrictions:
10 
11 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.
12 2. Altered source versions must be plainly marked as such, and must not be misrepresented as being the original software.
13 3. This notice may not be removed or altered from any source distribution.
14 */
15 
16 #include "btGjkConvexCast.h"
18 #include "btGjkPairDetector.h"
19 #include "btPointCollector.h"
21 
22 #ifdef BT_USE_DOUBLE_PRECISION
23 #define MAX_ITERATIONS 64
24 #else
25 #define MAX_ITERATIONS 32
26 #endif
27 
29  : m_simplexSolver(simplexSolver),
30  m_convexA(convexA),
31  m_convexB(convexB)
32 {
33 }
34 
36  const btTransform& fromA,
37  const btTransform& toA,
38  const btTransform& fromB,
39  const btTransform& toB,
40  CastResult& result)
41 {
42  m_simplexSolver->reset();
43 
45  //assume no rotation/angular velocity, assert here?
46  btVector3 linVelA, linVelB;
47  linVelA = toA.getOrigin() - fromA.getOrigin();
48  linVelB = toB.getOrigin() - fromB.getOrigin();
49 
50  btScalar radius = btScalar(0.001);
51  btScalar lambda = btScalar(0.);
52  btVector3 v(1, 0, 0);
53 
54  int maxIter = MAX_ITERATIONS;
55 
56  btVector3 n;
57  n.setValue(btScalar(0.), btScalar(0.), btScalar(0.));
58  bool hasResult = false;
59  btVector3 c;
60  btVector3 r = (linVelA - linVelB);
61 
62  btScalar lastLambda = lambda;
63  //btScalar epsilon = btScalar(0.001);
64 
65  int numIter = 0;
66  //first solution, using GJK
67 
68  btTransform identityTrans;
69  identityTrans.setIdentity();
70 
71  // result.drawCoordSystem(sphereTr);
72 
73  btPointCollector pointCollector;
74 
75  btGjkPairDetector gjk(m_convexA, m_convexB, m_simplexSolver, 0); //m_penetrationDepthSolver);
77 
78  //we don't use margins during CCD
79  // gjk.setIgnoreMargin(true);
80 
81  input.m_transformA = fromA;
82  input.m_transformB = fromB;
83  gjk.getClosestPoints(input, pointCollector, 0);
84 
85  hasResult = pointCollector.m_hasResult;
86  c = pointCollector.m_pointInWorld;
87 
88  if (hasResult)
89  {
90  btScalar dist;
91  dist = pointCollector.m_distance;
92  n = pointCollector.m_normalOnBInWorld;
93 
94  //not close enough
95  while (dist > radius)
96  {
97  numIter++;
98  if (numIter > maxIter)
99  {
100  return false; //todo: report a failure
101  }
102  btScalar dLambda = btScalar(0.);
103 
104  btScalar projectedLinearVelocity = r.dot(n);
105 
106  dLambda = dist / (projectedLinearVelocity);
107 
108  lambda = lambda - dLambda;
109 
110  if (lambda > btScalar(1.))
111  return false;
112 
113  if (lambda < btScalar(0.))
114  return false;
115 
116  //todo: next check with relative epsilon
117  if (lambda <= lastLambda)
118  {
119  return false;
120  //n.setValue(0,0,0);
121  break;
122  }
123  lastLambda = lambda;
124 
125  //interpolate to next lambda
126  result.DebugDraw(lambda);
127  input.m_transformA.getOrigin().setInterpolate3(fromA.getOrigin(), toA.getOrigin(), lambda);
128  input.m_transformB.getOrigin().setInterpolate3(fromB.getOrigin(), toB.getOrigin(), lambda);
129 
130  gjk.getClosestPoints(input, pointCollector, 0);
131  if (pointCollector.m_hasResult)
132  {
133  if (pointCollector.m_distance < btScalar(0.))
134  {
135  result.m_fraction = lastLambda;
136  n = pointCollector.m_normalOnBInWorld;
137  result.m_normal = n;
138  result.m_hitPoint = pointCollector.m_pointInWorld;
139  return true;
140  }
141  c = pointCollector.m_pointInWorld;
142  n = pointCollector.m_normalOnBInWorld;
143  dist = pointCollector.m_distance;
144  }
145  else
146  {
147  //??
148  return false;
149  }
150  }
151 
152  //is n normalized?
153  //don't report time of impact for motion away from the contact normal (or causes minor penetration)
154  if (n.dot(r) >= -result.m_allowedPenetration)
155  return false;
156 
157  result.m_fraction = lambda;
158  result.m_normal = n;
159  result.m_hitPoint = c;
160  return true;
161  }
162 
163  return false;
164 }
MAX_ITERATIONS
#define MAX_ITERATIONS
Definition: btGjkConvexCast.cpp:25
btVector3::setValue
void setValue(const btScalar &_x, const btScalar &_y, const btScalar &_z)
Definition: btVector3.h:640
btScalar
float btScalar
The btScalar type abstracts floating point numbers, to easily switch between double and single floati...
Definition: btScalar.h:314
btGjkConvexCast::m_convexA
const btConvexShape * m_convexA
Definition: btGjkConvexCast.h:31
btGjkConvexCast::m_convexB
const btConvexShape * m_convexB
Definition: btGjkConvexCast.h:32
btPointCollector::m_distance
btScalar m_distance
Definition: btPointCollector.h:25
btGjkConvexCast::m_simplexSolver
btSimplexSolverInterface * m_simplexSolver
Definition: btGjkConvexCast.h:30
btVector3::dot
btScalar dot(const btVector3 &v) const
Return the dot product.
Definition: btVector3.h:229
btGjkConvexCast::calcTimeOfImpact
virtual bool calcTimeOfImpact(const btTransform &fromA, const btTransform &toA, const btTransform &fromB, const btTransform &toB, CastResult &result)
cast a convex against another convex object
Definition: btGjkConvexCast.cpp:35
btPointCollector.h
btGjkPairDetector.h
btTransformUtil.h
btVector3::setInterpolate3
void setInterpolate3(const btVector3 &v0, const btVector3 &v1, btScalar rt)
Definition: btVector3.h:492
btTransform::setIdentity
void setIdentity()
Set this transformation to the identity.
Definition: btTransform.h:166
btDiscreteCollisionDetectorInterface::ClosestPointInput::m_transformA
btTransform m_transformA
Definition: btDiscreteCollisionDetectorInterface.h:46
btConvexCast::CastResult
RayResult stores the closest result alternatively, add a callback method to decide about closest/all ...
Definition: btConvexCast.h:46
btDiscreteCollisionDetectorInterface::ClosestPointInput::m_transformB
btTransform m_transformB
Definition: btDiscreteCollisionDetectorInterface.h:47
btGjkPairDetector
btGjkPairDetector uses GJK to implement the btDiscreteCollisionDetectorInterface
Definition: btGjkPairDetector.h:27
btPointCollector::m_pointInWorld
btVector3 m_pointInWorld
Definition: btPointCollector.h:24
btTransform
The btTransform class supports rigid transforms with only translation and rotation and no scaling/she...
Definition: btTransform.h:28
btVector3
btVector3 can be used to represent 3D points and vectors.
Definition: btVector3.h:80
btSphereShape.h
btTransform::getOrigin
btVector3 & getOrigin()
Return the origin vector translation.
Definition: btTransform.h:113
btConvexShape
The btConvexShape is an abstract shape interface, implemented by all convex shapes such as btBoxShape...
Definition: btConvexShape.h:31
btConvexCast::CastResult::m_fraction
btScalar m_fraction
Definition: btConvexCast.h:72
btConvexCast::CastResult::m_hitPoint
btVector3 m_hitPoint
Definition: btConvexCast.h:71
btPointCollector::m_hasResult
bool m_hasResult
Definition: btPointCollector.h:27
btConvexCast::CastResult::m_normal
btVector3 m_normal
Definition: btConvexCast.h:70
btGjkConvexCast::btGjkConvexCast
btGjkConvexCast(const btConvexShape *convexA, const btConvexShape *convexB, btSimplexSolverInterface *simplexSolver)
Definition: btGjkConvexCast.cpp:28
btPointCollector
Definition: btPointCollector.h:21
btGjkPairDetector::getClosestPoints
virtual void getClosestPoints(const ClosestPointInput &input, Result &output, class btIDebugDraw *debugDraw, bool swapResults=false)
Definition: btGjkPairDetector.cpp:73
btConvexCast::CastResult::m_allowedPenetration
btScalar m_allowedPenetration
Definition: btConvexCast.h:74
btConvexCast::CastResult::DebugDraw
virtual void DebugDraw(btScalar fraction)
Definition: btConvexCast.h:50
btPointCollector::m_normalOnBInWorld
btVector3 m_normalOnBInWorld
Definition: btPointCollector.h:23
btSimplexSolverInterface
#define btSimplexSolverInterface
Definition: btSimplexSolverInterface.h:24
btGjkConvexCast.h
btDiscreteCollisionDetectorInterface::ClosestPointInput
Definition: btDiscreteCollisionDetectorInterface.h:39