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