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[blender.git] / extern / bullet2 / src / BulletCollision / NarrowPhaseCollision / btSubSimplexConvexCast.cpp
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
17 #include "btSubSimplexConvexCast.h"
18 #include "BulletCollision/CollisionShapes/btConvexShape.h"
19
20 #include "BulletCollision/CollisionShapes/btMinkowskiSumShape.h"
21 #include "BulletCollision/NarrowPhaseCollision/btSimplexSolverInterface.h"
22 #include "btPointCollector.h"
23 #include "LinearMath/btTransformUtil.h"
24
25 btSubsimplexConvexCast::btSubsimplexConvexCast (const btConvexShape* convexA,const btConvexShape* convexB,btSimplexSolverInterface* simplexSolver)
26 :m_simplexSolver(simplexSolver),
27 m_convexA(convexA),m_convexB(convexB)
28 {
29 }
30
31 ///Typically the conservative advancement reaches solution in a few iterations, clip it to 32 for degenerate cases.
32 ///See discussion about this here http://continuousphysics.com/Bullet/phpBB2/viewtopic.php?t=565
33 #ifdef BT_USE_DOUBLE_PRECISION
34 #define MAX_ITERATIONS 64
35 #else
36 #define MAX_ITERATIONS 32
37 #endif
38 bool    btSubsimplexConvexCast::calcTimeOfImpact(
39                 const btTransform& fromA,
40                 const btTransform& toA,
41                 const btTransform& fromB,
42                 const btTransform& toB,
43                 CastResult& result)
44 {
45
46         m_simplexSolver->reset();
47
48         btVector3 linVelA,linVelB;
49         linVelA = toA.getOrigin()-fromA.getOrigin();
50         linVelB = toB.getOrigin()-fromB.getOrigin();
51
52         btScalar lambda = btScalar(0.);
53
54         btTransform interpolatedTransA = fromA;
55         btTransform interpolatedTransB = fromB;
56
57         ///take relative motion
58         btVector3 r = (linVelA-linVelB);
59         btVector3 v;
60         
61         btVector3 supVertexA = fromA(m_convexA->localGetSupportingVertex(-r*fromA.getBasis()));
62         btVector3 supVertexB = fromB(m_convexB->localGetSupportingVertex(r*fromB.getBasis()));
63         v = supVertexA-supVertexB;
64         int maxIter = MAX_ITERATIONS;
65
66         btVector3 n;
67         n.setValue(btScalar(0.),btScalar(0.),btScalar(0.));
68         bool hasResult = false;
69         btVector3 c;
70
71         btScalar lastLambda = lambda;
72
73
74         btScalar dist2 = v.length2();
75 #ifdef BT_USE_DOUBLE_PRECISION
76         btScalar epsilon = btScalar(0.0001);
77 #else
78         btScalar epsilon = btScalar(0.0001);
79 #endif //BT_USE_DOUBLE_PRECISION
80         btVector3       w,p;
81         btScalar VdotR;
82         
83         while ( (dist2 > epsilon) && maxIter--)
84         {
85                 supVertexA = interpolatedTransA(m_convexA->localGetSupportingVertex(-v*interpolatedTransA.getBasis()));
86                 supVertexB = interpolatedTransB(m_convexB->localGetSupportingVertex(v*interpolatedTransB.getBasis()));
87                 w = supVertexA-supVertexB;
88
89                 btScalar VdotW = v.dot(w);
90
91                 if (lambda > btScalar(1.0))
92                 {
93                         return false;
94                 }
95
96                 if ( VdotW > btScalar(0.))
97                 {
98                         VdotR = v.dot(r);
99
100                         if (VdotR >= -(SIMD_EPSILON*SIMD_EPSILON))
101                                 return false;
102                         else
103                         {
104                                 lambda = lambda - VdotW / VdotR;
105                                 //interpolate to next lambda
106                                 //      x = s + lambda * r;
107                                 interpolatedTransA.getOrigin().setInterpolate3(fromA.getOrigin(),toA.getOrigin(),lambda);
108                                 interpolatedTransB.getOrigin().setInterpolate3(fromB.getOrigin(),toB.getOrigin(),lambda);
109                                 //m_simplexSolver->reset();
110                                 //check next line
111                                  w = supVertexA-supVertexB;
112                                 lastLambda = lambda;
113                                 n = v;
114                                 hasResult = true;
115                         }
116                 } 
117                 m_simplexSolver->addVertex( w, supVertexA , supVertexB);
118                 if (m_simplexSolver->closest(v))
119                 {
120                         dist2 = v.length2();
121                         hasResult = true;
122                         //todo: check this normal for validity
123                         //n=v;
124                         //printf("V=%f , %f, %f\n",v[0],v[1],v[2]);
125                         //printf("DIST2=%f\n",dist2);
126                         //printf("numverts = %i\n",m_simplexSolver->numVertices());
127                 } else
128                 {
129                         dist2 = btScalar(0.);
130                 } 
131         }
132
133         //int numiter = MAX_ITERATIONS - maxIter;
134 //      printf("number of iterations: %d", numiter);
135         
136         //don't report a time of impact when moving 'away' from the hitnormal
137         
138
139         result.m_fraction = lambda;
140         if (n.length2() >= (SIMD_EPSILON*SIMD_EPSILON))
141                 result.m_normal = n.normalized();
142         else
143                 result.m_normal = btVector3(btScalar(0.0), btScalar(0.0), btScalar(0.0));
144
145         //don't report time of impact for motion away from the contact normal (or causes minor penetration)
146         if (result.m_normal.dot(r)>=-result.m_allowedPenetration)
147                 return false;
148
149         btVector3 hitA,hitB;
150         m_simplexSolver->compute_points(hitA,hitB);
151         result.m_hitPoint=hitB;
152         return true;
153 }
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