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Improve Delaunay triangulation implementation #1

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139 changes: 66 additions & 73 deletions src/nl/tue/geometrycore/algorithms/delaunay/DelaunayTriangulation.java
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Original file line number Diff line number Diff line change
Expand Up @@ -79,7 +79,7 @@ private TVertex compute(int low, int high) {
System.err.println("Should not occur");
return null;
case 1: {
// one vertex
// one vertex
// System.err.println("CALL " + low + "-" + (high - 1) + " :: " + _vertices.get(low) + "-" + _vertices.get(high - 1));
TVertex u = _vertices.get(low);
// System.err.println("RET " + u + " << " + low + "-" + (high - 1));
Expand All @@ -104,7 +104,10 @@ private TVertex compute(int low, int high) {
TVertex w = _vertices.get(low + 2);
addEdge(u, v);
addEdge(v, w);
addEdge(w, u);
// detects collinear by sine value
if (Vector.crossProduct(Vector.subtract(u, v), Vector.subtract(v, w)) != 0) {
addEdge(w, u);
}
TVertex min = u.getY() <= v.getY() && u.getY() <= w.getY()
? u : (v.getY() <= w.getY() ? v : w);
// System.err.println("RET " + min + " << " + low + "-" + (high - 1));
Expand Down Expand Up @@ -164,14 +167,24 @@ private TVertex compute(int low, int high) {

if (u_cand != null) {
if (addEdge(u_cand, v)) {
System.err.println("DUPLICATE EDGE -- aborting" + " << " + low + "-" + (high - 1));
return null;
// detects collinear by sine value
if (Vector.crossProduct(Vector.subtract(u, u_cand), Vector.subtract(v, u_cand)) == 0) {
_input.removeEdge(u.getEdgeTo(v));
} else {
System.err.println("DUPLICATE EDGE -- aborting" + " << " + low + "-" + (high - 1));
return null;
}
}
u = u_cand;
} else { // v_cand != null
} else { // v_cand != null
if (addEdge(u, v_cand)) {
System.err.println("DUPLICATE EDGE -- aborting" + " << " + low + "-" + (high - 1));
return null;
// detects collinear by sine value
if (Vector.crossProduct(Vector.subtract(u, v_cand), Vector.subtract(v, v_cand)) == 0) {
_input.removeEdge(u.getEdgeTo(v));
} else {
System.err.println("DUPLICATE EDGE -- aborting" + " << " + low + "-" + (high - 1));
return null;
}
}
v = v_cand;
}
Expand Down Expand Up @@ -245,10 +258,9 @@ private TVertex shiftHull(TVertex vertex, TVertex other, int mid, Side side) {
private TVertex candidate(TVertex vertex, TVertex other, int mid, Side side) {

Vector dir = Vector.subtract(other, vertex);
dir.normalize();

// System.err.println(" candidate? "+vertex+" "+other);

TVertex first = findFirst(vertex, dir, mid, side);
// System.err.println(" first "+first);
if (first == null) {
Expand All @@ -271,119 +283,100 @@ private TVertex candidate(TVertex vertex, TVertex other, int mid, Side side) {
private TVertex findFirst(TVertex vertex, Vector dir, int mid, Side side) {

TVertex min = null;
double opt = Double.POSITIVE_INFINITY;
double opt = Double.NEGATIVE_INFINITY;
for (TEdge e : vertex.getEdges()) {
TVertex nbr = e.getOtherVertex(vertex);
if (side == Side.LEFT && _graph_to_sorted[nbr.getGraphIndex()] >= mid) {
continue;
} else if (side == Side.RIGHT && _graph_to_sorted[nbr.getGraphIndex()] < mid) {
continue;
}
Vector edir = Vector.subtract(nbr, vertex);
edir.normalize();
double a = side == Side.LEFT
? dir.computeCounterClockwiseAngleTo(edir, false, false)
: dir.computeClockwiseAngleTo(edir, false, false);
// if (a > Math.PI * 2 - DoubleUtil.EPS) {
// a = 0;
// }
if (a < opt) {
Vector e_dir = Vector.subtract(nbr, vertex);
var cross = Vector.crossProduct(dir, e_dir);
var dot = Vector.dotProduct(dir, e_dir);
if (cross == 0) {
if (dot < 0) {
continue; // theta = pi
}
} else if ((side == Side.LEFT) ^ (cross > 0)) {
continue; // theta > pi
}
var cos_sim = dot / (dir.length() * e_dir.length());
if (cos_sim > opt) {
min = nbr;
opt = a;
opt = cos_sim;
}
}

if (min == null) {
return null;
}

if (opt >= Math.PI) {
return null;
}

return min;
}

private TVertex findSecond(TVertex vertex, Vector dir, int mid, Side side) {

TVertex min = null;
double opt = Double.POSITIVE_INFINITY;
double opt = Double.NEGATIVE_INFINITY;
TVertex sec = null;
double sec_opt = Double.POSITIVE_INFINITY;
double sec_opt = Double.NEGATIVE_INFINITY;
for (TEdge e : vertex.getEdges()) {

TVertex nbr = e.getOtherVertex(vertex);
if (side == Side.LEFT && _graph_to_sorted[nbr.getGraphIndex()] >= mid) {
continue;
} else if (side == Side.RIGHT && _graph_to_sorted[nbr.getGraphIndex()] < mid) {
continue;
}
Vector edir = Vector.subtract(nbr, vertex);
edir.normalize();
double a = side == Side.LEFT
? dir.computeCounterClockwiseAngleTo(edir, false, false)
: dir.computeClockwiseAngleTo(edir, false, false);

// System.err.println(" "+nbr+" :: "+a);
// if (a > Math.PI * 2 - DoubleUtil.EPS) {
// a = 0;
// }
if (a < opt) {
Vector e_dir = Vector.subtract(nbr, vertex);
var cross = Vector.crossProduct(dir, e_dir);
var dot = Vector.dotProduct(dir, e_dir);
if (cross == 0) {
if (dot < 0) {
continue; // theta = pi
}
} else if ((side == Side.LEFT) ^ (cross > 0)) {
continue; // theta > pi
}
var cos_sim = dot / (dir.length() * e_dir.length());
if (cos_sim > opt) {
sec = min;
sec_opt = opt;
min = nbr;
opt = a;
} else if (a < sec_opt) {
opt = cos_sim;
} else if (cos_sim > sec_opt) {
sec = nbr;
sec_opt = a;
sec_opt = cos_sim;
}
}

if (sec == null) {
return null;
}

if (sec_opt >= Math.PI) {
return null;
}

return sec;
}

private TVertex findLast(TVertex vertex, Vector dir, int mid, Side side) {

TVertex min = null;
double opt = Double.POSITIVE_INFINITY;
double opt = Double.NEGATIVE_INFINITY;
for (TEdge e : vertex.getEdges()) {
TVertex nbr = e.getOtherVertex(vertex);
if (side == Side.LEFT && _graph_to_sorted[nbr.getGraphIndex()] >= mid) {
continue;
} else if (side == Side.RIGHT && _graph_to_sorted[nbr.getGraphIndex()] < mid) {
continue;
}
Vector edir = Vector.subtract(nbr, vertex);
edir.normalize();
// SWAPPED WRT find first/second
double a = side == Side.RIGHT
? dir.computeCounterClockwiseAngleTo(edir, false, false)
: dir.computeClockwiseAngleTo(edir, false, false);
// if (a > Math.PI * 2 - DoubleUtil.EPS) {
// a = 0;
// }
if (a < opt) {
Vector e_dir = Vector.subtract(nbr, vertex);
var cross = Vector.crossProduct(dir, e_dir);
var dot = Vector.dotProduct(dir, e_dir);
if (cross == 0) {
if (dot < 0) {
continue; // theta = pi
}
} else if ((side == Side.LEFT) ^ (cross < 0)) { // SWAPPED WRT find first/second
continue; // theta >= pi
}
var cos_sim = dot / (dir.length() * e_dir.length());
if (cos_sim > opt) {
min = nbr;
opt = a;
opt = cos_sim;
}
}

if (min == null) {
return null;
}

if (opt >= Math.PI) {
return null;
}

return min;
}
}