public LineSegment(Point point1, Point point2)
{
this.point1 = point1.ToVector2();
this.point2 = point2.ToVector2();
if (point1.X <= point2.X)
{
minX = point1.X;
maxX = point2.X;
}
else
{
minX = point2.X;
maxX = point1.X;
}
if (point1.Y <= point2.Y)
{
minY = point1.Y;
maxY = point2.Y;
}
else
{
minY = point2.Y;
maxY = point1.Y;
}
equation = new LineEquation(this);
}
public LineSegment(float x1, float y1, float x2, float y2)
{
point1 = new Vector2((float)Math.Round(x1, 5), (float)Math.Round(y1, 5));
point2 = new Vector2((float)Math.Round(x2, 5), (float)Math.Round(y2, 5));
if (x1 <= x2)
{
minX = point1.X;
maxX = point2.X;
}
else
{
minX = point2.X;
maxX = point1.X;
}
if (y1 <= y2)
{
minY = point1.Y;
maxY = point2.Y;
}
else
{
minY = point2.Y;
maxY = point1.Y;
}
equation = new LineEquation(this);
}
public List <Vector2> getIntercepts(LineEquation equation)
{
List <Vector2> intercepts = new List <Vector2>();
if ((vertical && equation.vertical) || (slope == equation.slope))
{
//either exact same line or no intersections
return(intercepts);
}
if (vertical)
{
//this is vertical. other eq is not. get y from other eq where x = this eq's x
intercepts.Add(new Vector2(x, equation.slope * x + equation.yIntercept));
}
else if (equation.vertical)
{
//other eq is vertical. this is not. get y from this eq where x = other eq's x
intercepts.Add(new Vector2(equation.x, slope * equation.x + yIntercept));
}
else
{
// lines are oblique
// y1 = m1 * x1 + b1
// y2 = m2 * x2 + b2
//
// set ys equal to each other and solve for x
// m1 * x + b1 = m2 * x + b2
// (m1 * x) - (m2 * x) = b2 - b1
// x * (m1 - m2) = b2 - b1
// x = (b2 - b1) / (m1 - m2)
//
// shove x back into original eq to get y
float interceptX = (equation.yIntercept - yIntercept) / (slope - equation.slope);
float interceptY = slope * interceptX + yIntercept;
intercepts.Add(new Vector2(interceptX, interceptY));
}
return(intercepts);
}
