public bool isTowerOnPath(TDTower t)
{
// first check if intersting any corner
TDPathPoint lastPoint = null;
foreach (TDPath p in this.Paths)
{
foreach (TDPathPoint pp in p.PathPoints)
{
if (TDMath.Intersects(t.Location, t.Size, pp.Location, GridSize))
{
return(true);
}
else
{
// check intersecting any line
if (lastPoint != null)
{
if (TDMath.Intersects(t, pp, lastPoint))
{
return(true);
}
}
lastPoint = pp;
}
}
}
return(false);
}
/// <summary>
/// Does the target interect the line between point A and point B.
/// </summary>
/// <param name="target"></param>
/// <param name="pointA"></param>
/// <param name="pointB"></param>
/// <returns></returns>
internal static bool Intersects(TDTower target, TDPathPoint pointA, TDPathPoint pointB)
{
bool result = false;
// adjust PathPoints by GridSize
double aX = pointA.Location.X;
double aY = pointA.Location.Y;
double bX = pointB.Location.X;
double bY = pointB.Location.Y;
bool intersectXAxis = false;
bool intersectYAxis = false;
if (aX < bX)
{
intersectXAxis = target.Location.X <bX + (TDMap.GridSize - 2) && target.Location.X + (TDMap.GridSize - 2)> aX;
}
else
{
intersectXAxis = target.Location.X <aX + (TDMap.GridSize - 2) && target.Location.X + (TDMap.GridSize - 2)> bX;
}
// y between
if (aY < bY)
{
intersectYAxis = target.Location.Y <bY + (TDMap.GridSize - 2) && target.Location.Y + (TDMap.GridSize - 2)> aY;
}
else
{
intersectYAxis = target.Location.Y <aY + (TDMap.GridSize - 2) && target.Location.Y + (TDMap.GridSize - 2)> bY;
}
// if it intersects the rectangle of the two
result = intersectXAxis && intersectYAxis;
// if it is within the square box, and is a diagonal line, check it additionally because it might not be on the actual path.
if (result &&
aX != bX && aY != bY) // neither a horizontal or vertical line
{
// use graphing formulas y=Mx+b to see if the location is on the line (or within range of the line).
// y = (Mx + b)
// y = ((^Y / ^X) * x + b)
// target.y = ((changeY / changeX)* target.x + b)
// target.y = (((bY-aY) / (bX-aX))* target.x + b))
double slope = (bY - aY) / (bX - aX);
// to find b, use b = y - mx, and we put in one of the points
double b = aY - (slope * aX);
double estimatedY = slope * target.Location.X + b;
// actual Y needs to be 'close' to the estimated Y of the line
result = (Math.Abs(target.Location.Y - estimatedY) < (TDMap.GridSize - 1));
}
return(result);
}
private void DrawPaths(Graphics g)
{
foreach (TDPath p in Paths)
{
TDPathPoint lastPoint = null;
foreach (TDPathPoint pp in p.PathPoints)
{
if (lastPoint == null)
{
// don't draw the first point
lastPoint = pp;
continue;
}
try
{
// draw a line from this point back to our last point.
g.DrawLine(pathPen, (int)lastPoint.Location.X, (int)lastPoint.Location.Y, (int)pp.Location.X, (int)pp.Location.Y);
// draw the last point differently (the base).
if (pp == p.PathPoints[p.PathPoints.Count - 1])
{
// draw the base
if (BaseImage != null)
{
g.DrawImage(BaseImage, (int)(pp.Location.X - (BaseImage.Width / 2) + 1), (int)(pp.Location.Y - (BaseImage.Width / 2) + 1), BaseImage.Width, BaseImage.Width);
}
else
{
g.FillRectangle(BaseBrush, (int)(pp.Location.X - (pathPen.Width / 2) + 1), (int)(pp.Location.Y - (pathPen.Width / 2) + 1), pathPen.Width, pathPen.Width);
}
}
else
{
// draw this point, specifically (catches the corners of the path)
g.FillEllipse(pathPen.Brush, (int)(pp.Location.X - (pathPen.Width / 2)), (int)(pp.Location.Y - (pathPen.Width / 2)), pathPen.Width, pathPen.Width);
}
}
catch { } // just skip drawing during this frame (no need to get picky)
// reset who is the last point
lastPoint = pp;
}
}
}