0b74b1bbf2
is a problem related to deleting triangles from the triangle pool as they are combined into fans.
242 lines
6.7 KiB
C++
242 lines
6.7 KiB
C++
// genfans.cxx -- Combine individual triangles into more optimal fans.
|
|
//
|
|
// Written by Curtis Olson, started March 1999.
|
|
//
|
|
// Copyright (C) 1999 Curtis L. Olson - curt@flightgear.org
|
|
//
|
|
// This program is free software; you can redistribute it and/or
|
|
// modify it under the terms of the GNU General Public License as
|
|
// published by the Free Software Foundation; either version 2 of the
|
|
// License, or (at your option) any later version.
|
|
//
|
|
// This program is distributed in the hope that it will be useful, but
|
|
// WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
|
|
// General Public License for more details.
|
|
//
|
|
// You should have received a copy of the GNU General Public License
|
|
// along with this program; if not, write to the Free Software
|
|
// Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
|
|
//
|
|
// $Id$
|
|
// (Log is kept at end of this file)
|
|
|
|
|
|
#include "genfans.hxx"
|
|
|
|
|
|
// make sure the list is expanded at least to hold "n" and then push
|
|
// "i" onto the back of the "n" list.
|
|
void FGGenFans::add_and_expand( reverse_list& by_node, int n, int i ) {
|
|
int_list empty;
|
|
|
|
int size = (int)by_node.size();
|
|
if ( size > n ) {
|
|
// ok
|
|
} else {
|
|
// cout << "capacity = " << by_node.capacity() << endl;
|
|
// cout << "size = " << size << " n = " << n
|
|
// << " need to push = " << n - size + 1 << endl;
|
|
for ( int i = 0; i < n - size + 1; ++i ) {
|
|
by_node.push_back(empty);
|
|
}
|
|
}
|
|
|
|
by_node[n].push_back(i);
|
|
}
|
|
|
|
|
|
// given an input triangle, shuffle nodes so that "center" is the
|
|
// first node, but maintain winding order.
|
|
static FGTriEle canonify( const FGTriEle& t, int center ) {
|
|
if ( t.get_n1() == center ) {
|
|
// already ok
|
|
return t;
|
|
} else if ( t.get_n2() == center ) {
|
|
return FGTriEle( t.get_n2(), t.get_n3(), t.get_n1(), 0.0 );
|
|
} else if ( t.get_n3() == center ) {
|
|
return FGTriEle( t.get_n3(), t.get_n1(), t.get_n2(), 0.0 );
|
|
} else {
|
|
cout << "ERROR, index doesn't refer to this triangle!!!" << endl;
|
|
exit(-1);
|
|
}
|
|
}
|
|
|
|
// returns a list of triangle indices
|
|
static int_list make_best_fan( const triele_list& master_tris,
|
|
const int center, const int_list& local_tris )
|
|
{
|
|
int_list best_result;
|
|
|
|
// try starting with local triangle to find the best fan arrangement
|
|
for ( int start = 0; start < (int)local_tris.size(); ++start ) {
|
|
cout << "trying with first triangle = " << local_tris[start] << endl;
|
|
|
|
int_list tmp_result;
|
|
tmp_result.clear();
|
|
|
|
FGTriEle current_tri;
|
|
FGTriEle test;
|
|
current_tri = canonify( master_tris[local_tris[start]], center );
|
|
tmp_result.push_back( local_tris[start] );
|
|
|
|
// follow the ring
|
|
int next = -1;
|
|
bool matches = true;
|
|
while ( (next != start) && matches ) {
|
|
// find next triangle in ring
|
|
matches = false;
|
|
for ( int i = 0; i < (int)local_tris.size(); ++i ) {
|
|
test = canonify( master_tris[local_tris[i]], center );
|
|
if ( current_tri.get_n3() == test.get_n2() ) {
|
|
if ( i != start ) {
|
|
cout << " next triangle = " << local_tris[i] << endl;
|
|
current_tri = test;
|
|
tmp_result.push_back( local_tris[i] );
|
|
matches = true;
|
|
next = i;
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
if ( tmp_result.size() == local_tris.size() ) {
|
|
// we found a complete usage, no need to go on
|
|
cout << "we found a complete usage, no need to go on" << endl;
|
|
best_result = tmp_result;
|
|
break;
|
|
} else if ( tmp_result.size() > best_result.size() ) {
|
|
// we found a better way to fan
|
|
cout << "we found a better fan arrangement" << endl;
|
|
best_result = tmp_result;
|
|
}
|
|
}
|
|
|
|
return best_result;
|
|
}
|
|
|
|
|
|
static bool in_fan(int index, const int_list& fan ) {
|
|
const_int_list_iterator current = fan.begin();
|
|
const_int_list_iterator last = fan.end();
|
|
|
|
for ( ; current != last; ++current ) {
|
|
if ( index == *current ) {
|
|
return true;
|
|
}
|
|
}
|
|
|
|
return false;
|
|
}
|
|
|
|
|
|
// recursive build fans from triangle list
|
|
fan_list FGGenFans::greedy_build( triele_list tris ) {
|
|
cout << "starting greedy build of fans" << endl;
|
|
|
|
fans.clear();
|
|
|
|
while ( ! tris.empty() ) {
|
|
reverse_list by_node;
|
|
by_node.clear();
|
|
|
|
// traverse the triangle list and for each node, build a list of
|
|
// triangles that attach to it.
|
|
|
|
for ( int i = 0; i < (int)tris.size(); ++i ) {
|
|
int n1 = tris[i].get_n1();
|
|
int n2 = tris[i].get_n2();
|
|
int n3 = tris[i].get_n3();
|
|
|
|
add_and_expand( by_node, n1, i );
|
|
add_and_expand( by_node, n2, i );
|
|
add_and_expand( by_node, n3, i );
|
|
}
|
|
|
|
// find the node in the tris list that attaches to the most
|
|
// triangles
|
|
|
|
int_list biggest_group;
|
|
reverse_list_iterator r_current = by_node.begin();
|
|
reverse_list_iterator r_last = by_node.end();
|
|
int index = 0;
|
|
int counter = 0;
|
|
for ( ; r_current != r_last; ++r_current ) {
|
|
if ( r_current->size() > biggest_group.size() ) {
|
|
biggest_group = *r_current;
|
|
index = counter;
|
|
}
|
|
++counter;
|
|
}
|
|
cout << "triangle pool = " << tris.size() << endl;
|
|
cout << "biggest_group = " << biggest_group.size() << endl;
|
|
cout << "center node = " << index << endl;
|
|
|
|
// make the best fan we can out of this group
|
|
int_list best_fan = make_best_fan( tris, index, biggest_group );
|
|
|
|
// generate point form of best_fan
|
|
int_list node_list;
|
|
node_list.clear();
|
|
|
|
int_list_iterator i_start = best_fan.begin();
|
|
int_list_iterator i_current = i_start;
|
|
int_list_iterator i_last = best_fan.end();
|
|
for ( ; i_current != i_last; ++i_current ) {
|
|
FGTriEle t = canonify( tris[*i_current], index );
|
|
if ( i_start == i_current ) {
|
|
node_list.push_back( t.get_n1() );
|
|
node_list.push_back( t.get_n2() );
|
|
}
|
|
node_list.push_back( t.get_n3() );
|
|
}
|
|
cout << "best list size = " << node_list.size() << endl;
|
|
|
|
// add this fan to the fan list
|
|
fans.push_back( node_list );
|
|
|
|
// delete the triangles in best_fan out of tris and repeat
|
|
triele_list_iterator t_current = tris.begin();
|
|
triele_list_iterator t_last = tris.end();
|
|
counter = 0;
|
|
for ( ; t_current != t_last; ++t_current ) {
|
|
if ( in_fan(counter, best_fan) ) {
|
|
cout << "erasing " << counter << " from master tri pool"
|
|
<< endl;
|
|
tris.erase( t_current );
|
|
}
|
|
++counter;
|
|
}
|
|
}
|
|
|
|
cout << "end of greedy build of fans" << endl;
|
|
cout << "average fan size = " << ave_size() << endl;
|
|
|
|
return fans;
|
|
}
|
|
|
|
|
|
// report average fan size
|
|
double FGGenFans::ave_size() {
|
|
double sum;
|
|
|
|
fan_list_iterator current = fans.begin();
|
|
fan_list_iterator last = fans.end();
|
|
for ( ; current != last; ++current ) {
|
|
sum += current->size();
|
|
}
|
|
|
|
return sum / (double)fans.size();
|
|
}
|
|
|
|
|
|
// $Log$
|
|
// Revision 1.2 1999/03/30 23:50:15 curt
|
|
// Fannifier is clearly bugging ... working on debugging it. I suspect there
|
|
// is a problem related to deleting triangles from the triangle pool as they
|
|
// are combined into fans.
|
|
//
|
|
// Revision 1.1 1999/03/29 13:08:35 curt
|
|
// Initial revision.
|
|
//
|