public bool BridgeAngle(Polygons areaGoingOnTop, long perimeterExpandDistance, out double bridgeAngle, Polygons bridgeAreas, string debugName = "")
{
SliceLayer layerToRestOn = this;
bridgeAngle = -1;
var boundaryBox = new Aabb(areaGoingOnTop);
boundaryBox.Expand(perimeterExpandDistance);
// To detect if we have a bridge, first calculate the intersection of the current layer with the previous layer.
// This gives us the islands that the layer rests on.
var islandsToRestOn = new Polygons();
foreach (LayerIsland islandToRestOn in layerToRestOn.Islands)
{
if (!boundaryBox.Hit(islandToRestOn.BoundingBox))
{
continue;
}
islandsToRestOn.AddRange(areaGoingOnTop.CreateIntersection(islandToRestOn.IslandOutline));
}
if (bridgeAreas != null)
{
bridgeAreas.AddRange(areaGoingOnTop.CreateDifference(layerToRestOn.AllOutlines));
}
if (outputDebugData)
{
WriteDebugData(areaGoingOnTop, layerToRestOn, islandsToRestOn);
}
if (islandsToRestOn.Count > 5 || islandsToRestOn.Count < 1)
{
return(false);
}
if (islandsToRestOn.Count == 1)
{
return(GetSingleIslandAngle(areaGoingOnTop, islandsToRestOn[0], out bridgeAngle, debugName));
}
// Find the 2 largest islands that we rest on.
double biggestArea = 0;
double nextBiggestArea = 0;
int indexOfBiggest = -1;
int indexOfNextBigest = -1;
for (int islandIndex = 0; islandIndex < islandsToRestOn.Count; islandIndex++)
{
// Skip internal holes
if (!islandsToRestOn[islandIndex].Orientation())
{
continue;
}
double area = Math.Abs(islandsToRestOn[islandIndex].Area());
if (area > biggestArea)
{
if (biggestArea > nextBiggestArea)
{
nextBiggestArea = biggestArea;
indexOfNextBigest = indexOfBiggest;
}
biggestArea = area;
indexOfBiggest = islandIndex;
}
else if (area > nextBiggestArea)
{
nextBiggestArea = area;
indexOfNextBigest = islandIndex;
}
}
if (indexOfBiggest < 0 || indexOfNextBigest < 0)
{
return(false);
}
IntPoint center1 = islandsToRestOn[indexOfBiggest].CenterOfMass();
IntPoint center2 = islandsToRestOn[indexOfNextBigest].CenterOfMass();
bridgeAngle = Math.Atan2(center2.Y - center1.Y, center2.X - center1.X) / Math.PI * 180;
Range0To360(ref bridgeAngle);
if (outputDebugData)
{
islandsToRestOn.SaveToGCode("{0} - angle {1:0.}.gcode".FormatWith(debugName, bridgeAngle));
}
return(true);
}
