//Show points
private void ShowPoints(HashSet <MyVector2> points)
{
//Clear previous points
//Remove all old meshes
controller.ClearBlackMeshes();
foreach (MyVector2 p in points)
{
controller.GenerateCircleMesh(p, shouldResetAllMeshes: false);
}
}
//Flip edges until we get a delaunay triangulation
private IEnumerator FlipEdges(HalfEdgeData2 triangleData)
{
//The edges we want to flip
HashSet <HalfEdge2> edges = triangleData.edges;
//To avoid getting stuck in infinite loop
int safety = 0;
//Count how many edges we have flipped, which may be interesting to display
int flippedEdges = 0;
while (true)
{
safety += 1;
if (safety > 100000)
{
Debug.Log("Stuck in endless loop when flipping edges to get a Delaunay triangulation");
break;
}
bool hasFlippedEdge = false;
//Search through all edges to see if we can flip an edge
foreach (HalfEdge2 thisEdge in edges)
{
//Is this edge sharing an edge with another triangle, otherwise its a border, and then we cant flip the edge
if (thisEdge.oppositeEdge == null)
{
continue;
}
//The positions of the vertices belonging to the two triangles that we might flip
//a-c should be the edge that we might flip
MyVector2 a = thisEdge.v.position;
MyVector2 b = thisEdge.nextEdge.v.position;
MyVector2 c = thisEdge.nextEdge.nextEdge.v.position;
MyVector2 d = thisEdge.oppositeEdge.nextEdge.v.position;
//If we want to display the test circle
//controller.GenerateDelaunayCircleMeshes(a, b, c, d);
//yield return new WaitForSeconds(controller.pauseTime);
//Test if we should flip this edge
if (DelaunayMethods.ShouldFlipEdge(a, b, c, d))
{
flippedEdges += 1;
hasFlippedEdge = true;
HalfEdgeHelpMethods.FlipTriangleEdge(thisEdge);
controller.flipText.text = "Flipped edges: " + flippedEdges;
controller.GenerateTriangulationMesh(triangleData);
yield return(new WaitForSeconds(controller.pauseTime));
}
}
//We have searched through all edges and havent found an edge to flip, so we have a Delaunay triangulation!
if (!hasFlippedEdge)
{
Debug.Log("Found a delaunay triangulation in " + flippedEdges + " flips");
break;
}
}
//Remove the circle meshes so we see that we are finished
controller.ClearBlackMeshes();
yield return(null);
}
IEnumerator InsertPoints(HashSet <MyVector2> points, HalfEdgeData2 triangulationData, Triangle2 superTriangle)
{
//Visualize the first triangle
controller.GenerateTriangulationMesh(triangulationData);
yield return(new WaitForSeconds(controller.pauseTime));
//Step 4. Loop over each point we want to insert and do Steps 5-7
//These are for display purposes only
int missedPoints = 0;
int flippedEdges = 0;
foreach (MyVector2 p in points)
{
//Step 5. Insert the new point in the triangulation
//Find the existing triangle the point is in
HalfEdgeFace2 f = PointTriangulationIntersection.TriangulationWalk(p, null, triangulationData);
//We couldnt find a triangle maybe because the point is not in the triangulation?
if (f == null)
{
missedPoints += 1;
}
//Delete this triangle and form 3 new triangles by connecting p to each of the vertices in the old triangle
HalfEdgeHelpMethods.SplitTriangleFaceAtPoint(f, p, triangulationData);
//Visualize
//Display the point as a black circle
controller.GenerateCircleMesh(p, shouldResetAllMeshes: true);
yield return(new WaitForSeconds(controller.pauseTime));
controller.GenerateTriangulationMesh(triangulationData);
yield return(new WaitForSeconds(controller.pauseTime));
//Step 6. Initialize stack. Place all triangles which are adjacent to the edges opposite p on a LIFO stack
//The report says we should place triangles, but it's easier to place edges with our data structure
Stack <HalfEdge2> trianglesToInvestigate = new Stack <HalfEdge2>();
AddTrianglesOppositePToStack(p, trianglesToInvestigate, triangulationData);
//Step 7. Restore delaunay triangulation
//While the stack is not empty
int safety = 0;
while (trianglesToInvestigate.Count > 0)
{
safety += 1;
if (safety > 1000000)
{
Debug.Log("Stuck in infinite loop when restoring delaunay in incremental sloan algorithm");
break;
}
//Step 7.1. Remove a triangle from the stack
HalfEdge2 edgeToTest = trianglesToInvestigate.Pop();
//Step 7.2. Do we need to flip this edge?
//If p is outside or on the circumcircle for this triangle, we have a delaunay triangle and can return to next loop
MyVector2 a = edgeToTest.v.position;
MyVector2 b = edgeToTest.prevEdge.v.position;
MyVector2 c = edgeToTest.nextEdge.v.position;
//abc are here counter-clockwise
if (DelaunayMethods.ShouldFlipEdgeStable(a, b, c, p))
{
HalfEdgeHelpMethods.FlipTriangleEdge(edgeToTest);
//Step 7.3. Place any triangles which are now opposite p on the stack
AddTrianglesOppositePToStack(p, trianglesToInvestigate, triangulationData);
flippedEdges += 1;
//Visualize
controller.flipText.text = "Flipped edges: " + flippedEdges;
controller.GenerateTriangulationMesh(triangulationData);
yield return(new WaitForSeconds(controller.pauseTime));
}
}
}
controller.ClearBlackMeshes();
//Step 8. Delete the vertices belonging to the supertriangle
StartCoroutine(RemoveSuperTriangle(superTriangle, triangulationData));
yield return(null);
}
