Mercurial > dive4elements > river
changeset 1799:281b9430c720
Polygon2D: More code to build polygons from curve.
flys-artifacts/trunk@3123 c6561f87-3c4e-4783-a992-168aeb5c3f6f
| author | Sascha L. Teichmann <sascha.teichmann@intevation.de> |
|---|---|
| date | Mon, 31 Oct 2011 15:54:02 +0000 |
| parents | 552888e9c64a |
| children | 1402991208d5 |
| files | flys-artifacts/ChangeLog flys-artifacts/src/main/java/de/intevation/flys/artifacts/geom/Polygon2D.java flys-artifacts/src/main/java/de/intevation/flys/artifacts/geom/VectorUtils.java |
| diffstat | 3 files changed, 123 insertions(+), 15 deletions(-) [+] |
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--- a/flys-artifacts/ChangeLog Mon Oct 31 11:32:11 2011 +0000 +++ b/flys-artifacts/ChangeLog Mon Oct 31 15:54:02 2011 +0000 @@ -1,3 +1,11 @@ +2011-10-31 Sascha L. Teichmann <sascha.teichmann@intevation.de> + + * src/main/java/de/intevation/flys/artifacts/geom/VectorUtils.java: + Made X() and Y() access macros public. + + * src/main/java/de/intevation/flys/artifacts/geom/Polygon2D.java: + More code. WIP. + 2011-10-31 Sascha L. Teichmann <sascha.teichmann@intevation.de> * src/main/java/de/intevation/flys/artifacts/geom/Polygon2D.java:
--- a/flys-artifacts/src/main/java/de/intevation/flys/artifacts/geom/Polygon2D.java Mon Oct 31 11:32:11 2011 +0000 +++ b/flys-artifacts/src/main/java/de/intevation/flys/artifacts/geom/Polygon2D.java Mon Oct 31 15:54:02 2011 +0000 @@ -15,17 +15,13 @@ import de.intevation.flys.artifacts.math.Linear; +import static de.intevation.flys.geom.VectorUtils.X; +import static de.intevation.flys.geom.VectorUtils.Y; +import static de.intevation.flys.geom.VectorUtils.EPSILON; + public class Polygon2D implements Serializable { - private static final double X(Point2D p) { - return p.getX(); - } - - private static final double Y(Point2D p) { - return p.getY(); - } - public static final Comparator<Point2D> POINT_X_CMP = new Comparator<Point2D>() { public int compare(Point2D a, Point2D b) { @@ -52,6 +48,10 @@ points = new ArrayList<Point2D>(); } + public Point2D(List<Point2D> points) { + this.points = points; + } + public void add(double x, double y) { points.add(new Point2D.Double(x, y)); } @@ -197,8 +197,10 @@ double ax = X(as[0]); double bx = X(bs[0]); - int ai = 0; - int bi = 0; + int ai = 1; + int bi = 1; + + boolean intersect = false; if (ax == bx) { apoints.add(as[0]); @@ -206,13 +208,13 @@ } else if (ax > bx) { apoints.add(as[0]); - bi = 1; // exists because of overlap double bx1; while ((bx1 = X(bs[bi])) < ax) ++bi; if (bx1 == ax) { bpoints.add(bs[bi]); } else { // need to calculate start b point. + intersect = true; double by1 = Linear.linear( ax, X(bs[bi-1]), bx1, @@ -223,13 +225,13 @@ } else { // bx > ax: Symmetric case bpoints.add(bs[0]); - ai = 1; // exists because of overlap double ax1; while ((ax1 = X(as[ai])) < bx) ++ai; if (ax1 == bx) { apoints.add(as[ai]); } else { // need to calculate start b point. + intersect = true; double ay1 = Linear.linear( bx, X(as[ai-1]), ax1, @@ -242,7 +244,105 @@ // now we have a point in each list, decide if neg/pos. boolean neg = Y(bpoints.get(0)) > Y(apoints.get(0)); - // TODO: Continue with inner points + // Continue with inner points + + Line line = new Line(); + + while (ai < as.length && bi < bs.length) { + double xan = X(as[ai]); + double xbn = X(bs[bi]); + if (xan == xbn) { + double yan = Y(as[ai]); + double ybn = Y(bs[ai]); + + if (neg) { + if (yan > ybn) { // intersection + // TODO: calculate intersection point + // finish polygon and start a new one + } + else { // no intersection + addCheck(as[ai], apoints); + addCheck(bs[bi], bpoints); + ++ai; + ++bi; + } + } + else { // not neg + if (ybn > yan) { // intersection + // TODO: calculate intersection point + // finish polygon and start a new one + } + else { // no intersection + addCheck(as[ai], apoints); + addCheck(bs[bi], bpoints); + ++ai; + ++bi; + } + } + } + else if (xan > xbn) { + line.set(apoints.get(apoints.size()-1), as[ai]); + double dir = neg ? -1d: 1d; // XXX: correct sign? + while (bi < bs.length + && X(bs[bi]) < xan + && line.eval(bs[bi])*dir > EPSILON) + ++bi; + if (bi == bs.length) { + // b run out of points + // calculate Y(last_a, as[ai]) for X(bs[bi-1]) + double ay1 = Linear.linear( + X(bs[bi-1]), + X(apoints.get(apoints.size()-1)), X(as[ai]), + Y(apoints.get(apoints.size()-1)), Y(as[ai])); + addCheck(new Point2D.Double(X(bs[bi-1]), ay1), apoints); + addCheck(bs[bi-1], bpoints); + break; + } + else { + // TODO: intersect line and/or X(bs[bi]) >= xan? + } + } + else { // xbn > xan + line.set(bpoints.get(bpoints.size()-1), bs[bi]); + // TODO: continue symmetric + } + } + + // TODO: Continue with closing segment + } + + public static final class Line { + + private double a; + private double b; + private double c; + + public Line() { + } + + public Line(Point2D p1, Point2D p2) { + set(p1, p2); + } + + public void set(Point2D p1, Point2D p2) { + Point2D p3 = + VectorUtils.normalize( + VectorUtils.sub(p1, p2)); + + Point2D n = VectorUtils.ortho(p3); + + a = X(n); + b = Y(n); + + // a*x + b*y + c = 0 + // c = -a*x -b*y + + c = -a*X(p1) - b*Y(p1); + } + + public double eval(Point2D p) { + return a*X(p) + b*Y(p) + c; + } } public static void createPolygons(
--- a/flys-artifacts/src/main/java/de/intevation/flys/artifacts/geom/VectorUtils.java Mon Oct 31 11:32:11 2011 +0000 +++ b/flys-artifacts/src/main/java/de/intevation/flys/artifacts/geom/VectorUtils.java Mon Oct 31 15:54:02 2011 +0000 @@ -9,11 +9,11 @@ private VectorUtils() { } - private static final double X(Point2D p) { + public static final double X(Point2D p) { return p.getX(); } - private static final double Y(Point2D p) { + public static final double Y(Point2D p) { return p.getY(); }