public static void GenerateHexLinePaths(Polygons in_outline, ref Polygons result, int lineSpacing, int infillExtendIntoPerimeter_um, double rotationDegrees, int layerIndex)
{
int extraRotationAngle = 0;
if (in_outline.Count > 0)
{
Polygons outlines = in_outline.Offset(infillExtendIntoPerimeter_um);
if (outlines.Count > 0)
{
int perIncrementOffset = (int)(lineSpacing * Math.Sqrt(3) / 2 + .5);
PointMatrix matrix = new PointMatrix(-(rotationDegrees + extraRotationAngle)); // we are rotating the part so we rotate by the negative so the lines go the way we expect
outlines.applyMatrix(matrix);
AABB boundary = new AABB(outlines);
boundary.min.X = ((boundary.min.X / lineSpacing) - 1) * lineSpacing;
boundary.min.Y = ((boundary.min.Y / perIncrementOffset) - 1) * perIncrementOffset;
boundary.max.X += lineSpacing;
boundary.max.Y += perIncrementOffset;
Polygons unclipedPatern = new Polygons();
foreach (IntPoint startPoint in StartPositionIterator(boundary, lineSpacing, layerIndex))
{
Polygon attachedLine = new Polygon();
foreach (IntPoint center in IncrementPositionIterator(startPoint, boundary, lineSpacing, layerIndex))
{
// what we are adding are the little plusses that define the points
// | top
// |
// /\ center
// left/ \ right
//
IntPoint left = center + new IntPoint(-lineSpacing / 2, -perIncrementOffset / 3);
IntPoint right = center + new IntPoint(lineSpacing / 2, -perIncrementOffset / 3);
IntPoint top = center + new IntPoint(0, perIncrementOffset * 2 / 3);
switch (layerIndex % 3)
{
case 0: // left to right
attachedLine.Add(left); attachedLine.Add(center);
attachedLine.Add(center); attachedLine.Add(right);
unclipedPatern.Add(new Polygon()
{
top, center
});
break;
case 1: // left to top
attachedLine.Add(left); attachedLine.Add(center);
attachedLine.Add(center); attachedLine.Add(top);
unclipedPatern.Add(new Polygon()
{
center, right
});
break;
case 2: // top to right
attachedLine.Add(top); attachedLine.Add(center);
attachedLine.Add(center); attachedLine.Add(right);
unclipedPatern.Add(new Polygon()
{
left, center
});
break;
}
}
if (attachedLine.Count > 0)
{
unclipedPatern.Add(attachedLine);
}
}
PolyTree ret = new PolyTree();
Clipper clipper = new Clipper();
clipper.AddPaths(unclipedPatern, PolyType.ptSubject, false);
clipper.AddPaths(outlines, PolyType.ptClip, true);
clipper.Execute(ClipType.ctIntersection, ret, PolyFillType.pftPositive, PolyFillType.pftEvenOdd);
Polygons newSegments = Clipper.OpenPathsFromPolyTree(ret);
PointMatrix inversematrix = new PointMatrix((rotationDegrees + extraRotationAngle));
newSegments.applyMatrix(inversematrix);
result.AddRange(newSegments);
}
}
}
private static IEnumerable <IntPoint> StartPositionIterator(AABB boundary, int lineSpacing, int layerIndex)
{
int perIncrementOffset = (int)(lineSpacing * Math.Sqrt(3) / 2 + .5);
int yLineCount = (int)((boundary.max.Y - boundary.min.Y + perIncrementOffset) / perIncrementOffset) + 1;
switch (layerIndex % 3)
{
case 0: // left to right
for (int yIndex = 0; yIndex < yLineCount; yIndex++)
{
long yPosition = boundary.min.Y + yIndex * perIncrementOffset;
bool removeXOffset = ((yPosition / perIncrementOffset) % 2) == 0;
long xOffsetForY = lineSpacing / 2;
if (removeXOffset) // if we are at every other y
{
xOffsetForY = 0;
}
long firstX = boundary.min.X + xOffsetForY;
yield return(new IntPoint(firstX, yPosition));
}
break;
case 1: // left to top
{
IntPoint nextPoint = new IntPoint();
for (int yIndex = yLineCount; yIndex >= 0; yIndex--)
{
long yPosition = boundary.min.Y + yIndex * perIncrementOffset;
bool createLineSegment = ((yPosition / perIncrementOffset) % 2) == 0;
if (createLineSegment)
{
nextPoint = new IntPoint(boundary.min.X, yPosition);
yield return(nextPoint);
}
}
IntPoint positionAdd = new IntPoint(lineSpacing, 0);
nextPoint += positionAdd;
while (nextPoint.X > boundary.min.X &&
nextPoint.X < boundary.max.X)
{
yield return(nextPoint);
nextPoint += positionAdd;
}
}
break;
case 2: // top to right
{
IntPoint nextPoint = new IntPoint();
for (int yIndex = 0; yIndex < yLineCount; yIndex++)
{
long yPosition = boundary.min.Y + yIndex * perIncrementOffset;
bool createLineSegment = ((yPosition / perIncrementOffset) % 2) == 0;
if (createLineSegment)
{
nextPoint = new IntPoint(boundary.min.X, yPosition);
yield return(nextPoint);
}
}
IntPoint positionAdd = new IntPoint(lineSpacing, 0);
nextPoint += positionAdd;
while (nextPoint.X > boundary.min.X &&
nextPoint.X < boundary.max.X)
{
yield return(nextPoint);
nextPoint += positionAdd;
}
}
break;
}
}
private static IEnumerable <IntPoint> IncrementPositionIterator(IntPoint startPoint, AABB boundary, int lineSpacing, int layerIndex)
{
IntPoint positionAdd = new IntPoint(lineSpacing, 0);
int perIncrementOffset = (int)(lineSpacing * Math.Sqrt(3) / 2 + .5);
switch (layerIndex % 3)
{
case 0: // left to right
positionAdd = new IntPoint(lineSpacing, 0);
break;
case 1: // left to top
positionAdd = new IntPoint(lineSpacing / 2, perIncrementOffset);
break;
case 2: // top to right
positionAdd = new IntPoint(lineSpacing / 2, -perIncrementOffset);
break;
}
IntPoint nextPoint = startPoint;
do
{
yield return(nextPoint);
nextPoint += positionAdd;
} while (nextPoint.X > boundary.min.X &&
nextPoint.X < boundary.max.X &&
nextPoint.Y > boundary.min.Y &&
nextPoint.Y < boundary.max.Y);
}