Bullet Collision Detection & Physics Library: btGjkConvexCast.cpp Source File

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btGjkConvexCast.cpp
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1/*
2Bullet Continuous Collision Detection and Physics Library
3Copyright (c) 2003-2006 Erwin Coumans https://bulletphysics.org
4
5This software is provided 'as-is', without any express or implied warranty.
6In no event will the authors be held liable for any damages arising from the use of this software.
7Permission is granted to anyone to use this software for any purpose,
8including commercial applications, and to alter it and redistribute it freely,
9subject to the following restrictions:
10
111. 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.
122. Altered source versions must be plainly marked as such, and must not be misrepresented as being the original software.
133. This notice may not be removed or altered from any source distribution.
14*/
15
16#include "btGjkConvexCast.h"
17#include "BulletCollision/CollisionShapes/btSphereShape.h"
18#include "btGjkPairDetector.h"
19#include "btPointCollector.h"
20#include "LinearMath/btTransformUtil.h"
21
22#ifdef BT_USE_DOUBLE_PRECISION
23#define MAX_ITERATIONS 64
24#else
25#define MAX_ITERATIONS 32
26#endif
27
28btGjkConvexCast::btGjkConvexCast(const btConvexShape* convexA, const btConvexShape* convexB, btSimplexSolverInterface* simplexSolver)
29 : m_simplexSolver(simplexSolver),
30 m_convexA(convexA),
31 m_convexB(convexB)
32{
33}
34
35 bool btGjkConvexCast::calcTimeOfImpact(
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);
76 btGjkPairDetector::ClosestPointInput input;
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
This maximum should not be necessary.
Definition: btContinuousConvexCollision.cpp:46
btGjkConvexCast.h
btGjkPairDetector.h
btPointCollector.h
btScalar
float btScalar
The btScalar type abstracts floating point numbers, to easily switch between double and single floati...
Definition: btScalar.h:314
btSimplexSolverInterface
#define btSimplexSolverInterface
Definition: btSimplexSolverInterface.h:24
btSphereShape.h
btTransformUtil.h
btConvexShape
The btConvexShape is an abstract shape interface, implemented by all convex shapes such as btBoxShape...
Definition: btConvexShape.h:33
btGjkConvexCast::m_convexB
const btConvexShape * m_convexB
Definition: btGjkConvexCast.h:32
btGjkConvexCast::m_simplexSolver
btSimplexSolverInterface * m_simplexSolver
Definition: btGjkConvexCast.h:30
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
btGjkConvexCast::m_convexA
const btConvexShape * m_convexA
Definition: btGjkConvexCast.h:31
btGjkConvexCast::btGjkConvexCast
btGjkConvexCast(const btConvexShape *convexA, const btConvexShape *convexB, btSimplexSolverInterface *simplexSolver)
Definition: btGjkConvexCast.cpp:28
btGjkPairDetector
btGjkPairDetector uses GJK to implement the btDiscreteCollisionDetectorInterface
Definition: btGjkPairDetector.h:28
btGjkPairDetector::getClosestPoints
virtual void getClosestPoints(const ClosestPointInput &input, Result &output, class btIDebugDraw *debugDraw, bool swapResults=false)
Definition: btGjkPairDetector.cpp:73
btTransform
The btTransform class supports rigid transforms with only translation and rotation and no scaling/she...
Definition: btTransform.h:30
btTransform::setIdentity
void setIdentity()
Set this transformation to the identity.
Definition: btTransform.h:167
btTransform::getOrigin
btVector3 & getOrigin()
Return the origin vector translation.
Definition: btTransform.h:114
btVector3
btVector3 can be used to represent 3D points and vectors.
Definition: btVector3.h:82
btVector3::setInterpolate3
void setInterpolate3(const btVector3 &v0, const btVector3 &v1, btScalar rt)
Definition: btVector3.h:492
btVector3::dot
btScalar dot(const btVector3 &v) const
Return the dot product.
Definition: btVector3.h:229
btVector3::setValue
void setValue(const btScalar &_x, const btScalar &_y, const btScalar &_z)
Definition: btVector3.h:640
btConvexCast::CastResult
RayResult stores the closest result alternatively, add a callback method to decide about closest/all ...
Definition: btConvexCast.h:47
btConvexCast::CastResult::m_normal
btVector3 m_normal
Definition: btConvexCast.h:70
btConvexCast::CastResult::m_fraction
btScalar m_fraction
Definition: btConvexCast.h:72
btConvexCast::CastResult::m_allowedPenetration
btScalar m_allowedPenetration
Definition: btConvexCast.h:74
btConvexCast::CastResult::m_hitPoint
btVector3 m_hitPoint
Definition: btConvexCast.h:71
btConvexCast::CastResult::DebugDraw
virtual void DebugDraw(btScalar fraction)
Definition: btConvexCast.h:50
btDiscreteCollisionDetectorInterface::ClosestPointInput
Definition: btDiscreteCollisionDetectorInterface.h:40
btDiscreteCollisionDetectorInterface::ClosestPointInput::m_transformB
btTransform m_transformB
Definition: btDiscreteCollisionDetectorInterface.h:47
btDiscreteCollisionDetectorInterface::ClosestPointInput::m_transformA
btTransform m_transformA
Definition: btDiscreteCollisionDetectorInterface.h:46
btPointCollector
Definition: btPointCollector.h:22
btPointCollector::m_normalOnBInWorld
btVector3 m_normalOnBInWorld
Definition: btPointCollector.h:23
btPointCollector::m_distance
btScalar m_distance
Definition: btPointCollector.h:25
btPointCollector::m_hasResult
bool m_hasResult
Definition: btPointCollector.h:27
btPointCollector::m_pointInWorld
btVector3 m_pointInWorld
Definition: btPointCollector.h:24