/// <summary>
/// Initialise a new Extrusion object representing an
/// extrusion of the specified profile along the specified path
/// </summary>
/// <param name="profile">The profile surface to extrude</param>
/// <param name="path">The extrusion vector</param>
public Extrusion(PlanarRegion profile, Vector path)
{
_Profile = profile;
_Path = path;
}
/// <summary>
/// Split this region into two (or more) sub-regions along a straight line
/// </summary>
/// <param name="splitPt">A point on the splitting line</param>
/// <param name="splitDir">The direction of the line</param>
/// <param name="splitWidth">Optional. The width of the split.</param>
/// <returns>The resultant list of regions. If the line does not bisect
/// this region and the region could not be split, this collection will contain
/// only the original region.</returns>
public IList <PlanarRegion> SplitByLineXY2(Vector splitPt, Vector splitDir, double splitWidth = 0)
{
var result = new List <PlanarRegion>();
// Offset splitting line by half splitWidth in each direction:
Vector offsetDir = splitDir.PerpendicularXY().Unitize();
Vector offset = offsetDir * splitWidth / 2;
Vector leftPt = splitPt + offset;
Vector rightPt = splitPt - offset;
// Find intersection points on perimeter:
var perimeterInts = new List <CurveLineIntersection>();
// Left side:
IList <CurveLineIntersection> leftInts = Intersect.CurveLineXYIntersections(Perimeter, leftPt, splitDir);
perimeterInts.AddRange(leftInts);
IList <CurveLineIntersection> rightInts;
// Shortcut: If the split has no width, left and right intersections will be the same
if (splitWidth == 0)
{
rightInts = leftInts;
}
else
{
rightInts = Intersect.CurveLineXYIntersections(Perimeter, rightPt, splitDir);
perimeterInts.AddRange(rightInts);
}
// If no intersections on the perimeter, the region does not need to be split:
if (leftInts.Count <= 1 && rightInts.Count <= 1)
{
result.Add(this);
return(result);
}
// Voids which do not intersect but will need to be placed:
CurveCollection freeVoids = new CurveCollection();
// Find intersection points on voids:
foreach (var voidCrv in Voids)
{
// Left side:
var leftVoidInts = Intersect.CurveLineXYIntersections(voidCrv, leftPt, splitDir);
foreach (var vI in leftVoidInts)
{
leftInts.Add(vI);
}
IList <CurveLineIntersection> rightVoidInts;
// Shortcut: If the split has no width, left and right intersections will be the same
if (splitWidth == 0)
{
rightVoidInts = leftVoidInts;
}
else
{
rightVoidInts = Intersect.CurveLineXYIntersections(voidCrv, rightPt, splitDir);
}
foreach (var vI in rightVoidInts)
{
rightInts.Add(vI);
}
if (leftVoidInts.Count <= 1 && rightVoidInts.Count <= 1)
{
// Void is wholly to one side or the other...
freeVoids.Add(voidCrv);
}
}
// Tag left and right intersections
foreach (var lI in leftInts)
{
lI.Side = HandSide.Left;
}
foreach (var rI in rightInts)
{
rI.Side = HandSide.Right;
}
// Determine direction of travel along cutting lines:
int rightDir = RightCutterDirectionOfTravel(perimeterInts);
// 'Fake' intersection to represent perimeter start:
CurveLineIntersection startInt = new CurveLineIntersection(Perimeter, 0, double.NaN);
// Loop through intersections and build up new sub-regions by traversing connected
// intersections along the perimeter, cutting lines and void curves
CurveLineIntersection currentInt = startInt;
CurveLineIntersection nextStartInt = null;
PolyCurve newPerimeter = null;
PlanarRegion newRegion = null;
// The cutter to travel along (Undefined is perimeter or void cuve):
HandSide travelSide = HandSide.Undefined;
int segmentCount = perimeterInts.Count + 1; //TODO: Include void intersections
for (int i = 0; i < segmentCount; i++) // Loop through intersections
{
CurveLineIntersection nextInt;
// Travel to next intersection, along the cutters or perimeter
if (travelSide == HandSide.Left)
{
// Travel along left cutter
if (rightDir == 1)
{
nextInt = leftInts.ItemWithPrevious(cLI => cLI.LineParameter, currentInt.LineParameter);
}
else
{
nextInt = leftInts.ItemWithNext(cLI => cLI.LineParameter, currentInt.LineParameter);
}
}
else if (travelSide == HandSide.Right)
{
// Travel along right cutter
if (rightDir == 1)
{
nextInt = rightInts.ItemWithNext(cLI => cLI.LineParameter, currentInt.LineParameter);
}
else
{
nextInt = rightInts.ItemWithPrevious(cLI => cLI.LineParameter, currentInt.LineParameter);
}
}
else
{
// Travel to next intersection on perimeter
nextInt = perimeterInts.ItemWithNext(cLI => cLI.CurveParameter, currentInt.CurveParameter);
// 'Fake' intersection to represent perimeter end:
if (nextInt == null)
{
nextInt = new CurveLineIntersection(Perimeter, 1, double.NaN);
}
if (nextStartInt == null)
{
nextStartInt = nextInt;
}
}
if (nextInt != null && currentInt.Curve == nextInt.Curve && // Check both ints on same curve
(travelSide == HandSide.Undefined || currentInt.Curve != Perimeter))
{
Curve curve = nextInt.Curve;
Interval subDomain = new Interval(currentInt.CurveParameter, nextInt.CurveParameter);
Vector crvPt = curve.PointAt(subDomain.Mid);
HandSide side = SideOfSplit(crvPt, leftPt, rightPt, offsetDir);
if (side != HandSide.Undefined)
{
// TODO: Adjust void curve direction
// Add perimeter to outputs
Curve subCrv = curve.Extract(subDomain);
if (newPerimeter == null)
{
newPerimeter = new PolyCurve(subCrv.Explode());
newRegion = new PlanarRegion(newPerimeter);
result.Add(newRegion);
}
else
{
newPerimeter.Add(subCrv, true, true);
}
}
else
{
//Traversing the gap, need a new start Point
startInt = nextInt;
}
}
// Next side to travel:
if (travelSide != HandSide.Undefined &&
(nextInt == null || nextInt.Curve == Perimeter))
{
travelSide = HandSide.Undefined;
}
else
{
travelSide = nextInt.Side;
}
if (nextInt == null || nextInt == startInt || nextInt.CurveParameter >= 1)
{
// Reset to start next segment
nextInt = nextStartInt;
startInt = nextStartInt;
nextStartInt = null;
if (newPerimeter != null)
{
newPerimeter.Close();
}
newPerimeter = null;
newRegion = null;
travelSide = HandSide.Undefined;
}
currentInt = nextInt;
}
if (newPerimeter != null)
{
newPerimeter.Close();
}
//TODO: Assign un-intersected voids
return(result);
}
/// <summary>
/// Initialise a new Extrusion object representing an
/// extrusion of the specified profile along the specified path
/// </summary>
/// <param name="profile">The profile perimeter curve. Must be planar.</param>
/// <param name="path">The extrusion vector</param>
public Extrusion(Curve profile, Vector path)
{
_Profile = new PlanarRegion(profile);
_Path = path;
}
