//**********************************************************
//** methods:
//**********************************************************
public Vector2f?Intersects(FloatLine line)
{
var x1 = line.P1.X;
var y1 = line.P1.Y;
var x2 = line.P2.X;
var y2 = line.P2.Y;
var x3 = P1.X;
var y3 = P1.Y;
var x4 = P2.X;
var y4 = P2.Y;
var den = (x1 - x2) * (y3 - y4) - (y1 - y2) * (x3 - x4);
if (den == 0)
{
return(null);
}
var t = ((x1 - x3) * (y3 - y4) - (y1 - y3) * (x3 - x4)) / den;
var u = -((x1 - x2) * (y1 - y3) - (y1 - y2) * (x1 - x3)) / den;
if (t > 0 && t < 1 && u > 0)
{
return(new Vector2f(
x1 + (t * (x2 - x1)),
y1 + (t * (y2 - y1))
));
}
return(null);
}
private Vector2f[] IntersectionPoints(FloatLine ray, RectangleShape shape)
{
var l1 = new FloatLine(shape.Position, shape.Position + new Vector2f(shape.Size.X, 0));
var l2 = new FloatLine(shape.Position, shape.Position + new Vector2f(0, shape.Size.Y));
var l3 = new FloatLine(
shape.Position.X,
shape.Position.Y + shape.Size.Y,
shape.Position.X + shape.Size.X,
shape.Position.Y + shape.Size.Y
);
var l4 = new FloatLine(
shape.Position.X + shape.Size.X,
shape.Position.Y,
shape.Position.X + shape.Size.X,
shape.Position.Y + shape.Size.Y
);
var intersections = new List <Vector2f?>
{
ray.Intersects(l1),
ray.Intersects(l2),
ray.Intersects(l3),
ray.Intersects(l4),
};
return(intersections
.Where(x => x != null)
.Cast <Vector2f>()
.ToArray());
}
private Vector2f[] IntersectionPoints(FloatLine ray, LineShape shape)
{
var line = new FloatLine(shape.P1, shape.P2);
var intersectionPoint = ray.Intersects(line);
return(intersectionPoint.HasValue ? new[] { intersectionPoint.Value } : new Vector2f[0]);
}
public static TwoPointForm GetTwoPointForm(FloatLine line)
{
var x1 = line.P1.X;
var y1 = line.P1.Y;
var x2 = line.P2.X;
var y2 = line.P2.Y;
var m = Slope(x1, y1, x2, y2);
return(new TwoPointForm {
M = m, X1 = x1, Y1 = y1
});
}
public static SlopeInterceptForm GetSlopeInterceptForm(FloatLine line)
{
var x1 = line.P1.X;
var y1 = line.P1.Y;
var x2 = line.P2.X;
var y2 = line.P2.Y;
var m = Slope(x1, y1, x2, y2);
var b = -(m * x1) + y1;
return(new SlopeInterceptForm {
M = m, B = b
});
}
private Vector2f[] IntersectionPoints(FloatLine ray, CircleShape shape)
{
var circle = new FloatCircle(shape.Position, shape.Radius);
var circleDelta = (shape.Position - Position);
var product = Direction.Dot(circleDelta);
if (product <= 0) // if ray is facing in the opposite direction of the circle
{
return(Array.Empty <Vector2f>());
}
return(ray.Intersects(circle));
}
private Vector2f[] IntersectionPoints(FloatLine ray, Shape shape)
{
switch (shape)
{
case LineShape line:
return(IntersectionPoints(ray, line));
case CircleShape circle:
return(IntersectionPoints(ray, circle));
case RectangleShape rect:
return(IntersectionPoints(ray, rect));
default:
throw new NotImplementedException("Shape intersection not implemented");
}
}
public Vector2f?Cast(Shape[] shapes)
{
var p1 = Position;
var p2 = Position + (Direction * 100_000_000f);
var ray = new FloatLine(p1, p2);
var intersectionPoints
= shapes.SelectMany(shape => IntersectionPoints(ray, shape));
if (!intersectionPoints.Any())
{
return(null);
}
return(intersectionPoints
.Select(point => (point, (point - Position).SqrLength()))
.Aggregate((shortest, x) => x.Item2 < shortest.Item2 ? x : shortest).point);
}
public Vector2f Reflect(FloatLine mirror)
{
var n = mirror.NormalDirection();
return(Direction().Reflect(n));
}
public static Vector2f Reflect(this Vector2f vec, FloatLine mirror)
{
return(vec.Reflect(mirror.NormalDirection()));
}
public static Vector2f NormalDirection(this FloatLine line)
{
return(NormalDirection(line.P1, line.P2));
}
public static FloatLine Normal(this FloatLine line)
{
var normal = Normal(line.P1, line.P2);
return(new FloatLine(normal.Item1, normal.Item2));
}