public IEnumerable<Tuple<Point2l, Point2l>> Trace(Point2l start, Point2l end)
{
var x0 = start.X / GridSize.Width;
var y0 = start.Y / GridSize.Height;
var x1 = end.X / GridSize.Width;
var y1 = end.Y / GridSize.Height;
var dir = new Vector2l(end.X - start.X, end.Y - start.Y);
var dx = Math.Sign(dir.X);
var dy = Math.Sign(dir.Y);
var deltax = (double)GridSize.Width / Math.Abs(dir.X);
var deltay = (double)GridSize.Height / Math.Abs(dir.Y);
var minx = x0 * GridSize.Width;
var maxx = minx + GridSize.Width;
var miny = y0 * GridSize.Height;
var maxy = miny + GridSize.Height;
var distx = ((dx >= 0) ? (maxx - start.X) : (start.X - minx)) / (double)GridSize.Width;
var disty = ((dy >= 0) ? (maxy - start.Y) : (start.Y - miny)) / (double)GridSize.Height;
var tx = distx * deltax;
var ty = disty * deltay;
var prev = new Point2l(x0, y0);
var hit = start;
while (true)
{
var grid = new Point2l(x0, y0);
yield return Tuple.Create(grid, hit);
prev = grid;
if (tx <= ty)
{
if (x0 == x1) break;
hit = new Point2l(
start.X + (long)(dir.X * tx),
start.Y + (long)(dir.Y * tx));
tx += deltax;
x0 += dx;
}
else
{
if (y0 == y1) break;
hit = new Point2l(
start.X + (long)(dir.X * ty),
start.Y + (long)(dir.Y * ty));
ty += deltay;
y0 += dy;
}
}
}
public IEnumerable <Tuple <Point2l, Point2l> > Trace(Point2l start, Point2l end)
{
var x0 = start.X / GridSize.Width;
var y0 = start.Y / GridSize.Height;
var x1 = end.X / GridSize.Width;
var y1 = end.Y / GridSize.Height;
var dir = new Vector2l(end.X - start.X, end.Y - start.Y);
var dx = Math.Sign(dir.X);
var dy = Math.Sign(dir.Y);
var deltax = (double)GridSize.Width / Math.Abs(dir.X);
var deltay = (double)GridSize.Height / Math.Abs(dir.Y);
var minx = x0 * GridSize.Width;
var maxx = minx + GridSize.Width;
var miny = y0 * GridSize.Height;
var maxy = miny + GridSize.Height;
var distx = ((dx >= 0) ? (maxx - start.X) : (start.X - minx)) / (double)GridSize.Width;
var disty = ((dy >= 0) ? (maxy - start.Y) : (start.Y - miny)) / (double)GridSize.Height;
var tx = distx * deltax;
var ty = disty * deltay;
var prev = new Point2l(x0, y0);
var hit = start;
while (true)
{
var grid = new Point2l(x0, y0);
yield return(Tuple.Create(grid, hit));
prev = grid;
if (tx <= ty)
{
if (x0 == x1)
{
break;
}
hit = new Point2l(
start.X + (long)(dir.X * tx),
start.Y + (long)(dir.Y * tx));
tx += deltax;
x0 += dx;
}
else
{
if (y0 == y1)
{
break;
}
hit = new Point2l(
start.X + (long)(dir.X * ty),
start.Y + (long)(dir.Y * ty));
ty += deltay;
y0 += dy;
}
}
}
