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Support creation of polygon lines with non-integer widths. For instance,

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road line markings in the USA typically are 4 inches wide (about 10cm).
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curt 2007-11-05 14:00:23 +00:00
parent 594c1ffa64
commit fbdbcb076b
2 changed files with 57 additions and 52 deletions
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105
src/Lib/Geometry/util.cxx
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@ -24,28 +24,28 @@ getIntersection (const Point3D &p0, const Point3D &p1,
const Point3D &p2, const Point3D &p3, const Point3D &p2, const Point3D &p3,
Point3D &intersection) Point3D &intersection)
{ {
const double my_eps = 0.00000000000001; const double my_eps = 0.00000000000001;
double u_num =
((p3.x()-p2.x())*(p0.y()-p2.y()))-((p3.y()-p2.y())*(p0.x()-p2.x()));
double u_den =
((p3.y()-p2.y())*(p1.x()-p0.x()))-((p3.x()-p2.x())*(p1.y()-p0.y()));
double u_num = if ( fabs(u_den) < my_eps ) {
((p3.x()-p2.x())*(p0.y()-p2.y()))-((p3.y()-p2.y())*(p0.x()-p2.x())); if ( fabs(u_num) < my_eps ) {
double u_den = SG_LOG(SG_GENERAL, SG_ALERT, "Intersection: coincident lines");
((p3.y()-p2.y())*(p1.x()-p0.x()))-((p3.x()-p2.x())*(p1.y()-p0.y())); } else {
SG_LOG(SG_GENERAL, SG_ALERT, "Intersection: parallel lines");
if ( fabs(u_den) < my_eps ) { }
if ( fabs(u_num) < my_eps ) { return false;
SG_LOG(SG_GENERAL, SG_ALERT, "Intersection: coincident lines");
} else { } else {
SG_LOG(SG_GENERAL, SG_ALERT, "Intersection: parallel lines"); double u = u_num/u_den;
// cout << "u = " << u << " u_num = " << u_num << " u_den = " << u_den << endl;
intersection = Point3D((p0.x()+u*(p1.x()-p0.x())),
(p0.y()+u*(p1.y()-p0.y())),
0);
return true;
} }
return false;
} else {
double u = u_num/u_den;
// cout << "u = " << u << " u_num = " << u_num << " u_den = " << u_den << endl;
intersection = Point3D((p0.x()+u*(p1.x()-p0.x())),
(p0.y()+u*(p1.y()-p0.y())),
0);
return true;
}
} }
@ -59,7 +59,7 @@ getIntersection (const Point3D &p0, const Point3D &p1,
* uses the WGS80 functions, rather than simple Pythagorean stuff. * uses the WGS80 functions, rather than simple Pythagorean stuff.
*/ */
void void
makePolygon (const Point3D &p, int width, TGPolygon &polygon) makePolygon (const Point3D &p, double width, TGPolygon &polygon)
{ {
double x, y, az; double x, y, az;
double lon = p.x(); double lon = p.x();
@ -67,21 +67,23 @@ makePolygon (const Point3D &p, int width, TGPolygon &polygon)
polygon.erase(); polygon.erase();
geo_direct_wgs_84(0, lat, lon, 90, width/2, &y, &x, &az); geo_direct_wgs_84(0, lat, lon, 90, width/2.0, &y, &x, &az);
double dlon = x - lon; double dlon = x - lon;
geo_direct_wgs_84(0, lat, lon, 0, width/2, &y, &x, &az); geo_direct_wgs_84(0, lat, lon, 0, width/2.0, &y, &x, &az);
double dlat = y - lat; double dlat = y - lat;
polygon.add_node(0, Point3D(lon - dlon, lat - dlat, 0)); polygon.add_node(0, Point3D(lon - dlon, lat - dlat, 0));
polygon.add_node(0, Point3D(lon + dlon, lat - dlat, 0)); polygon.add_node(0, Point3D(lon + dlon, lat - dlat, 0));
polygon.add_node(0, Point3D(lon + dlon, lat + dlat, 0)); polygon.add_node(0, Point3D(lon + dlon, lat + dlat, 0));
polygon.add_node(0, Point3D(lon - dlon, lat + dlat, 0)); polygon.add_node(0, Point3D(lon - dlon, lat + dlat, 0));
polygon.set_hole_flag(0, 0); // mark as solid
} }
void void
makePolygon (const Line &line, int width, TGPolygon &polygon) makePolygon (const Line &line, double width, TGPolygon &polygon)
{ {
vector<TGPolygon> segment_list; vector<TGPolygon> segment_list;
@ -100,7 +102,7 @@ makePolygon (const Line &line, int width, TGPolygon &polygon)
// Corner 1 // Corner 1
// cout << "point = " << i << endl; // cout << "point = " << i << endl;
geo_direct_wgs_84(0, p1.y(), p1.x(), CLAMP_ANGLE(angle1+90), width/2, &y, &x, &az); geo_direct_wgs_84(0, p1.y(), p1.x(), CLAMP_ANGLE(angle1+90), width/2.0, &y, &x, &az);
// Sometimes creating the new point can wrap the date line, even if the // Sometimes creating the new point can wrap the date line, even if the
// original line does not. This can cause problems later, so lets just // original line does not. This can cause problems later, so lets just
// clip the result to date line and hope that the typical error is very // clip the result to date line and hope that the typical error is very
@ -113,7 +115,7 @@ makePolygon (const Line &line, int width, TGPolygon &polygon)
// cout << "corner 1 = " << Point3D(x, y, 0) << endl; // cout << "corner 1 = " << Point3D(x, y, 0) << endl;
// Corner 2 // Corner 2
geo_direct_wgs_84(0, p2.y(), p2.x(), CLAMP_ANGLE(angle1+90), width/2, &y, &x, &az); geo_direct_wgs_84(0, p2.y(), p2.x(), CLAMP_ANGLE(angle1+90), width/2.0, &y, &x, &az);
// Sometimes creating the new point can wrap the date line, even if the // Sometimes creating the new point can wrap the date line, even if the
// original line does not. This can cause problems later, so lets just // original line does not. This can cause problems later, so lets just
// clip the result to date line and hope that the typical error is very // clip the result to date line and hope that the typical error is very
@ -126,7 +128,7 @@ makePolygon (const Line &line, int width, TGPolygon &polygon)
// cout << "corner 2 = " << Point3D(x, y, 0) << endl; // cout << "corner 2 = " << Point3D(x, y, 0) << endl;
// Corner 3 // Corner 3
geo_direct_wgs_84(0, p2.y(), p2.x(), CLAMP_ANGLE(angle1-90), width/2, &y, &x, &az); geo_direct_wgs_84(0, p2.y(), p2.x(), CLAMP_ANGLE(angle1-90), width/2.0, &y, &x, &az);
// Sometimes creating the new point can wrap the date line, even if the // Sometimes creating the new point can wrap the date line, even if the
// original line does not. This can cause problems later, so lets just // original line does not. This can cause problems later, so lets just
// clip the result to date line and hope that the typical error is very // clip the result to date line and hope that the typical error is very
@ -139,7 +141,7 @@ makePolygon (const Line &line, int width, TGPolygon &polygon)
// cout << "corner 3 = " << Point3D(x, y, 0) << endl; // cout << "corner 3 = " << Point3D(x, y, 0) << endl;
// Corner 4 // Corner 4
geo_direct_wgs_84(0, p1.y(), p1.x(), CLAMP_ANGLE(angle1-90), width/2, &y, &x, &az); geo_direct_wgs_84(0, p1.y(), p1.x(), CLAMP_ANGLE(angle1-90), width/2.0, &y, &x, &az);
// Sometimes creating the new point can wrap the date line, even if the // Sometimes creating the new point can wrap the date line, even if the
// original line does not. This can cause problems later, so lets just // original line does not. This can cause problems later, so lets just
// clip the result to date line and hope that the typical error is very // clip the result to date line and hope that the typical error is very
@ -166,18 +168,18 @@ makePolygon (const Line &line, int width, TGPolygon &polygon)
polygon.add_node(0, segment_list[0].get_pt(0, 0)); polygon.add_node(0, segment_list[0].get_pt(0, 0));
// cout << "bnode = " << segment_list[0].get_pt(0, 0) << endl; // cout << "bnode = " << segment_list[0].get_pt(0, 0) << endl;
for (i = 0; i < nSegments - 1; i++) { for (i = 0; i < nSegments - 1; i++) {
// cout << "point = " << i << endl; // cout << "point = " << i << endl;
if (getIntersection(segment_list[i].get_pt(0, 0), if (getIntersection(segment_list[i].get_pt(0, 0),
segment_list[i].get_pt(0, 1), segment_list[i].get_pt(0, 1),
segment_list[i+1].get_pt(0, 0), segment_list[i+1].get_pt(0, 0),
segment_list[i+1].get_pt(0, 1), segment_list[i+1].get_pt(0, 1),
intersection)) { intersection)) {
polygon.add_node(0, intersection); polygon.add_node(0, intersection);
// cout << "bnode (int) = " << intersection << endl; // cout << "bnode (int) = " << intersection << endl;
} else { } else {
polygon.add_node(0, segment_list[i].get_pt(0, 1)); polygon.add_node(0, segment_list[i].get_pt(0, 1));
// cout << "bnode = " << segment_list[i].get_pt(0, 1) << endl; // cout << "bnode = " << segment_list[i].get_pt(0, 1) << endl;
} }
} }
polygon.add_node(0, segment_list[nSegments-1].get_pt(0, 1)); polygon.add_node(0, segment_list[nSegments-1].get_pt(0, 1));
// cout << "bnode = " << segment_list[nSegments-1].get_pt(0, 1) << endl; // cout << "bnode = " << segment_list[nSegments-1].get_pt(0, 1) << endl;
@ -186,20 +188,23 @@ makePolygon (const Line &line, int width, TGPolygon &polygon)
polygon.add_node(0, segment_list[nSegments-1].get_pt(0, 2)); polygon.add_node(0, segment_list[nSegments-1].get_pt(0, 2));
// cout << "tnode = " << segment_list[nSegments-1].get_pt(0, 2) << endl; // cout << "tnode = " << segment_list[nSegments-1].get_pt(0, 2) << endl;
for (i = nSegments - 1; i > 0; i--) { for (i = nSegments - 1; i > 0; i--) {
if (getIntersection(segment_list[i].get_pt(0, 2), // cout << "point = " << i << endl;
segment_list[i].get_pt(0, 3), if (getIntersection(segment_list[i].get_pt(0, 2),
segment_list[i-1].get_pt(0, 2), segment_list[i].get_pt(0, 3),
segment_list[i-1].get_pt(0, 3), segment_list[i-1].get_pt(0, 2),
intersection)) { segment_list[i-1].get_pt(0, 3),
polygon.add_node(0, intersection); intersection)) {
// cout << "tnode (int) = " << intersection << endl; polygon.add_node(0, intersection);
} else { // cout << "tnode (int) = " << intersection << endl;
polygon.add_node(0, segment_list[i].get_pt(0, 3)); } else {
// cout << "tnode = " << segment_list[i].get_pt(0, 3) << endl; polygon.add_node(0, segment_list[i].get_pt(0, 3));
} // cout << "tnode = " << segment_list[i].get_pt(0, 3) << endl;
}
} }
polygon.add_node(0, segment_list[0].get_pt(0, 3)); polygon.add_node(0, segment_list[0].get_pt(0, 3));
// cout << "tnode = " << segment_list[0].get_pt(0, 3) << endl; // cout << "tnode = " << segment_list[0].get_pt(0, 3) << endl;
polygon.set_hole_flag(0, 0); // mark as solid
} }

4
src/Lib/Geometry/util.hxx
View file

@ -70,7 +70,7 @@ bool getIntersection (const Point3D &p0, const Point3D &p1,
* @param width The width in standard units (meters for FlightGear). * @param width The width in standard units (meters for FlightGear).
* @param polygon The object that will hold the new polygon. * @param polygon The object that will hold the new polygon.
*/ */
void makePolygon (const Point3D &p, int width, TGPolygon &polygon); void makePolygon (const Point3D &p, double width, TGPolygon &polygon);
/** /**
@ -90,7 +90,7 @@ void makePolygon (const Point3D &p, int width, TGPolygon &polygon);
* @param width The width in standard units (meters for FlightGear). * @param width The width in standard units (meters for FlightGear).
* @param polygon The object that will hold the new polygon. * @param polygon The object that will hold the new polygon.
*/ */
void makePolygon (const Line &line, int width, TGPolygon &polygon); void makePolygon (const Line &line, double width, TGPolygon &polygon);
/** /**