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      1 
      2 /*
      3 -----------------------------------------------------------------------------
      4 This source file is part of GIMPACT Library.
      5 
      6 For the latest info, see http://gimpact.sourceforge.net/
      7 
      8 Copyright (c) 2006 Francisco Leon Najera. C.C. 80087371.
      9 email: projectileman (at) 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 
     74 
     75 	for( i=1;i<keycontacts.size();i++)
     76 	{
     77 	    key = keycontacts[i].m_key;
     78 		const GIM_CONTACT * scontact = &contacts[keycontacts[i].m_value];
     79 
     80 		if(last_key ==  key)//same points
     81 		{
     82 			//merge contact
     83 			if(pcontact->m_depth - CONTACT_DIFF_EPSILON > scontact->m_depth)//)
     84 			{
     85 				*pcontact = *scontact;
     86                 coincident_count = 0;
     87 			}
     88 			else if(normal_contact_average)
     89 			{
     90 				if(btFabs(pcontact->m_depth - scontact->m_depth)<CONTACT_DIFF_EPSILON)
     91                 {
     92                     if(coincident_count<MAX_COINCIDENT)
     93                     {
     94                     	coincident_normals[coincident_count] = scontact->m_normal;
     95                         coincident_count++;
     96                     }
     97                 }
     98 			}
     99 		}
    100 		else
    101 		{//add new contact
    102 
    103 		    if(normal_contact_average && coincident_count>0)
    104 		    {
    105 		    	pcontact->interpolate_normals(coincident_normals,coincident_count);
    106 		        coincident_count = 0;
    107 		    }
    108 
    109 		    push_back(*scontact);
    110 		    pcontact = &back();
    111         }
    112 		last_key = key;
    113 	}
    114 }
    115 
    116 void gim_contact_array::merge_contacts_unique(const gim_contact_array & contacts)
    117 {
    118 	clear();
    119 
    120 	if(contacts.size()==1)
    121 	{
    122 		push_back(contacts.back());
    123 		return;
    124 	}
    125 
    126 	GIM_CONTACT average_contact = contacts.back();
    127 
    128 	for (GUINT i=1;i<contacts.size() ;i++ )
    129 	{
    130 		average_contact.m_point += contacts[i].m_point;
    131 		average_contact.m_normal += contacts[i].m_normal * contacts[i].m_depth;
    132 	}
    133 
    134 	//divide
    135 	GREAL divide_average = 1.0f/((GREAL)contacts.size());
    136 
    137 	average_contact.m_point *= divide_average;
    138 
    139 	average_contact.m_normal *= divide_average;
    140 
    141 	average_contact.m_depth = average_contact.m_normal.length();
    142 
    143 	average_contact.m_normal /= average_contact.m_depth;
    144 
    145 }
    146 
    147