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
|
/*
* Copyright (c) 2005 Erwin Coumans http://www.erwincoumans.com
*
* Permission to use, copy, modify, distribute and sell this software
* and its documentation for any purpose is hereby granted without fee,
* provided that the above copyright notice appear in all copies.
* Erwin Coumans makes no representations about the suitability
* of this software for any purpose.
* It is provided "as is" without express or implied warranty.
*/
#include "PersistentManifold.h"
#include "SimdTransform.h"
#include <assert.h>
float gContactBreakingTreshold = 0.02f;
PersistentManifold::PersistentManifold()
:m_body0(0),
m_body1(0),
m_cachedPoints (0),
m_index1(0)
{
}
void PersistentManifold::ClearManifold()
{
m_cachedPoints = 0;
}
int PersistentManifold::SortCachedPoints(const ManifoldPoint& pt)
{
//calculate 4 possible cases areas, and take biggest area
SimdScalar res0,res1,res2,res3;
{
SimdVector3 a0 = pt.m_localPointA-m_pointCache[1].m_localPointA;
SimdVector3 b0 = m_pointCache[3].m_localPointA-m_pointCache[2].m_localPointA;
SimdVector3 cross = a0.cross(b0);
res0 = cross.length2();
}
{
SimdVector3 a1 = pt.m_localPointA-m_pointCache[0].m_localPointA;
SimdVector3 b1 = m_pointCache[3].m_localPointA-m_pointCache[2].m_localPointA;
SimdVector3 cross = a1.cross(b1);
res1 = cross.length2();
}
{
SimdVector3 a2 = pt.m_localPointA-m_pointCache[0].m_localPointA;
SimdVector3 b2 = m_pointCache[3].m_localPointA-m_pointCache[1].m_localPointA;
SimdVector3 cross = a2.cross(b2);
res2 = cross.length2();
}
{
SimdVector3 a3 = pt.m_localPointA-m_pointCache[0].m_localPointA;
SimdVector3 b3 = m_pointCache[2].m_localPointA-m_pointCache[1].m_localPointA;
SimdVector3 cross = a3.cross(b3);
res3 = cross.length2();
}
SimdVector4 maxvec(res0,res1,res2,res3);
int biggestarea = maxvec.closestAxis4();
return biggestarea;
}
int PersistentManifold::GetCacheEntry(const ManifoldPoint& newPoint) const
{
SimdScalar shortestDist = GetManifoldMargin() * GetManifoldMargin();
int size = GetNumContacts();
int nearestPoint = -1;
for( int i = 0; i < size; i++ )
{
const ManifoldPoint &mp = m_pointCache[i];
SimdVector3 diffA = mp.m_localPointA- newPoint.m_localPointA;
const SimdScalar distToManiPoint = diffA.dot(diffA);
if( distToManiPoint < shortestDist )
{
shortestDist = distToManiPoint;
nearestPoint = i;
}
}
return nearestPoint;
}
void PersistentManifold::AddManifoldPoint(const ManifoldPoint& newPoint)
{
assert(ValidContactDistance(newPoint));
int insertIndex = GetNumContacts();
if (insertIndex == MANIFOLD_CACHE_SIZE)
{
//sort cache so best points come first
insertIndex = SortCachedPoints(newPoint);
} else
{
m_cachedPoints++;
}
ReplaceContactPoint(newPoint,insertIndex);
}
float PersistentManifold::GetManifoldMargin() const
{
return gContactBreakingTreshold;
}
void PersistentManifold::RefreshContactPoints(const SimdTransform& trA,const SimdTransform& trB)
{
int i;
/// first refresh worldspace positions and distance
for (i=GetNumContacts()-1;i>=0;i--)
{
ManifoldPoint &manifoldPoint = m_pointCache[i];
manifoldPoint.m_positionWorldOnA = trA( manifoldPoint.m_localPointA );
manifoldPoint.m_positionWorldOnB = trB( manifoldPoint.m_localPointB );
manifoldPoint.m_distance1 = (manifoldPoint.m_positionWorldOnA - manifoldPoint.m_positionWorldOnB).dot(manifoldPoint.m_normalWorldOnB);
}
/// then
SimdScalar distance2d;
SimdVector3 projectedDifference,projectedPoint;
for (i=GetNumContacts()-1;i>=0;i--)
{
ManifoldPoint &manifoldPoint = m_pointCache[i];
//contact becomes invalid when signed distance exceeds margin (projected on contactnormal direction)
if (!ValidContactDistance(manifoldPoint))
{
RemoveContactPoint(i);
} else
{
//contact also becomes invalid when relative movement orthogonal to normal exceeds margin
projectedPoint = manifoldPoint.m_positionWorldOnA - manifoldPoint.m_normalWorldOnB * manifoldPoint.m_distance1;
projectedDifference = manifoldPoint.m_positionWorldOnB - projectedPoint;
distance2d = projectedDifference.dot(projectedDifference);
if (distance2d > GetManifoldMargin()*GetManifoldMargin() )
{
RemoveContactPoint(i);
}
}
}
}
//todo: remove this treshold
float gPenetrationDistanceCheck = -0.05f;
float PersistentManifold::GetCollisionImpulse() const
{
float averageImpulse = 0.f;
if (GetNumContacts() > 0)
{
float totalImpulse = 0.f;
//return the sum of the applied impulses on the box
for (int i=0;i<GetNumContacts();i++)
{
const ManifoldPoint& cp = GetContactPoint(i);
//avoid conflic noice
if ( cp.GetDistance() <gPenetrationDistanceCheck)
return 0.f;
totalImpulse += cp.m_appliedImpulse;
}
averageImpulse = totalImpulse / ((float)GetNumContacts());
}
return averageImpulse;
}
|
