// BOURKE INTERSECT ALGORITHM
public bool intersects(LineSeg line)
{
double denom = (line.B.Y - line.A.Y) * (this.B.X - this.A.X)
-
(line.B.X - line.A.X) * (this.B.Y - this.A.Y);
double numA = (line.B.X - line.A.X) * (this.A.Y - line.A.Y)
-
(line.B.Y - line.A.Y) * (this.A.X - line.A.X);
double numB = (this.B.X - this.A.X) * (this.A.Y - line.A.Y)
-
(this.B.Y - this.A.Y) * (this.A.X - line.A.X);
//check for parallel and div by 0
if (denom == 0d)
{
return(false);
}
double uA = numA / denom;
double uB = numB / denom;
if (uA >= 0d && uA <= 1d && uB >= 0d && uB <= 1d)
{
return(true);
}
return(false);
}
private void updateLines()
{
lines = new LineSeg[points.Length];
for (int i = 0; i < points.Length - 1; i++)
{
lines[i] = new LineSeg(points [i], points [i + 1]);
}
lines [lines.Length - 1] = new LineSeg(points [0], points [points.Length - 1]);
}
private bool raytrace(Vector2 source, Vector2 destination)
{
int intersects = 0;
LineSeg checkLine = new LineSeg(source, destination);
foreach (LineSeg line in lines)
{
if (checkLine.intersects(line))
{
intersects++;
}
}
return(intersects % 2 == 1);
}
public static void line(SpriteBatch spriteBatch, Vector2 start, Vector2 end, Color colour)
{
LineSeg line = new LineSeg(start, end);
spriteBatch.Draw(tex, new Rectangle((int)line.A.X, (int)line.A.Y, (int)line.length(), 5), null, colour, line.angle(), new Vector2(0F, 0F), SpriteEffects.None, 1f);
}
