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

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btContactProcessing.cpp
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1
2/*
3This source file is part of GIMPACT Library.
4
5For the latest info, see http://gimpact.sourceforge.net/
6
7Copyright (c) 2007 Francisco Leon Najera. C.C. 80087371.
8email: projectileman@yahoo.com
9
10
11This software is provided 'as-is', without any express or implied warranty.
12In no event will the authors be held liable for any damages arising from the use of this software.
13Permission is granted to anyone to use this software for any purpose,
14including commercial applications, and to alter it and redistribute it freely,
15subject to the following restrictions:
16
171. 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.
182. Altered source versions must be plainly marked as such, and must not be misrepresented as being the original software.
193. This notice may not be removed or altered from any source distribution.
20*/
21#include "btContactProcessing.h"
22
23#define MAX_COINCIDENT 8
24
25 struct CONTACT_KEY_TOKEN
26{
27 unsigned int m_key;
28 int m_value;
29 CONTACT_KEY_TOKEN()
30 {
31 }
32
33 CONTACT_KEY_TOKEN(unsigned int key, int token)
34 {
35 m_key = key;
36 m_value = token;
37 }
38
39 CONTACT_KEY_TOKEN(const CONTACT_KEY_TOKEN& rtoken)
40 {
41 m_key = rtoken.m_key;
42 m_value = rtoken.m_value;
43 }
44
45 inline bool operator<(const CONTACT_KEY_TOKEN& other) const
46 {
47 return (m_key < other.m_key);
48 }
49
50 inline bool operator>(const CONTACT_KEY_TOKEN& other) const
51 {
52 return (m_key > other.m_key);
53 }
54};
55
56 class CONTACT_KEY_TOKEN_COMP
57{
58public:
59 bool operator()(const CONTACT_KEY_TOKEN& a, const CONTACT_KEY_TOKEN& b) const
60 {
61 return (a < b);
62 }
63};
64
65 void btContactArray::merge_contacts(
66 const btContactArray& contacts, bool normal_contact_average)
67{
68 clear();
69
70 int i;
71 if (contacts.size() == 0) return;
72
73 if (contacts.size() == 1)
74 {
75 push_back(contacts[0]);
76 return;
77 }
78
79 btAlignedObjectArray<CONTACT_KEY_TOKEN> keycontacts;
80
81 keycontacts.reserve(contacts.size());
82
83 //fill key contacts
84
85 for (i = 0; i < contacts.size(); i++)
86 {
87 keycontacts.push_back(CONTACT_KEY_TOKEN(contacts[i].calc_key_contact(), i));
88 }
89
90 //sort keys
91 keycontacts.quickSort(CONTACT_KEY_TOKEN_COMP());
92
93 // Merge contacts
94 int coincident_count = 0;
95 btVector3 coincident_normals[MAX_COINCIDENT];
96
97 unsigned int last_key = keycontacts[0].m_key;
98 unsigned int key = 0;
99
100 push_back(contacts[keycontacts[0].m_value]);
101
102 GIM_CONTACT* pcontact = &(*this)[0];
103
104 for (i = 1; i < keycontacts.size(); i++)
105 {
106 key = keycontacts[i].m_key;
107 const GIM_CONTACT* scontact = &contacts[keycontacts[i].m_value];
108
109 if (last_key == key) //same points
110 {
111 //merge contact
112 if (pcontact->m_depth - CONTACT_DIFF_EPSILON > scontact->m_depth) //)
113 {
114 *pcontact = *scontact;
115 coincident_count = 0;
116 }
117 else if (normal_contact_average)
118 {
119 if (btFabs(pcontact->m_depth - scontact->m_depth) < CONTACT_DIFF_EPSILON)
120 {
121 if (coincident_count < MAX_COINCIDENT)
122 {
123 coincident_normals[coincident_count] = scontact->m_normal;
124 coincident_count++;
125 }
126 }
127 }
128 }
129 else
130 { //add new contact
131
132 if (normal_contact_average && coincident_count > 0)
133 {
134 pcontact->interpolate_normals(coincident_normals, coincident_count);
135 coincident_count = 0;
136 }
137
138 push_back(*scontact);
139 pcontact = &(*this)[this->size() - 1];
140 }
141 last_key = key;
142 }
143}
144
145 void btContactArray::merge_contacts_unique(const btContactArray& contacts)
146{
147 clear();
148
149 if (contacts.size() == 0) return;
150
151 if (contacts.size() == 1)
152 {
153 push_back(contacts[0]);
154 return;
155 }
156
157 GIM_CONTACT average_contact = contacts[0];
158
159 for (int i = 1; i < contacts.size(); i++)
160 {
161 average_contact.m_point += contacts[i].m_point;
162 average_contact.m_normal += contacts[i].m_normal * contacts[i].m_depth;
163 }
164
165 //divide
166 btScalar divide_average = 1.0f / ((btScalar)contacts.size());
167
168 average_contact.m_point *= divide_average;
169
170 average_contact.m_normal *= divide_average;
171
172 average_contact.m_depth = average_contact.m_normal.length();
173
174 average_contact.m_normal /= average_contact.m_depth;
175}
CONTACT_DIFF_EPSILON
#define CONTACT_DIFF_EPSILON
Definition: btContactProcessingStructs.h:36
MAX_COINCIDENT
#define MAX_COINCIDENT
Definition: btContactProcessing.cpp:23
btContactProcessing.h
btScalar
float btScalar
The btScalar type abstracts floating point numbers, to easily switch between double and single floati...
Definition: btScalar.h:314
btFabs
btScalar btFabs(btScalar x)
Definition: btScalar.h:497
CONTACT_KEY_TOKEN_COMP
Definition: btContactProcessing.cpp:57
CONTACT_KEY_TOKEN_COMP::operator()
bool operator()(const CONTACT_KEY_TOKEN &a, const CONTACT_KEY_TOKEN &b) const
Definition: btContactProcessing.cpp:59
GIM_CONTACT
The GIM_CONTACT is an internal GIMPACT structure, similar to btManifoldPoint.
Definition: btContactProcessingStructs.h:41
GIM_CONTACT::m_point
btVector3 m_point
Definition: btContactProcessingStructs.h:43
GIM_CONTACT::interpolate_normals
void interpolate_normals(btVector3 *normals, int normal_count)
Definition: btContactProcessingStructs.h:88
GIM_CONTACT::m_depth
btScalar m_depth
Definition: btContactProcessingStructs.h:45
GIM_CONTACT::m_normal
btVector3 m_normal
Definition: btContactProcessingStructs.h:44
btAlignedObjectArray
The btAlignedObjectArray template class uses a subset of the stl::vector interface for its methods It...
Definition: btAlignedObjectArray.h:46
btAlignedObjectArray::size
int size() const
return the number of elements in the array
Definition: btAlignedObjectArray.h:142
btAlignedObjectArray< GIM_CONTACT >::clear
void clear()
clear the array, deallocated memory. Generally it is better to use array.resize(0),...
Definition: btAlignedObjectArray.h:176
btAlignedObjectArray::quickSort
void quickSort(const L &CompareFunc)
Definition: btAlignedObjectArray.h:341
btAlignedObjectArray< GIM_CONTACT >::push_back
void push_back(const GIM_CONTACT &_Val)
Definition: btAlignedObjectArray.h:257
btAlignedObjectArray::reserve
void reserve(int _Count)
Definition: btAlignedObjectArray.h:280
btContactArray
Definition: btContactProcessing.h:33
btContactArray::merge_contacts_unique
void merge_contacts_unique(const btContactArray &contacts)
Definition: btContactProcessing.cpp:145
btContactArray::merge_contacts
void merge_contacts(const btContactArray &contacts, bool normal_contact_average=true)
Definition: btContactProcessing.cpp:65
btVector3
btVector3 can be used to represent 3D points and vectors.
Definition: btVector3.h:82
btVector3::length
btScalar length() const
Return the length of the vector.
Definition: btVector3.h:257
CONTACT_KEY_TOKEN
Definition: btContactProcessing.cpp:26
CONTACT_KEY_TOKEN::m_value
int m_value
Definition: btContactProcessing.cpp:28
CONTACT_KEY_TOKEN::operator<
bool operator<(const CONTACT_KEY_TOKEN &other) const
Definition: btContactProcessing.cpp:45
CONTACT_KEY_TOKEN::CONTACT_KEY_TOKEN
CONTACT_KEY_TOKEN(unsigned int key, int token)
Definition: btContactProcessing.cpp:33
CONTACT_KEY_TOKEN::CONTACT_KEY_TOKEN
CONTACT_KEY_TOKEN(const CONTACT_KEY_TOKEN &rtoken)
Definition: btContactProcessing.cpp:39
CONTACT_KEY_TOKEN::m_key
unsigned int m_key
Definition: btContactProcessing.cpp:27
CONTACT_KEY_TOKEN::operator>
bool operator>(const CONTACT_KEY_TOKEN &other) const
Definition: btContactProcessing.cpp:50
CONTACT_KEY_TOKEN::CONTACT_KEY_TOKEN
CONTACT_KEY_TOKEN()
Definition: btContactProcessing.cpp:29