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flightgear/Tools/Construct/GenOutput/genobj.cxx
curt c062fe49c4 Start of support for precalculating texture coordinates.
Try to avoid a situation where you cycle between too many nodes and two few
  nodes with just a single increment of error level.
1999-05-12 02:09:02 +00:00

376 lines
10 KiB
C++

// genobj.hxx -- Generate the flight gear "obj" file format from the
// triangle output
//
// 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.
//
// $Id$
#include <time.h>
#include <Polygon/names.hxx>
#include <Tools/scenery_version.hxx>
#include "genobj.hxx"
// calculate the global bounding sphere. Center is the average of the
// points.
void FGGenOutput::calc_gbs( FGConstruct& c ) {
double dist_squared;
double radius_squared = 0;
gbs_center = Point3D( 0.0 );
point_list wgs84_nodes = c.get_wgs84_nodes();
const_point_list_iterator current = wgs84_nodes.begin();
const_point_list_iterator last = wgs84_nodes.end();
for ( ; current != last; ++current ) {
gbs_center += *current;
}
gbs_center /= wgs84_nodes.size();
current = wgs84_nodes.begin();
for ( ; current != last; ++current ) {
dist_squared = gbs_center.distance3Dsquared(*current);
if ( dist_squared > radius_squared ) {
radius_squared = dist_squared;
}
}
gbs_radius = sqrt(radius_squared);
}
#define FG_TEX_CONSTANT 69.0
// traverse the specified fan and attempt to calculate "none
// stretching" texture coordinates
int_list FGGenOutput::calc_tex_coords( point_list geod_nodes, int_list fan ) {
// cout << "calculating texture coordinates for a specific fan of size = "
// << fan.size() << endl;
// find min/max of fan
Point3D min, max, p, t;
bool first = true;
for ( int i = 0; i < (int)fan.size(); ++i ) {
p = geod_nodes[ fan[i] ];
t.setx( p.x() * FG_TEX_CONSTANT );
t.sety( p.y() * FG_TEX_CONSTANT );
if ( first ) {
min = max = t;
first = false;
} else {
if ( t.x() < min.x() ) {
min.setx( t.x() );
}
if ( t.y() < min.y() ) {
min.sety( t.y() );
}
if ( t.x() > max.x() ) {
max.setx( t.x() );
}
if ( t.y() > max.y() ) {
max.sety( t.y() );
}
}
}
min.setx( (double)( (int)min.x() - 1 ) );
min.sety( (double)( (int)min.y() - 1 ) );
// cout << "found min = " << min << endl;
// generate tex_list
Point3D shifted_t;
int index;
int_list tex;
tex.clear();
for ( int i = 0; i < (int)fan.size(); ++i ) {
p = geod_nodes[ fan[i] ];
t.setx( p.x() * FG_TEX_CONSTANT );
t.sety( p.y() * FG_TEX_CONSTANT );
shifted_t = t - min;
if ( shifted_t.x() < FG_EPSILON ) {
shifted_t.setx( 0.0 );
}
if ( shifted_t.y() < FG_EPSILON ) {
shifted_t.sety( 0.0 );
}
shifted_t.setz( 0.0 );
index = tex_coords.unique_add( shifted_t );
tex.push_back( index );
}
return tex;
}
// build the necessary output structures based on the triangulation
// data
int FGGenOutput::build( FGConstruct& c ) {
FGTriNodes trinodes = c.get_tri_nodes();
// copy the geodetic node list into this class
geod_nodes = trinodes.get_node_list();
// copy the triangle list into this class
tri_elements = c.get_tri_elements();
// build the trifan list
cout << "total triangles = " << tri_elements.size() << endl;
FGGenFans f;
for ( int i = 0; i < FG_MAX_AREA_TYPES; ++i ) {
triele_list area_tris;
area_tris.erase( area_tris.begin(), area_tris.end() );
const_triele_list_iterator t_current = tri_elements.begin();
const_triele_list_iterator t_last = tri_elements.end();
for ( ; t_current != t_last; ++t_current ) {
if ( (int)t_current->get_attribute() == i ) {
area_tris.push_back( *t_current );
}
}
if ( (int)area_tris.size() > 0 ) {
cout << "generating fans for area = " << i << endl;
fans[i] = f.greedy_build( area_tris );
}
}
// build the texture coordinate list and make a parallel structure
// to the fan list for pointers into the texture list
cout << "calculating texture coordinates" << endl;
tex_coords.clear();
for ( int i = 0; i < FG_MAX_AREA_TYPES; ++i ) {
for ( int j = 0; j < (int)fans[i].size(); ++j ) {
int_list t_list = calc_tex_coords( geod_nodes, fans[i][j] );
// cout << fans[i][j].size() << " === "
// << t_list.size() << endl;
textures[i].push_back( t_list );
}
}
// calculate the global bounding sphere
calc_gbs( c );
cout << "center = " << gbs_center << " radius = " << gbs_radius << endl;
return 1;
}
// caclulate the bounding sphere for a list of triangle faces
void FGGenOutput::calc_group_bounding_sphere( FGConstruct& c,
const fan_list& fans,
Point3D *center, double *radius )
{
cout << "calculate group bounding sphere for " << fans.size() << " fans."
<< endl;
point_list wgs84_nodes = c.get_wgs84_nodes();
// generate a list of unique points from the triangle list
FGTriNodes nodes;
const_fan_list_iterator f_current = fans.begin();
const_fan_list_iterator f_last = fans.end();
for ( ; f_current != f_last; ++f_current ) {
const_int_list_iterator i_current = f_current->begin();
const_int_list_iterator i_last = f_current->end();
for ( ; i_current != i_last; ++i_current ) {
Point3D p1 = wgs84_nodes[ *i_current ];
nodes.unique_add(p1);
}
}
// find average of point list
*center = Point3D( 0.0 );
point_list points = nodes.get_node_list();
// cout << "found " << points.size() << " unique nodes" << endl;
point_list_iterator p_current = points.begin();
point_list_iterator p_last = points.end();
for ( ; p_current != p_last; ++p_current ) {
*center += *p_current;
}
*center /= points.size();
// find max radius
double dist_squared;
double max_squared = 0;
p_current = points.begin();
p_last = points.end();
for ( ; p_current != p_last; ++p_current ) {
dist_squared = (*center).distance3Dsquared(*p_current);
if ( dist_squared > max_squared ) {
max_squared = dist_squared;
}
}
*radius = sqrt(max_squared);
}
// caclulate the bounding sphere for the specified triangle face
void FGGenOutput::calc_bounding_sphere( FGConstruct& c, const FGTriEle& t,
Point3D *center, double *radius )
{
point_list wgs84_nodes = c.get_wgs84_nodes();
*center = Point3D( 0.0 );
Point3D p1 = wgs84_nodes[ t.get_n1() ];
Point3D p2 = wgs84_nodes[ t.get_n2() ];
Point3D p3 = wgs84_nodes[ t.get_n3() ];
*center = p1 + p2 + p3;
*center /= 3;
double dist_squared;
double max_squared = 0;
dist_squared = (*center).distance3Dsquared(p1);
if ( dist_squared > max_squared ) {
max_squared = dist_squared;
}
dist_squared = (*center).distance3Dsquared(p2);
if ( dist_squared > max_squared ) {
max_squared = dist_squared;
}
dist_squared = (*center).distance3Dsquared(p3);
if ( dist_squared > max_squared ) {
max_squared = dist_squared;
}
*radius = sqrt(max_squared);
}
// write out the fgfs scenery file
int FGGenOutput::write( FGConstruct &c ) {
Point3D p;
string base = c.get_output_base();
FGBucket b = c.get_bucket();
string dir = base + "/Scenery/" + b.gen_base_path();
string command = "mkdir -p " + dir;
system(command.c_str());
string file = dir + "/" + b.gen_index_str();
cout << "Output file = " << file << endl;
FILE *fp;
if ( (fp = fopen( file.c_str(), "w" )) == NULL ) {
cout << "ERROR: opening " << file << " for writing!" << endl;
exit(-1);
}
// write headers
fprintf(fp, "# FGFS Scenery Version %s\n", FG_SCENERY_FILE_FORMAT);
time_t calendar_time = time(NULL);
struct tm *local_tm;
local_tm = localtime( &calendar_time );
char time_str[256];
strftime( time_str, 256, "%a %b %d %H:%M:%S %Z %Y", local_tm);
fprintf(fp, "# Created %s\n", time_str );
fprintf(fp, "\n");
// write global bounding sphere
fprintf(fp, "# gbs %.5f %.5f %.5f %.2f\n",
gbs_center.x(), gbs_center.y(), gbs_center.z(), gbs_radius);
fprintf(fp, "\n");
// write nodes
point_list wgs84_nodes = c.get_wgs84_nodes();
fprintf(fp, "# vertex list\n");
const_point_list_iterator w_current = wgs84_nodes.begin();
const_point_list_iterator w_last = wgs84_nodes.end();
for ( ; w_current != w_last; ++w_current ) {
p = *w_current - gbs_center;
fprintf(fp, "v %.5f %.5f %.5f\n", p.x(), p.y(), p.z());
}
fprintf(fp, "\n");
// write vertex normals
point_list point_normals = c.get_point_normals();
fprintf(fp, "# vertex normal list\n");
const_point_list_iterator n_current = point_normals.begin();
const_point_list_iterator n_last = point_normals.end();
for ( ; n_current != n_last; ++n_current ) {
p = *n_current;
fprintf(fp, "vn %.5f %.5f %.5f\n", p.x(), p.y(), p.z());
}
fprintf(fp, "\n");
// write texture coordinates
point_list tex_coord_list = tex_coords.get_node_list();
for ( int i = 0; i < (int)tex_coord_list.size(); ++i ) {
p = tex_coord_list[i];
fprintf(fp, "vt %.5f %.5f\n", p.x(), p.y());
}
fprintf(fp, "\n");
// write triangles (grouped by type for now)
Point3D center;
double radius;
fprintf(fp, "# triangle groups\n");
fprintf(fp, "\n");
int total_tris = 0;
for ( int i = 0; i < FG_MAX_AREA_TYPES; ++i ) {
if ( (int)fans[i].size() > 0 ) {
string attr_name = get_area_name( (AreaType)i );
calc_group_bounding_sphere( c, fans[i], &center, &radius );
cout << "writing " << (int)fans[i].size() << " fans for "
<< attr_name << endl;
fprintf(fp, "# usemtl %s\n", attr_name.c_str() );
fprintf(fp, "# bs %.4f %.4f %.4f %.2f\n",
center.x(), center.y(), center.z(), radius);
for ( int j = 0; j < (int)fans[i].size(); ++j ) {
fprintf( fp, "tf" );
total_tris += fans[i][j].size() - 2;
for ( int k = 0; k < (int)fans[i][j].size(); ++k ) {
fprintf( fp, " %d/%d", fans[i][j][k], textures[i][j][k] );
}
fprintf( fp, "\n" );
}
fprintf( fp, "\n" );
}
}
cout << "wrote " << total_tris << " tris to output file" << endl;
fclose(fp);
command = "gzip --force --best " + file;
system(command.c_str());
return 1;
}