public Path2D(List<PolyLine3d> pls3d)
{
try
{
points = new List<Point2D>();
segments = new List<Segment2D>();
polys = new List<Polyline2D>();
minx = miny = Double.MaxValue;
maxx = maxy = Double.MinValue;
// create dummy points to help with sorting
GetCreatePoint(0, 0);
//GetCreatePoint(1000000, 1000000);
foreach (PolyLine3d p3d in pls3d)
{
Point2D pt1 = GetCreatePoint(p3d.m_points[0].x, p3d.m_points[0].y);
Point2D pt2 = GetCreatePoint(p3d.m_points[1].x, p3d.m_points[1].y);
if (Object.ReferenceEquals(pt1, pt2)) // invalid segment
continue;
Segment2D seg = new Segment2D(pt1, pt2, p3d.m_derived.m_normal.x, p3d.m_derived.m_normal.y);
segments.Add(seg);
}
FindIntersections();
RemoveRedundant();
ConstructPolyLines();
}
catch (Exception ex)
{
DebugLogger.Instance().LogError(ex);
}
}
public double a, b; // for y = a * x + b
public SegPoint(Segment2D seg, int segix, bool isleft)
{
isLeft = isleft;
if (isleft)
{
pt = seg.p1.CompareTo(seg.p2) < 0 ? seg.p1 : seg.p2;
if (seg.p1.x == seg.p2.x)
{
a = 0;
b = pt.y;
}
else
{
a = (seg.p2.y - seg.p1.y) / (seg.p2.x - seg.p1.x);
b = seg.p2.y - a * seg.p2.x;
}
}
else
{
pt = seg.p1.CompareTo(seg.p2) < 0 ? seg.p2 : seg.p1;
}
this.seg = seg;
this.segix = segix;
}
public void Add(Segment2D seg)
{
// horizontal
if (Math.Abs(seg.p1.x - seg.p2.x) > Path2D.Epsilon)
{
int from = (int)((seg.pmin.x - minx - thgap) / hgap);
if (from < 0)
from = 0;
int to = (int)((seg.pmax.x - minx + thgap) / hgap);
for (int i = from; i <= to; i++)
hbins[i].Add(seg);
}
// vertical
if (Math.Abs(seg.p1.y - seg.p2.y) > Path2D.Epsilon)
{
int from = (int)((seg.pmin.y - miny - tvgap) / vgap);
if (from < 0)
from = 0;
int to = (int)((seg.pmax.y - miny + tvgap) / vgap);
for (int i = from; i <= to; i++)
vbins[i].Add(seg);
}
}
// find intersection between 2 segments. if they do intersect return new segments after
// splitting originals on the intersection point.
public List<Segment2D> Intersect(Segment2D seg, Path2D path)
{
// quickly eliminate non adjacent lines
if ((seg.pmax.y <= pmin.y) || (seg.pmin.y >= pmax.y) || (seg.pmax.x <= pmin.x) || (seg.pmin.x >= pmax.x))
return null;
// special case 1: sigments have same endpoints, nothing to do
if ((Object.ReferenceEquals(p1, seg.p1) && Object.ReferenceEquals(p2, seg.p2)) ||
(Object.ReferenceEquals(p2, seg.p1) && Object.ReferenceEquals(p1, seg.p2)))
return null;
double x21 = p2.x - p1.x;
double x43 = seg.p2.x - seg.p1.x;
double y21 = p2.y - p1.y;
double y43 = seg.p2.y - seg.p1.y;
double c = x21 * y43 - y21 * x43;
List<Segment2D> segments;
// if lines are parrallel, nothing to do
if (Math.Abs(c) <= Path2D.DEpsilon)
return null;
// lines are not parallel. if both lines share any edge, nothing to do
if (Object.ReferenceEquals(p1, seg.p1) || Object.ReferenceEquals(p2, seg.p2) ||
Object.ReferenceEquals(p2, seg.p1) || Object.ReferenceEquals(p1, seg.p2))
return null;
double x31 = seg.p1.x - p1.x;
double y31 = seg.p1.y - p1.y;
double u = (y43 * x31 - x43 * y31) / c;
double v = (y21 * x31 - x21 * y31) / c;
// if u or v are outside the 0-1 range, no intersection
if ((u < -Path2D.Epsilon) || (u > 1 + Path2D.Epsilon) || (v < -Path2D.Epsilon) || (v > 1 + Path2D.Epsilon))
return null;
// get intersection point
Point2D ip = path.GetCreatePoint(p1.x + u * x21, p1.y + u * y21);
segments = new List<Segment2D>();
// if ip is not on edge of lines, split them
if (!Object.ReferenceEquals(p1, ip) && !Object.ReferenceEquals(p2, ip))
segments.AddRange(SplitAt(ip));
else
segments.Add(this);
if (!Object.ReferenceEquals(seg.p1, ip) && !Object.ReferenceEquals(seg.p2, ip))
segments.AddRange(seg.SplitAt(ip));
else
segments.Add(seg);
return segments;
}
// this function finds intersection of seg with y line
// if no intersection or intersecton too close to x, do nothing
// find position of intersection, if it is to the right of x, update rightCount with segment direction
// otherwise update leftCount with segment direction
public void UpdateYcrossing(double y, double x, Segment2D seg, ref int leftCount, ref int rightCount)
{
int dir = 0;
if ((y >= seg.p1.y) && (y < seg.p2.y))
dir = -1;
else if ((y <= seg.p1.y) && (y > seg.p2.y))
dir = 1;
if (dir != 0)
{
double u = (y - seg.p1.y) / (seg.p2.y - seg.p1.y);
double xpos = seg.p1.x + u * (seg.p2.x - seg.p1.x);
if (Math.Abs(xpos - x) > Path2D.Epsilon)
{
if (xpos > x)
rightCount += dir;
else
leftCount -= dir;
}
}
}
// same as UpdateYcrossing but in vertical direction
public void UpdateXcrossing(double x, double y, Segment2D seg, ref int botCount, ref int topCount)
{
int dir = 0;
if ((x >= seg.p1.x) && (x < seg.p2.x))
dir = 1;
else if ((x <= seg.p1.x) && (x > seg.p2.x))
dir = -1;
if (dir != 0)
{
double u = (x - seg.p1.x) / (seg.p2.x - seg.p1.x);
double ypos = seg.p1.y + u * (seg.p2.y - seg.p1.y);
if (Math.Abs(ypos - y) > Path2D.Epsilon)
{
if (ypos > y)
topCount += dir;
else
botCount -= dir;
}
}
}
// segments represent an edge where the right side is inside the object and the left side is
// outside. when objects intersect some segments fall totaly inside the object. (left and right
// side is in the object). These segments are now redundant so we remove them.
public void RemoveRedundant()
{
int i, j, n_nonhoriz;
List <Segment2D> lineSegs;
try
{
// collect all horizontal segments and push them to the end, they will be processed in the vertical sweep
n_nonhoriz = segments.Count;
for (i = 0; i < n_nonhoriz; i++)
{
while ((i < n_nonhoriz) && (Math.Abs(segments[i].p1.y - segments[i].p2.y) <= Path2D.Epsilon))
{
Segment2D seg = segments[i];
segments.RemoveAt(i);
segments.Add(seg);
n_nonhoriz--;
}
}
SegmentBin sbin = new SegmentBin(minx, miny, maxx, maxy, 100);
sbin.Add(segments);
// horizontal sweep
for (i = 0; i < n_nonhoriz; i++)
{
Segment2D seg = segments[i];
double y = seg.p1.y + 0.61263546 * (seg.p2.y - seg.p1.y); // arbitrary point between y1 and y2.
double u = (y - seg.p1.y) / (seg.p2.y - seg.p1.y);
double xpos = seg.p1.x + u * (seg.p2.x - seg.p1.x);
int rightCount = 0;
int leftCount = 0;
/*for (j = 0; j < n_nonhoriz; j++)
* {
* if (j == i)
* continue;
* UpdateYcrossing(y, xpos, segments[j], ref leftCount, ref rightCount);
* }*/
lineSegs = sbin.GetVbin(y);
foreach (Segment2D seg1 in lineSegs)
{
if (!Object.ReferenceEquals(seg, seg1))
{
UpdateYcrossing(y, xpos, seg1, ref leftCount, ref rightCount);
}
}
// mark valid only the segments that one side count is zero and the other non zero
if (((leftCount == 0) && (rightCount != 0)) || ((leftCount != 0) && (rightCount == 0)))
{
seg.isValid = true;
}
}
// vertical sweep
for (i = n_nonhoriz; i < segments.Count; i++)
{
Segment2D seg = segments[i];
double x = seg.p1.x + 0.61263546f * (seg.p2.x - seg.p1.x); // arbitrary point between y1 and y2.
double u = (x - seg.p1.x) / (seg.p2.x - seg.p1.x);
double ypos = seg.p1.y + u * (seg.p2.y - seg.p1.y);
int topCount = 0;
int botCount = 0;
/*for (j = 0; j < segments.Count; j++)
* {
* if ((j == i) || (Math.Abs(segments[j].p1.x - segments[j].p2.x) <= Path2D.Epsilon)) // skip vertical lines
* continue;
* UpdateXcrossing(x, ypos, segments[j], ref botCount, ref topCount);
* }*/
lineSegs = sbin.GetHbin(x);
foreach (Segment2D seg1 in lineSegs)
{
if (!Object.ReferenceEquals(seg, seg1))
{
UpdateXcrossing(x, ypos, seg1, ref botCount, ref topCount);
}
}
// mark valid only the segments that one side count is zero and the other non zero
if (((botCount == 0) && (topCount != 0)) || ((botCount != 0) && (topCount == 0)))
{
seg.isValid = true;
}
}
}
catch (Exception ex)
{
DebugLogger.Instance().LogError(ex);
}
}
// find intersection between 2 segments. if they do intersect return new segments after
// splitting originals on the intersection point.
public List <Segment2D> Intersect(Segment2D seg, Path2D path)
{
// quickly eliminate non adjacent lines
if ((seg.pmax.y <= pmin.y) || (seg.pmin.y >= pmax.y) || (seg.pmax.x <= pmin.x) || (seg.pmin.x >= pmax.x))
{
return(null);
}
// special case 1: sigments have same endpoints, nothing to do
if ((Object.ReferenceEquals(p1, seg.p1) && Object.ReferenceEquals(p2, seg.p2)) ||
(Object.ReferenceEquals(p2, seg.p1) && Object.ReferenceEquals(p1, seg.p2)))
{
return(null);
}
double x21 = p2.x - p1.x;
double x43 = seg.p2.x - seg.p1.x;
double y21 = p2.y - p1.y;
double y43 = seg.p2.y - seg.p1.y;
double c = x21 * y43 - y21 * x43;
List <Segment2D> segments;
// if lines are parrallel, nothing to do
if (Math.Abs(c) <= Path2D.DEpsilon)
{
return(null);
}
// lines are not parallel. if both lines share any edge, nothing to do
if (Object.ReferenceEquals(p1, seg.p1) || Object.ReferenceEquals(p2, seg.p2) ||
Object.ReferenceEquals(p2, seg.p1) || Object.ReferenceEquals(p1, seg.p2))
{
return(null);
}
double x31 = seg.p1.x - p1.x;
double y31 = seg.p1.y - p1.y;
double u = (y43 * x31 - x43 * y31) / c;
double v = (y21 * x31 - x21 * y31) / c;
// if u or v are outside the 0-1 range, no intersection
if ((u < -Path2D.Epsilon) || (u > 1 + Path2D.Epsilon) || (v < -Path2D.Epsilon) || (v > 1 + Path2D.Epsilon))
{
return(null);
}
// get intersection point
Point2D ip = path.GetCreatePoint(p1.x + u * x21, p1.y + u * y21);
segments = new List <Segment2D>();
// if ip is not on edge of lines, split them
if (!Object.ReferenceEquals(p1, ip) && !Object.ReferenceEquals(p2, ip))
{
segments.AddRange(SplitAt(ip));
}
else
{
segments.Add(this);
}
if (!Object.ReferenceEquals(seg.p1, ip) && !Object.ReferenceEquals(seg.p2, ip))
{
segments.AddRange(seg.SplitAt(ip));
}
else
{
segments.Add(seg);
}
return(segments);
}
