1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
|
#if 0
/*
Bullet Continuous Collision Detection and Physics Library
Copyright (c) 2003-2006 Erwin Coumans http://continuousphysics.com/Bullet/
This software is provided 'as-is', without any express or implied warranty.
In no event will the authors be held liable for any damages arising from the use of this software.
Permission is granted to anyone to use this software for any purpose,
including commercial applications, and to alter it and redistribute it freely,
subject to the following restrictions:
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.
2. Altered source versions must be plainly marked as such, and must not be misrepresented as being the original software.
3. This notice may not be removed or altered from any source distribution.
*/
#include "b3ContactCache.h"
#include "Bullet3Common/b3Transform.h"
#include "Bullet3Collision/NarrowPhaseCollision/shared/b3Contact4Data.h"
b3Scalar gContactBreakingThreshold = b3Scalar(0.02);
///gContactCalcArea3Points will approximate the convex hull area using 3 points
///when setting it to false, it will use 4 points to compute the area: it is more accurate but slower
bool gContactCalcArea3Points = true;
static inline b3Scalar calcArea4Points(const b3Vector3 &p0,const b3Vector3 &p1,const b3Vector3 &p2,const b3Vector3 &p3)
{
// It calculates possible 3 area constructed from random 4 points and returns the biggest one.
b3Vector3 a[3],b[3];
a[0] = p0 - p1;
a[1] = p0 - p2;
a[2] = p0 - p3;
b[0] = p2 - p3;
b[1] = p1 - p3;
b[2] = p1 - p2;
//todo: Following 3 cross production can be easily optimized by SIMD.
b3Vector3 tmp0 = a[0].cross(b[0]);
b3Vector3 tmp1 = a[1].cross(b[1]);
b3Vector3 tmp2 = a[2].cross(b[2]);
return b3Max(b3Max(tmp0.length2(),tmp1.length2()),tmp2.length2());
}
#if 0
//using localPointA for all points
int b3ContactCache::sortCachedPoints(const b3Vector3& pt)
{
//calculate 4 possible cases areas, and take biggest area
//also need to keep 'deepest'
int maxPenetrationIndex = -1;
#define KEEP_DEEPEST_POINT 1
#ifdef KEEP_DEEPEST_POINT
b3Scalar maxPenetration = pt.getDistance();
for (int i=0;i<4;i++)
{
if (m_pointCache[i].getDistance() < maxPenetration)
{
maxPenetrationIndex = i;
maxPenetration = m_pointCache[i].getDistance();
}
}
#endif //KEEP_DEEPEST_POINT
b3Scalar res0(b3Scalar(0.)),res1(b3Scalar(0.)),res2(b3Scalar(0.)),res3(b3Scalar(0.));
if (gContactCalcArea3Points)
{
if (maxPenetrationIndex != 0)
{
b3Vector3 a0 = pt.m_localPointA-m_pointCache[1].m_localPointA;
b3Vector3 b0 = m_pointCache[3].m_localPointA-m_pointCache[2].m_localPointA;
b3Vector3 cross = a0.cross(b0);
res0 = cross.length2();
}
if (maxPenetrationIndex != 1)
{
b3Vector3 a1 = pt.m_localPointA-m_pointCache[0].m_localPointA;
b3Vector3 b1 = m_pointCache[3].m_localPointA-m_pointCache[2].m_localPointA;
b3Vector3 cross = a1.cross(b1);
res1 = cross.length2();
}
if (maxPenetrationIndex != 2)
{
b3Vector3 a2 = pt.m_localPointA-m_pointCache[0].m_localPointA;
b3Vector3 b2 = m_pointCache[3].m_localPointA-m_pointCache[1].m_localPointA;
b3Vector3 cross = a2.cross(b2);
res2 = cross.length2();
}
if (maxPenetrationIndex != 3)
{
b3Vector3 a3 = pt.m_localPointA-m_pointCache[0].m_localPointA;
b3Vector3 b3 = m_pointCache[2].m_localPointA-m_pointCache[1].m_localPointA;
b3Vector3 cross = a3.cross(b3);
res3 = cross.length2();
}
}
else
{
if(maxPenetrationIndex != 0) {
res0 = calcArea4Points(pt.m_localPointA,m_pointCache[1].m_localPointA,m_pointCache[2].m_localPointA,m_pointCache[3].m_localPointA);
}
if(maxPenetrationIndex != 1) {
res1 = calcArea4Points(pt.m_localPointA,m_pointCache[0].m_localPointA,m_pointCache[2].m_localPointA,m_pointCache[3].m_localPointA);
}
if(maxPenetrationIndex != 2) {
res2 = calcArea4Points(pt.m_localPointA,m_pointCache[0].m_localPointA,m_pointCache[1].m_localPointA,m_pointCache[3].m_localPointA);
}
if(maxPenetrationIndex != 3) {
res3 = calcArea4Points(pt.m_localPointA,m_pointCache[0].m_localPointA,m_pointCache[1].m_localPointA,m_pointCache[2].m_localPointA);
}
}
b3Vector4 maxvec(res0,res1,res2,res3);
int biggestarea = maxvec.closestAxis4();
return biggestarea;
}
int b3ContactCache::getCacheEntry(const b3Vector3& newPoint) const
{
b3Scalar shortestDist = getContactBreakingThreshold() * getContactBreakingThreshold();
int size = getNumContacts();
int nearestPoint = -1;
for( int i = 0; i < size; i++ )
{
const b3Vector3 &mp = m_pointCache[i];
b3Vector3 diffA = mp.m_localPointA- newPoint.m_localPointA;
const b3Scalar distToManiPoint = diffA.dot(diffA);
if( distToManiPoint < shortestDist )
{
shortestDist = distToManiPoint;
nearestPoint = i;
}
}
return nearestPoint;
}
int b3ContactCache::addManifoldPoint(const b3Vector3& newPoint)
{
b3Assert(validContactDistance(newPoint));
int insertIndex = getNumContacts();
if (insertIndex == MANIFOLD_CACHE_SIZE)
{
#if MANIFOLD_CACHE_SIZE >= 4
//sort cache so best points come first, based on area
insertIndex = sortCachedPoints(newPoint);
#else
insertIndex = 0;
#endif
clearUserCache(m_pointCache[insertIndex]);
} else
{
m_cachedPoints++;
}
if (insertIndex<0)
insertIndex=0;
//b3Assert(m_pointCache[insertIndex].m_userPersistentData==0);
m_pointCache[insertIndex] = newPoint;
return insertIndex;
}
#endif
bool b3ContactCache::validContactDistance(const b3Vector3& pt)
{
return pt.w <= gContactBreakingThreshold;
}
void b3ContactCache::removeContactPoint(struct b3Contact4Data& newContactCache,int i)
{
int numContacts = b3Contact4Data_getNumPoints(&newContactCache);
if (i!=(numContacts-1))
{
b3Swap(newContactCache.m_localPosA[i],newContactCache.m_localPosA[numContacts-1]);
b3Swap(newContactCache.m_localPosB[i],newContactCache.m_localPosB[numContacts-1]);
b3Swap(newContactCache.m_worldPosB[i],newContactCache.m_worldPosB[numContacts-1]);
}
b3Contact4Data_setNumPoints(&newContactCache,numContacts-1);
}
void b3ContactCache::refreshContactPoints(const b3Transform& trA,const b3Transform& trB, struct b3Contact4Data& contacts)
{
int numContacts = b3Contact4Data_getNumPoints(&contacts);
int i;
/// first refresh worldspace positions and distance
for (i=numContacts-1;i>=0;i--)
{
b3Vector3 worldPosA = trA( contacts.m_localPosA[i]);
b3Vector3 worldPosB = trB( contacts.m_localPosB[i]);
contacts.m_worldPosB[i] = worldPosB;
float distance = (worldPosA - worldPosB).dot(contacts.m_worldNormalOnB);
contacts.m_worldPosB[i].w = distance;
}
/// then
b3Scalar distance2d;
b3Vector3 projectedDifference,projectedPoint;
for (i=numContacts-1;i>=0;i--)
{
b3Vector3 worldPosA = trA( contacts.m_localPosA[i]);
b3Vector3 worldPosB = trB( contacts.m_localPosB[i]);
b3Vector3&pt = contacts.m_worldPosB[i];
//contact becomes invalid when signed distance exceeds margin (projected on contactnormal direction)
if (!validContactDistance(pt))
{
removeContactPoint(contacts,i);
} else
{
//contact also becomes invalid when relative movement orthogonal to normal exceeds margin
projectedPoint = worldPosA - contacts.m_worldNormalOnB * contacts.m_worldPosB[i].w;
projectedDifference = contacts.m_worldPosB[i] - projectedPoint;
distance2d = projectedDifference.dot(projectedDifference);
if (distance2d > gContactBreakingThreshold*gContactBreakingThreshold )
{
removeContactPoint(contacts,i);
} else
{
////contact point processed callback
//if (gContactProcessedCallback)
// (*gContactProcessedCallback)(manifoldPoint,(void*)m_body0,(void*)m_body1);
}
}
}
}
#endif
|