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

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gim_contact.cpp
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1
2/*
3-----------------------------------------------------------------------------
4This source file is part of GIMPACT Library.
5
6For the latest info, see http://gimpact.sourceforge.net/
7
8Copyright (c) 2006 Francisco Leon Najera. C.C. 80087371.
9email: projectileman@yahoo.com
10
11 This library is free software; you can redistribute it and/or
12 modify it under the terms of EITHER:
13 (1) The GNU Lesser General Public License as published by the Free
14 Software Foundation; either version 2.1 of the License, or (at
15 your option) any later version. The text of the GNU Lesser
16 General Public License is included with this library in the
17 file GIMPACT-LICENSE-LGPL.TXT.
18 (2) The BSD-style license that is included with this library in
19 the file GIMPACT-LICENSE-BSD.TXT.
20 (3) The zlib/libpng license that is included with this library in
21 the file GIMPACT-LICENSE-ZLIB.TXT.
22
23 This library is distributed in the hope that it will be useful,
24 but WITHOUT ANY WARRANTY; without even the implied warranty of
25 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the files
26 GIMPACT-LICENSE-LGPL.TXT, GIMPACT-LICENSE-ZLIB.TXT and GIMPACT-LICENSE-BSD.TXT for more details.
27
28-----------------------------------------------------------------------------
29*/
30
31#include "gim_contact.h"
32
33#define MAX_COINCIDENT 8
34
35 void gim_contact_array::merge_contacts(
36 const gim_contact_array& contacts, bool normal_contact_average)
37{
38 clear();
39
40 if (contacts.size() == 1)
41 {
42 push_back(contacts.back());
43 return;
44 }
45
46 gim_array<GIM_RSORT_TOKEN> keycontacts(contacts.size());
47 keycontacts.resize(contacts.size(), false);
48
49 //fill key contacts
50
51 GUINT i;
52
53 for (i = 0; i < contacts.size(); i++)
54 {
55 keycontacts[i].m_key = contacts[i].calc_key_contact();
56 keycontacts[i].m_value = i;
57 }
58
59 //sort keys
60 gim_heap_sort(keycontacts.pointer(), keycontacts.size(), GIM_RSORT_TOKEN_COMPARATOR());
61
62 // Merge contacts
63
64 GUINT coincident_count = 0;
65 btVector3 coincident_normals[MAX_COINCIDENT];
66
67 GUINT last_key = keycontacts[0].m_key;
68 GUINT key = 0;
69
70 push_back(contacts[keycontacts[0].m_value]);
71 GIM_CONTACT* pcontact = &back();
72
73 for (i = 1; i < keycontacts.size(); i++)
74 {
75 key = keycontacts[i].m_key;
76 const GIM_CONTACT* scontact = &contacts[keycontacts[i].m_value];
77
78 if (last_key == key) //same points
79 {
80 //merge contact
81 if (pcontact->m_depth - CONTACT_DIFF_EPSILON > scontact->m_depth) //)
82 {
83 *pcontact = *scontact;
84 coincident_count = 0;
85 }
86 else if (normal_contact_average)
87 {
88 if (btFabs(pcontact->m_depth - scontact->m_depth) < CONTACT_DIFF_EPSILON)
89 {
90 if (coincident_count < MAX_COINCIDENT)
91 {
92 coincident_normals[coincident_count] = scontact->m_normal;
93 coincident_count++;
94 }
95 }
96 }
97 }
98 else
99 { //add new contact
100
101 if (normal_contact_average && coincident_count > 0)
102 {
103 pcontact->interpolate_normals(coincident_normals, coincident_count);
104 coincident_count = 0;
105 }
106
107 push_back(*scontact);
108 pcontact = &back();
109 }
110 last_key = key;
111 }
112}
113
114 void gim_contact_array::merge_contacts_unique(const gim_contact_array& contacts)
115{
116 clear();
117
118 if (contacts.size() == 1)
119 {
120 push_back(contacts.back());
121 return;
122 }
123
124 GIM_CONTACT average_contact = contacts.back();
125
126 for (GUINT i = 1; i < contacts.size(); i++)
127 {
128 average_contact.m_point += contacts[i].m_point;
129 average_contact.m_normal += contacts[i].m_normal * contacts[i].m_depth;
130 }
131
132 //divide
133 GREAL divide_average = 1.0f / ((GREAL)contacts.size());
134
135 average_contact.m_point *= divide_average;
136
137 average_contact.m_normal *= divide_average;
138
139 average_contact.m_depth = average_contact.m_normal.length();
140
141 average_contact.m_normal /= average_contact.m_depth;
142}
MAX_COINCIDENT
#define MAX_COINCIDENT
Definition btContactProcessing.cpp:23
btFabs
btScalar btFabs(btScalar x)
Definition btScalar.h:497
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
GIM_RSORT_TOKEN_COMPARATOR
Prototype for comparators.
Definition gim_radixsort.h:122
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
gim_array
Very simple array container with fast access and simd memory.
Definition gim_array.h:43
gim_array::back
T & back()
Definition gim_array.h:198
gim_array< GIM_CONTACT >::push_back
void push_back(const GIM_CONTACT &obj)
Definition gim_array.h:213
gim_array::size
GUINT size() const
Definition gim_array.h:143
gim_array::resize
void resize(GUINT size, bool call_constructor=true, const T &fillData=T())
Definition gim_array.h:287
gim_array< GIM_CONTACT >::clear
void clear()
Definition gim_array.h:110
gim_array::pointer
T * pointer()
Definition gim_array.h:162
gim_contact_array
Definition gim_contact.h:130
gim_contact_array::merge_contacts
void merge_contacts(const gim_contact_array &contacts, bool normal_contact_average=true)
Definition gim_contact.cpp:35
gim_contact_array::merge_contacts_unique
void merge_contacts_unique(const gim_contact_array &contacts)
Definition gim_contact.cpp:114
gim_contact.h
CONTACT_DIFF_EPSILON
#define CONTACT_DIFF_EPSILON
Definition gim_contact.h:47
GREAL
#define GREAL
Definition gim_math.h:37
GUINT
#define GUINT
Definition gim_math.h:40
gim_heap_sort
void gim_heap_sort(T *pArr, GUINT element_count, COMP_CLASS CompareFunc)
Definition gim_radixsort.h:366