} //testPolygonVsPolygon
/** Internal api - test a ray against a circle */
public static bool TestRayVsCircle(Ray ray, Circle circle, out RayCollision rayCollision)
{
Vector2 delta = ray.End - ray.Start;
Vector2 ray2Circle = ray.Start - circle.Position;
float a = delta.LengthSquared();
float b = 2 * Vector2.Dot(delta, ray2Circle);
float c = Vector2.Dot(ray2Circle, ray2Circle) - (circle.Radius * circle.Radius);
float d = b * b - 4 * a * c;
if (d >= 0)
{
d = (float)System.Math.Sqrt(d);
float t1 = (-b - d) / (2 * a);
float t2 = (-b + d) / (2 * a);
if (ray.IsInfinite || (t1 <= 1.0 && t1 >= 0.0))
{
rayCollision = new RayCollision
{
Shape = circle,
Ray = ray,
Start = t1,
End = t2
};
return(true);
} //
} //d >= 0
rayCollision = new RayCollision();
return(false);
}
/** Internal api - test a ray against a polygon */
public static bool TestRayVsPolygon(Ray ray, Polygon polygon, out RayCollision rayCollision)
{
float minU = float.PositiveInfinity;
float maxU = 0.0f;
float startX = ray.Start.X;
float startY = ray.Start.Y;
float deltaX = ray.End.X - startX;
float deltaY = ray.End.Y - startY;
var verts = polygon.TransformedVertices;
Vector2 v1 = verts[^ 1];
