/*-------------------------------------------------------------------*/
void PrintOut( tVertex v )
{
fprintf( stderr, "\nHead vertex %d = %p :\n", v->vnum, v );
PrintVertices();
PrintEdges();
PrintFaces();
}
main()
{
ReadVertices();
PrintVertices();
printf("%%Area of polygon = %g\n", 0.5 * AreaPoly2() );
Triangulate();
printf("showpage\n%%%%EOF\n");
}
// Enhance the polygon with trapezoids.
bool ConvertPointsToVertices(size_t numPts, const SkPoint *pts, Vertex *vta) {
DebugPrintf("ConvertPointsToVertices()\n");
// Clear everything.
DebugPrintf("Zeroing vertices\n");
sk_bzero(vta, numPts * sizeof(*vta));
// Initialize vertices.
DebugPrintf("Initializing vertices\n");
SetVertexPoints(numPts, pts, vta);
InitializeVertexTopology(numPts, vta);
PrintVertices(numPts, vta);
SkTDArray<VertexPtr> vtptr;
vtptr.setCount(numPts);
for (int i = numPts; i-- != 0;)
vtptr[i].vt = vta + i;
PrintVertexPtrs(vtptr.count(), vtptr.begin(), vta);
DebugPrintf("Sorting vertrap ptr array [%d] %p %p\n", vtptr.count(),
&vtptr[0], &vtptr[vtptr.count() - 1]
);
// SkTHeapSort(vtptr.begin(), vtptr.count());
BubbleSort(vtptr.begin(), vtptr.count());
DebugPrintf("Done sorting\n");
PrintVertexPtrs(vtptr.count(), vtptr.begin(), vta);
DebugPrintf("Traversing sorted vertrap ptrs\n");
ActiveTrapezoids incompleteTrapezoids;
for (VertexPtr *vtpp = vtptr.begin(); vtpp < vtptr.end(); ++vtpp) {
DebugPrintf("%d: sorted vertrap %d\n",
vtpp - vtptr.begin(), vtpp->vt - vta);
Vertex *vt = vtpp->vt;
Vertex *e0, *e1;
Trapezoid *t;
switch (vt->classify(&e0, &e1)) {
case Vertex::MONOTONE:
monotone:
DebugPrintf("MONOTONE %d %d\n", e0 - vta, e1 - vta);
// We should find one edge.
t = incompleteTrapezoids.getTrapezoidWithEdge(e0);
if (t == NULL) { // One of the edges is flat.
DebugPrintf("Monotone: cannot find a trapezoid with e0: "
"trying convex\n");
goto convex;
}
t->setBottom(vt); // This trapezoid is now complete.
incompleteTrapezoids.remove(t);
if (e0 == t->left()) // Replace the left edge.
incompleteTrapezoids.insertNewTrapezoid(vt, e1, t->right());
else // Replace the right edge.
incompleteTrapezoids.insertNewTrapezoid(vt, t->left(), e1);
break;
case Vertex::CONVEX: // Start of a new trapezoid.
convex:
// We don't expect to find any edges.
DebugPrintf("CONVEX %d %d\n", e0 - vta, e1 - vta);
if (incompleteTrapezoids.withinActiveTrapezoid(
vt->point(), &t)) {
// Complete trapezoid.
SkASSERT(t != NULL);
t->setBottom(vt);
incompleteTrapezoids.remove(t);
// Introduce two new trapezoids.
incompleteTrapezoids.insertNewTrapezoid(vt, t->left(), e0);
incompleteTrapezoids.insertNewTrapezoid(vt, e1, t->right());
} else {
// Insert a new trapezoid.
incompleteTrapezoids.insertNewTrapezoid(vt, e0, e1);
}
break;
case Vertex::CONCAVE: // End of a trapezoid.
DebugPrintf("CONCAVE %d %d\n", e0 - vta, e1 - vta);
// We should find two edges.
t = incompleteTrapezoids.getTrapezoidWithEdge(e0);
if (t == NULL) {
DebugPrintf("Concave: cannot find a trapezoid with e0: "
" trying monotone\n");
goto monotone;
}
SkASSERT(t != NULL);
if (e0 == t->left() && e1 == t->right()) {
DebugPrintf(
"Concave edges belong to the same trapezoid.\n");
// Edges belong to the same trapezoid.
// Complete trapezoid & transfer it from the active list.
t->setBottom(vt);
incompleteTrapezoids.remove(t);
} else { // Edges belong to different trapezoids
DebugPrintf(
"Concave edges belong to different trapezoids.\n");
// Complete left and right trapezoids.
Trapezoid *s = incompleteTrapezoids.getTrapezoidWithEdge(
e1);
if (s == NULL) {
DebugPrintf(
"Concave: cannot find a trapezoid with e1: "
" trying monotone\n");
goto monotone;
}
t->setBottom(vt);
s->setBottom(vt);
incompleteTrapezoids.remove(t);
incompleteTrapezoids.remove(s);
// Merge the two trapezoids into one below this vertex.
incompleteTrapezoids.insertNewTrapezoid(vt, t->left(),
s->right());
}
break;
}
}
RemoveDegenerateTrapezoids(numPts, vta);
DebugPrintf("Done making trapezoids\n");
PrintVertexPtrs(vtptr.count(), vtptr.begin(), vta);
size_t k = incompleteTrapezoids.count();
if (k > 0) {
FailureMessage("%d incomplete trapezoids\n", k);
return false;
}
return true;
}
