public Edge CreateEdge(Point lSite, Point rSite, Point va, Point vb)
{
Edge edge = new Edge(lSite, rSite);
this.edges.Add(edge);
if (va)
{
edge.SetStartPoint(lSite, rSite, va);
}
if (vb)
{
edge.SetEndPoint(lSite, rSite, vb);
}
this.cells[lSite.id].halfEdges.Add(new HalfEdge(edge, lSite, rSite));
this.cells[rSite.id].halfEdges.Add(new HalfEdge(edge, rSite, lSite));
return edge;
}
// ---------------------------------------------------------------------------
// Diagram completion methods
// connect dangling edges (not if a cursory test tells us
// it is not going to be visible.
// return value:
// false: the dangling va couldn't be connected
// true: the dangling va could be connected
public bool ConnectEdge(Edge edge, Bounds bbox)
{
// skip if end point already connected
Point vb = edge.vb;
if (!!vb)
{
return true;
}
// make local copy for performance purpose
Point va = edge.va;
float xl = bbox.min.x;
float xr = bbox.max.x;
float yt = bbox.min.z;
float yb = bbox.max.z;
Point lSite = edge.lSite;
Point rSite = edge.rSite;
float lx = lSite.x;
float ly = lSite.y;
float rx = rSite.x;
float ry = rSite.y;
float fx = (lx + rx) / 2;
float fy = (ly + ry) / 2;
float fm = float.NaN;
float fb = 0.0f;
// if we reach here, this means cells which use this edge will need
// to be closed, whether because the edge was removed, or because it
// was connected to the bounding box.
this.cells[lSite.id].closeMe = true;
this.cells[rSite.id].closeMe = true;
// get the line equation of the bisector if line is not vertical
if (ry != ly)
{
fm = (lx - rx) / (ry - ly);
fb = fy - fm * fx;
}
// remember, direction of line (relative to left site):
// upward: left.x < right.x
// downward: left.x > right.x
// horizontal: left.x == right.x
// upward: left.x < right.x
// rightward: left.y < right.y
// leftward: left.y > right.y
// vertical: left.y == right.y
// depending on the direction, find the best side of the
// bounding box to use to determine a reasonable start point
// rhill 2013-12-02:
// While at it, since we have the values which define the line,
// clip the end of va if it is outside the bbox.
// https://github.com/gorhill/Javascript-Voronoi/issues/15
// TODO: Do all the clipping here rather than rely on Liang-Barsky
// which does not do well sometimes due to loss of arithmetic
// precision. The code here doesn't degrade if one of the vertex is
// at a huge distance.
// special case: vertical line
if (float.IsNaN(fm))
{
// doesn't intersect with viewport
if (fx < xl || fx >= xr)
{
return false;
}
// downward
if (lx > rx)
{
if (!va || va.y < yt)
{
//Debug.Log(yt);
va = new Point(fx, yt);
}
else if (va.y >= yb)
{
//Debug.Log(yb);
return false;
}
vb = new Point(fx, yb);
}
// upward
else
{
if (!va || va.y > yb)
{
//Debug.Log(yb);
va = new Point(fx, yb);
}
else if (va.y < yt)
{
//Debug.Log(yt);
return false;
}
vb = new Point(fx, yt);
}
}
// closer to vertical than horizontal, connect start point to the
// top or bottom side of the bounding box
else if (fm < -1 || fm > 1)
{
// downward
if (lx > rx)
{
if (!va || va.y < yt)
{
//Debug.Log(va.y + " yt: " + yt);
va = new Point((yt - fb) / fm, yt);
}
else if (va.y >= yb)
{
//Debug.Log(va.y + " yb: " + yb);
return false;
}
vb = new Point((yb - fb) / fm, yb);
}
// upward
else
{
if (!va || va.y > yb)
{
//Debug.Log(va.y + " yb: " + yb);
va = new Point((yb - fb) / fm, yb);
}
else if (va.y < yt)
{
//Debug.Log(va.y + " yt: " + yt);
return false;
}
vb = new Point((yt - fb) / fm, yt);
}
}
// closer to horizontal than vertical, connect start point to the
// left or right side of the bounding box
else
{
// rightward
if (ly < ry)
{
if (!va || va.x < xl)
{
//Debug.Log(va.x + " xl: " + xl);
va = new Point(xl, fm * xl + fb);
}
else if (va.x >= xr)
{
//Debug.Log(va.x + " xr: " + xr);
return false;
}
vb = new Point(xr, fm * xr + fb);
}
// leftward
else
{
if (!va || va.x > xr)
{
//Debug.Log(va.x + " xr: " + xr);
va = new Point(xr, fm * xr + fb);
}
else if (va.x < xl)
{
//Debug.Log(va.x + " xl: " + xl);
return false;
}
vb = new Point(xl, fm * xl + fb);
}
}
edge.va = va;
edge.vb = vb;
return true;
}
public Edge CreateBorderEdge(Point lSite, Point va, Point vb)
{
Edge edge = new Edge(lSite, null);
edge.va = va;
edge.vb = vb;
this.edges.Add(edge);
return edge;
}
// line-clipping code taken from:
// Liang-Barsky function by Daniel White
// http://www.skytopia.com/project/articles/compsci/clipping.html
// Thanks!
// A bit modified to minimize code paths
public bool ClipEdge(Edge edge, Bounds bbox)
{
float ax = edge.va.x;
float ay = edge.va.y;
float bx = edge.vb != null ? edge.vb.x : float.NaN;
float by = edge.vb != null ? edge.vb.y : float.NaN;
float t0 = 0;
float t1 = 1;
float dx = bx - ax;
float dy = by - ay;
// left
float q = ax - bbox.min.x;
if (dx == 0 && q < 0) { return false; }
float r = -q / dx;
if (dx < 0)
{
if (r < t0) { return false; }
if (r < t1) { t1 = r; }
}
else if (dx > 0)
{
if (r > t1) { return false; }
if (r > t0) { t0 = r; }
}
// right
q = bbox.max.x - ax;
if (dx == 0 && q < 0) { return false; }
r = q / dx;
if (dx < 0)
{
if (r > t1) { return false; }
if (r > t0) { t0 = r; }
}
else if (dx > 0)
{
if (r < t0) { return false; }
if (r < t1) { t1 = r; }
}
// top
q = ay - bbox.min.z;
if (dy == 0 && q < 0) { return false; }
r = -q / dy;
if (dy < 0)
{
if (r < t0) { return false; }
if (r < t1) { t1 = r; }
}
else if (dy > 0)
{
if (r > t1) { return false; }
if (r > t0) { t0 = r; }
}
// bottom
q = bbox.max.z - ay;
if (dy == 0 && q < 0) { return false; }
r = q / dy;
if (dy < 0)
{
if (r > t1) { return false; }
if (r > t0) { t0 = r; }
}
else if (dy > 0)
{
if (r < t0) { return false; }
if (r < t1) { t1 = r; }
}
// if we reach this point, Voronoi edge is within bbox
// if t0 > 0, va needs to change
// rhill 2011-06-03: we need to create a new vertex rather
// than modifying the existing one, since the existing
// one is likely shared with at least another edge
if (t0 > 0)
{
edge.va = new Point(ax + t0 * dx, ay + t0 * dy);
}
// if t1 < 1, vb needs to change
// rhill 2011-06-03: we need to create a new vertex rather
// than modifying the existing one, since the existing
// one is likely shared with at least another edge
if (t1 < 1)
{
edge.vb = new Point(ax + t1 * dx, ay + t1 * dy);
}
// va and/or vb were clipped, thus we will need to close
// cells which use this edge.
if (t0 > 0 || t1 < 1)
{
this.cells[edge.lSite.id].closeMe = true;
this.cells[edge.rSite.id].closeMe = true;
}
return true;
}
