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geometry: bordermesh: fix region linking to prevent routes that run through unrelated regions

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This commit is contained in:
Torrie Fischer 2021-06-15 13:07:29 -07:00
parent bb1d043fb2
commit 0856b398eb
1 changed files with 58 additions and 21 deletions
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79
src/main/java/us/camin/regions/geometry/BorderMesh.java
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@ -24,23 +24,31 @@ public class BorderMesh {
Map<Region, Polygon> m_polygons;
Map<Region, Set<Region>> m_neighbors;
// TODO: Probably need to cache the neighbors after doing all this
// intersection work! Should be generated during triangulate()
public Collection<Region> neighbors(Region region) {
Collection<Region> ret = new ArrayList<Region>();
if (m_neighbors.containsKey(region)) {
Collection<Region> allNeighbors = m_neighbors.get(region);
if (false /*isFrontier(region)*/) {
//log.trace("Region " + region.name() + " is a frontier");
for(Region neighbor : allNeighbors) {
if (!isFrontier(neighbor)) {
ret.add(neighbor);
} else {
//log.trace("Not linking " + region.name() + " to " + neighbor.name() + " as it is also a frontier");
for(Region neighbor : allNeighbors) {
int crossings = 0;
Vector2D start = new Vector2D(region.location().getBlockX(), region.location().getBlockZ());
Vector2D neighborEnd = new Vector2D(neighbor.location().getBlockX(), neighbor.location().getBlockZ());
for(Region distantNeighbor : m_regions) {
if (distantNeighbor.equals(neighbor)) {
continue;
}
Polygon poly = m_polygons.get(distantNeighbor);
for(Polygon.Segment edge : poly.segments()) {
// Check if the line from region->neighbor intersects with
// any polygon
if (doIntersect(start, neighborEnd, edge.start, edge.end)) {
crossings++;
}
}
}
} else {
//log.trace("Region " + region.name() + " is not a frontier");
for(Region neighbor : allNeighbors) {
ret.add(neighbor);
if (crossings == 1 || crossings == 0) {
ret.add(neighbor);
}
}
}
@ -58,6 +66,24 @@ public class BorderMesh {
public double y[];
public double z[];
public class Segment {
public Vector2D start;
public Vector2D end;
public Segment(Vector2D start, Vector2D end) {
this.start = start;
this.end = end;
}
}
public List<Segment> segments() {
List<Segment> ret = new ArrayList<Segment>();
for(int i = 0; i < x.length-1; i++) {
ret.add(new Segment(new Vector2D(x[i], z[i]), new Vector2D(x[i+1], z[i+1])));
}
ret.add(new Segment(new Vector2D(x[x.length-1], z[z.length-1]), new Vector2D(x[0], z[0])));
return ret;
}
public Polygon(List<Vector2D> points) {
x = new double[points.size()];
y = new double[points.size()];
@ -93,6 +119,27 @@ public class BorderMesh {
}
}
private int orientation(Vector2D p, Vector2D q, Vector2D r) {
int val = (int)((q.y - p.y) * (r.x - q.x) - (q.x - p.x) * (r.y - q.y));
if (val == 0) return 0; // colinear
return (val > 0) ? 1 : 2; // Clockwise or counter-clockwise
}
private boolean doIntersect(Vector2D p1, Vector2D q1, Vector2D p2, Vector2D q2) {
int o1 = orientation(p1, q1, p2);
int o2 = orientation(p1, q1, q2);
int o3 = orientation(p2, q2, p1);
int o4 = orientation(p2, q2, q1);
if (o1 != o2 && o3 != o4) {
return true;
}
// It probably isn't possible to generate a route that is colinear with a
// region border, so assume it isn't intersecting.
return false;
}
public Polygon polygonForRegion(Region r) {
return m_polygons.get(r);
}
@ -188,16 +235,6 @@ public class BorderMesh {
}
}*/
public boolean isFrontier(Region region) {
Polygon poly = polygonForRegion(region);
Location center = region.location();
if (poly.contains(center.getBlockX(), center.getBlockZ())) {
return false;
} else {
return true;
}
}
private boolean vecEquals(Vector2D a, Vector2D b) {
return a.x == b.x && a.y == b.y;
}