private void TestFlip(List <Vector3> points, Triangles triangles, WorkBuffer <Int2> stack, int a, int b, int x)
{
var y = triangles.Opposite(a, b);
//Test boundary edge
if (y < 0)
{
return;
}
//Swap edge if order flipped
if (b < a)
{
var tmp = a;
a = b;
b = tmp;
tmp = x;
x = y;
y = tmp;
}
//Test if edge is constrained
if (triangles.IsConstraint(a, b))
{
return;
}
//Test if edge is delaunay
if (Robust.InSphere(points[a], points[b], points[x], points[y]) < 0f)
{
var v = new Int2(a, b);
stack.Push(ref v);
}
}
public void InSphere()
{
Assert.IsTrue(Robust.InSphere(
new Vector2(0f, -1f),
new Vector2(1f, 0f),
new Vector2(0f, 1f),
new Vector2(-0.5f, 0f)) > 0f);
Assert.IsTrue(Robust.InSphere(
new Vector2(0f, -1f),
new Vector2(1f, 0f),
new Vector2(0f, 1f),
new Vector2(-1f, 0f)) == 0f);
Assert.IsTrue(Robust.InSphere(
new Vector2(0f, -1f),
new Vector2(1f, 0f),
new Vector2(0f, 1f),
new Vector2(-1.5f, 0f)) < 0f);
var x = 1e-4f;
for (var i = 0; i < 8; ++i)
{
Assert.IsTrue(Robust.InSphere(
new Vector2(0f, x),
new Vector2(-x, -x),
new Vector2(x, -x),
new Vector2(0f, 0f)) > 0f, "sphere test:" + x);
Assert.IsTrue(Robust.InSphere(
new Vector2(0f, x),
new Vector2(-x, -x),
new Vector2(x, -x),
new Vector2(0f, 2f * x)) < 0f, "sphere test:" + x);
Assert.IsTrue(Robust.InSphere(
new Vector2(0f, x),
new Vector2(-x, -x),
new Vector2(x, -x),
new Vector2(0f, x)) == 0f, "sphere test:" + x);
x *= 10f;
}
}
//Assume edges are sorted lexicographically
public void RefineTriangles(Triangles triangles)
{
var stack = WorkBufferPool.Get <Int2>();
var points = triangles.Vertices;
var numPoints = points.Count;
var stars = triangles.Stars;
for (var a = 0; a < numPoints; ++a)
{
var star = stars[a];
var starData = star.Data;
var sl = star.UsedSize;
for (var j = 0; j < sl; ++j)
{
var s = starData[j];
var b = s.y;
//If order is not consistent, then skip edge
if (b < a)
{
continue;
}
//Check if edge is constrained
if (triangles.IsConstraint(a, b))
{
continue;
}
//Find opposite edge
var x = s.x;
var y = -1;
for (var k = 0; k < sl; ++k)
{
if (starData[k].x == b)
{
y = starData[k].y;
break;
}
}
//If this is a boundary edge, don't flip it
if (y < 0)
{
continue;
}
//If edge is in circle, flip it
if (Robust.InSphere(points[a], points[b], points[x], points[y]) < 0f)
{
var v = new Int2(a, b);
stack.Push(ref v);
}
}
}
while (stack.UsedSize > 0)
{
var v = stack.Pop();
var a = v.x;
var b = v.y;
//Find opposite pairs
var x = -1;
var y = -1;
var star = stars[a];
var starData = star.Data;
var sl = star.UsedSize;
for (var i = 0; i < sl; ++i)
{
var s = starData[i].x;
var t = starData[i].y;
if (s == b)
{
y = t;
}
else if (t == b)
{
x = s;
}
}
//If x/y are both valid then skip edge
if (x < 0 || y < 0)
{
continue;
}
//If edge is now delaunay, then don't flip it
if (Robust.InSphere(points[a], points[b], points[x], points[y]) >= 0f)
{
continue;
}
//Flip the edge
triangles.Flip(a, b);
//Test flipping neighboring edges
TestFlip(points, triangles, stack, x, a, y);
TestFlip(points, triangles, stack, a, y, x);
TestFlip(points, triangles, stack, y, b, x);
TestFlip(points, triangles, stack, b, x, y);
}
WorkBufferPool.Release(ref stack);
}
