Rewrite the line to polygon making routine to (hopefully) make the
line widths consistant and accurate always.
This commit is contained in:
curt
parent
1a741df940
commit
e6c1dc4c0c
2 changed files with 123 additions and 68 deletions
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@ -26,10 +26,11 @@ getIntersection (const Point3D &p0, const Point3D &p1,
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((p3.y()-p2.y())*(p1.x()-p0.x()))-((p3.x()-p2.x())*(p1.y()-p0.y()));
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((p3.y()-p2.y())*(p1.x()-p0.x()))-((p3.x()-p2.x())*(p1.y()-p0.y()));
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if (u_den == 0) {
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if (u_den == 0) {
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if (u_num == 0)
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if (u_num == 0) {
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SG_LOG(SG_GENERAL, SG_ALERT, "Intersection: coincident lines");
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SG_LOG(SG_GENERAL, SG_ALERT, "Intersection: coincident lines");
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else
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} else {
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SG_LOG(SG_GENERAL, SG_ALERT, "Intersection: parallel lines");
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SG_LOG(SG_GENERAL, SG_ALERT, "Intersection: parallel lines");
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}
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return false;
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return false;
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} else {
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} else {
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double u = u_num/u_den;
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double u = u_num/u_den;
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@ -72,78 +73,128 @@ makePolygon (const Point3D &p, int width, TGPolygon &polygon)
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}
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}
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// Alternate makePolygon from a line routine
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void
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void
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makePolygon (const Line &line, int width, TGPolygon &polygon)
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makePolygon (const Line &line, int width, TGPolygon &polygon)
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{
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{
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vector<TGPolygon> segment_list;
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point_list left_side, right_side;
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left_side.clear();
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right_side.clear();
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Point3D p0, p1, p2;
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double a1, a2, dist;
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double angle0, angle1;
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double x, y, az1;
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int i;
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// prime the pump
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p0 = line.getPoint(0);
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p1 = line.getPoint(1);
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int nPoints = line.getPointCount();
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// calculate heading of first line
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int i;
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geo_inverse_wgs_84(0, p0.y(), p0.x(), p1.y(), p1.x(),
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for (i = 0; i < nPoints - 1; i++) {
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&a1, &a2, &dist);
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const Point3D p1 = line.getPoint(i);
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angle0 = (a1 + a2) / 2.0;
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const Point3D p2 = line.getPoint(i+1);
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// calculate right offset edge for line
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geo_direct_wgs_84(0, p0.y(), p0.x(),
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CLAMP_ANGLE(angle0+90), width/2, &y, &x, &az1);
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right_side.push_back( Point3D( x, y, 0 ) );
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double angle1, angle2, dist, x, y, az;
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// calculate left offset edge for line
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geo_direct_wgs_84(0, p0.y(), p0.x(),
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geo_inverse_wgs_84(0, p1.y(), p1.x(), p2.y(), p2.x(), &angle1, &angle2, &dist);
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CLAMP_ANGLE(angle0-90), width/2, &y, &x, &az1);
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left_side.push_back( Point3D( x, y, 0 ) );
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int nPoints = line.getPointCount();
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for ( i = 0; i < nPoints - 2; i++ ) {
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p0 = line.getPoint(i);
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p1 = line.getPoint(i+1);
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p2 = line.getPoint(i+2);
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// calculate heading of line0
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geo_inverse_wgs_84(0, p0.y(), p0.x(), p1.y(), p1.x(),
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&a1, &a2, &dist);
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angle0 = (a1 + a2) / 2.0;
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// calculate heading of line1
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geo_inverse_wgs_84(0, p1.y(), p1.x(), p2.y(), p2.x(),
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&a1, &a2, &dist);
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angle1 = (a1 + a2) / 2.0;
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// calculate right offset edge for line0
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geo_direct_wgs_84(0, p0.y(), p0.x(),
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CLAMP_ANGLE(angle0+90), width/2, &y, &x, &az1);
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Point3D roff0( x, y, 0 );
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geo_direct_wgs_84(0, p1.y(), p1.x(),
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CLAMP_ANGLE(angle0+90), width/2, &y, &x, &az1);
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Point3D roff1( x, y, 0 );
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// calculate left offset edge for line0
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geo_direct_wgs_84(0, p0.y(), p0.x(),
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CLAMP_ANGLE(angle0-90), width/2, &y, &x, &az1);
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Point3D loff0( x, y, 0 );
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geo_direct_wgs_84(0, p1.y(), p1.x(),
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CLAMP_ANGLE(angle0-90), width/2, &y, &x, &az1);
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Point3D loff1( x, y, 0 );
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// calculate right offset edge for line1
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geo_direct_wgs_84(0, p1.y(), p1.x(),
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CLAMP_ANGLE(angle1+90), width/2, &y, &x, &az1);
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Point3D roff2( x, y, 0 );
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geo_direct_wgs_84(0, p2.y(), p2.x(),
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CLAMP_ANGLE(angle1+90), width/2, &y, &x, &az1);
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Point3D roff3( x, y, 0 );
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// calculate left offset edge for line1
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geo_direct_wgs_84(0, p1.y(), p1.x(),
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CLAMP_ANGLE(angle1-90), width/2, &y, &x, &az1);
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Point3D loff2( x, y, 0 );
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geo_direct_wgs_84(0, p2.y(), p2.x(),
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CLAMP_ANGLE(angle1-90), width/2, &y, &x, &az1);
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Point3D loff3( x, y, 0 );
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// calculate intersection of roffset line1 and right offset line2
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Point3D rint, lint;
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if ( !getIntersection( roff0, roff1, roff2, roff3, rint ) ) {
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// intersection failed, use the average of roff1 and roff2
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rint = ( roff1 + roff2 ) / 2.0;
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}
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right_side.push_back( rint );
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if ( !getIntersection( loff0, loff1, loff2, loff3, lint ) ) {
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// intersection failed, use the average of roff1 and roff2
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lint = ( loff1 + loff2 ) / 2.0;
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}
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left_side.push_back( lint );
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}
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// finish the end of the polyline
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p0 = line.getPoint(nPoints - 2);
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p1 = line.getPoint(nPoints - 1);
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// calculate heading of last line
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geo_inverse_wgs_84(0, p0.y(), p0.x(), p1.y(), p1.x(),
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&a1, &a2, &dist);
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angle0 = (a1 + a2) / 2.0;
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// calculate right offset edge for line
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geo_direct_wgs_84(0, p1.y(), p1.x(),
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CLAMP_ANGLE(angle0+90), width/2, &y, &x, &az1);
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right_side.push_back( Point3D(x, y, 0) );
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// calculate left offset edge for line
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geo_direct_wgs_84(0, p1.y(), p1.x(),
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CLAMP_ANGLE(angle0-90), width/2, &y, &x, &az1);
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left_side.push_back( Point3D(x, y, 0) );
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// Finally assemble the polygon with counter clockwise winding
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polygon.erase();
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polygon.erase();
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for ( i = 0; i < (int)right_side.size(); ++i ) {
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// Wind each rectangle counterclockwise
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polygon.add_node( 0, right_side[i] );
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}
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// Corner 1
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for ( i = left_side.size() - 1; i >= 0; --i ) {
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geo_direct_wgs_84(0, p1.y(), p1.x(), CLAMP_ANGLE(angle1+90), width/2, &y, &x, &az);
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polygon.add_node( 0, left_side[i] );
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polygon.add_node(0, Point3D(x, y, 0));
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}
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// Corner 2
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geo_direct_wgs_84(0, p2.y(), p2.x(), CLAMP_ANGLE(angle1+90), width/2, &y, &x, &az);
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polygon.add_node(0, Point3D(x, y, 0));
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// Corner 3
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geo_direct_wgs_84(0, p2.y(), p2.x(), CLAMP_ANGLE(angle1-90), width/2, &y, &x, &az);
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polygon.add_node(0, Point3D(x, y, 0));
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// Corner 4
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geo_direct_wgs_84(0, p1.y(), p1.x(), CLAMP_ANGLE(angle1-90), width/2, &y, &x, &az);
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polygon.add_node(0, Point3D(x, y, 0));
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// Save this rectangle
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segment_list.push_back(polygon);
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}
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// Build one big polygon out of all the rectangles by intersecting
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// the lines running through the bottom and top sides
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polygon.erase();
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// Connect the bottom part.
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int nSegments = segment_list.size();
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Point3D intersection;
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polygon.add_node(0, segment_list[0].get_pt(0, 0));
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for (i = 0; i < nSegments - 1; i++) {
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if (getIntersection(segment_list[i].get_pt(0, 0),
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segment_list[i].get_pt(0, 1),
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segment_list[i+1].get_pt(0, 0),
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segment_list[i+1].get_pt(0, 1),
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intersection))
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polygon.add_node(0, intersection);
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else
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polygon.add_node(0, segment_list[i].get_pt(0, 1));
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}
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polygon.add_node(0, segment_list[nSegments-1].get_pt(0, 1));
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// Connect the top part
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polygon.add_node(0, segment_list[nSegments-1].get_pt(0, 2));
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for (i = nSegments - 1; i > 0; i--) {
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if (getIntersection(segment_list[i].get_pt(0, 2),
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segment_list[i].get_pt(0, 3),
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segment_list[i-1].get_pt(0, 2),
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segment_list[i-1].get_pt(0, 3),
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intersection))
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polygon.add_node(0, intersection);
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else
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polygon.add_node(0, segment_list[i].get_pt(0, 3));
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}
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polygon.add_node(0, segment_list[0].get_pt(0, 3));
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}
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}
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@ -82,6 +82,10 @@ void makePolygon (const Point3D &p, int width, TGPolygon &polygon);
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* a single point at y=90 and y=-90. As a result, this function
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* a single point at y=90 and y=-90. As a result, this function
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* uses the WGS80 functions, rather than simple Pythagorean stuff.
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* uses the WGS80 functions, rather than simple Pythagorean stuff.
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*
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*
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* Update CLO 7 Mar 2003: Function rewritten to carefully preserve
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* specifed polygon width through any kind of point to point angle
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* change.
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*
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* @param line The multi-segment line inside the new polygon.
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* @param line The multi-segment line inside the new polygon.
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* @param width The width in standard units (meters for FlightGear).
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* @param width The width in standard units (meters for FlightGear).
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* @param polygon The object that will hold the new polygon.
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* @param polygon The object that will hold the new polygon.
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