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

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"
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
28 btGjkConvexCast::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 }
btTransformUtil.h
btConvexCast::CastResult::m_fraction
btScalar m_fraction
Definition: btConvexCast.h:72
btPointCollector.h
btVector3::setValue
void setValue(const btScalar &_x, const btScalar &_y, const btScalar &_z)
Definition: btVector3.h:640
btTransform::setIdentity
void setIdentity()
Set this transformation to the identity.
Definition: btTransform.h:166
btPointCollector::m_distance
btScalar m_distance
Definition: btPointCollector.h:25
btDiscreteCollisionDetectorInterface::ClosestPointInput::m_transformA
btTransform m_transformA
Definition: btDiscreteCollisionDetectorInterface.h:46
btGjkPairDetector.h
btDiscreteCollisionDetectorInterface::ClosestPointInput::m_transformB
btTransform m_transformB
Definition: btDiscreteCollisionDetectorInterface.h:47
btConvexCast::CastResult::m_normal
btVector3 m_normal
Definition: btConvexCast.h:70
btConvexShape
The btConvexShape is an abstract shape interface, implemented by all convex shapes such as btBoxShape...
Definition: btConvexShape.h:31
btConvexCast::CastResult::m_allowedPenetration
btScalar m_allowedPenetration
Definition: btConvexCast.h:74
btPointCollector
Definition: btPointCollector.h:21
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
btConvexCast::CastResult::DebugDraw
virtual void DebugDraw(btScalar fraction)
Definition: btConvexCast.h:50
btConvexCast::CastResult
RayResult stores the closest result alternatively, add a callback method to decide about closest/all ...
Definition: btConvexCast.h:46
btTransform::getOrigin
btVector3 & getOrigin()
Return the origin vector translation.
Definition: btTransform.h:113
btSimplexSolverInterface
#define btSimplexSolverInterface
Definition: btSimplexSolverInterface.h:24
btVector3::dot
btScalar dot(const btVector3 &v) const
Return the dot product.
Definition: btVector3.h:229
btGjkConvexCast.h
btPointCollector::m_pointInWorld
btVector3 m_pointInWorld
Definition: btPointCollector.h:24
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
btVector3
btVector3 can be used to represent 3D points and vectors.
Definition: btVector3.h:80
btGjkConvexCast::m_simplexSolver
btSimplexSolverInterface * m_simplexSolver
Definition: btGjkConvexCast.h:30
btTransform
The btTransform class supports rigid transforms with only translation and rotation and no scaling/she...
Definition: btTransform.h:28
btConvexCast::CastResult::m_hitPoint
btVector3 m_hitPoint
Definition: btConvexCast.h:71
btGjkPairDetector
btGjkPairDetector uses GJK to implement the btDiscreteCollisionDetectorInterface
Definition: btGjkPairDetector.h:27
MAX_ITERATIONS
#define MAX_ITERATIONS
Definition: btGjkConvexCast.cpp:25
btGjkConvexCast::m_convexB
const btConvexShape * m_convexB
Definition: btGjkConvexCast.h:32
btPointCollector::m_hasResult
bool m_hasResult
Definition: btPointCollector.h:27
btDiscreteCollisionDetectorInterface::ClosestPointInput
Definition: btDiscreteCollisionDetectorInterface.h:39
btSphereShape.h
btVector3::setInterpolate3
void setInterpolate3(const btVector3 &v0, const btVector3 &v1, btScalar rt)
Definition: btVector3.h:492
btPointCollector::m_normalOnBInWorld
btVector3 m_normalOnBInWorld
Definition: btPointCollector.h:23
btScalar
float btScalar
The btScalar type abstracts floating point numbers, to easily switch between double and single floati...
Definition: btScalar.h:294
btGjkPairDetector::getClosestPoints
virtual void getClosestPoints(const ClosestPointInput &input, Result &output, class btIDebugDraw *debugDraw, bool swapResults=false)
Definition: btGjkPairDetector.cpp:73