1 /*
2 Bullet Continuous Collision Detection and Physics Library
3 Copyright (c) 2003-2006 Erwin Coumans https://bulletphysics.org
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
btGjkConvexCast(const btConvexShape * convexA,const btConvexShape * convexB,btSimplexSolverInterface * simplexSolver)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
calcTimeOfImpact(const btTransform & fromA,const btTransform & toA,const btTransform & fromB,const btTransform & toB,CastResult & result)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
44 /// compute linear velocity for this interval, to interpolate
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 }
165