public static Collision2? FindCollision(Rectangle2 rectangle, Vector2 movement, Line2 line)
{
if (Vector2.Dot(movement, line.Normal()) >= 0)
return null;
var h = InFrontOf(rectangle.Center, line);
var j = InFrontOf(rectangle.Center + movement, line);
if (!h && !j)
return null;
var f1 = LineSegmentIntersection(line.Start, line.End, rectangle.TopLeft, rectangle.TopLeft + movement);
var f2 = LineSegmentIntersection(line.Start, line.End, rectangle.TopRight, rectangle.TopRight + movement);
var f3 = LineSegmentIntersection(line.Start, line.End, rectangle.BottomLeft, rectangle.BottomLeft + movement);
var f4 = LineSegmentIntersection(line.Start, line.End, rectangle.BottomRight, rectangle.BottomRight + movement);
if (!f1.HasValue && !f2.HasValue && !f3.HasValue && !f4.HasValue)
return null;
f1 = LinesIntersection(line.Start, line.End, rectangle.TopLeft, rectangle.TopLeft + movement);
f2 = LinesIntersection(line.Start, line.End, rectangle.TopRight, rectangle.TopRight + movement);
f3 = LinesIntersection(line.Start, line.End, rectangle.BottomLeft, rectangle.BottomLeft + movement);
f4 = LinesIntersection(line.Start, line.End, rectangle.BottomRight, rectangle.BottomRight + movement);
List<float> fs = new List<float>();
if ((Vector2.Dot(rectangle.Top.Normal(), line.Normal()) <= 0) && (Vector2.Dot(rectangle.Left.Normal(), line.Normal()) <= 0))
fs.Add(f1.Value);
if ((Vector2.Dot(rectangle.Top.Normal(), line.Normal()) <= 0) && (Vector2.Dot(rectangle.Right.Normal(), line.Normal()) <= 0))
fs.Add(f2.Value);
if ((Vector2.Dot(rectangle.Bottom.Normal(), line.Normal()) <= 0) && (Vector2.Dot(rectangle.Left.Normal(), line.Normal()) <= 0))
fs.Add(f3.Value);
if ((Vector2.Dot(rectangle.Bottom.Normal(), line.Normal()) <= 0) && (Vector2.Dot(rectangle.Right.Normal(), line.Normal()) <= 0))
fs.Add(f4.Value);
var array = fs.OrderBy(x => x);
if (!array.Any())
return null;
if (array.Last() < 0)
return null;
if (array.First() > 1)
return null;
Collision2 collision = new Collision2();
collision.Value = MinLinesIntersection(rectangle, movement, line);
collision.Line = line;
return collision;
}
public static Vector2? FindCollision(Rectangle2 rectangle, Line2 line)
{
var f1 = SegmentsIntersection(rectangle.Top, line);
var f2 = SegmentsIntersection(rectangle.Left, line);
var f3 = SegmentsIntersection(rectangle.Right, line);
var f4 = SegmentsIntersection(rectangle.Bottom, line);
if (!f1.HasValue && !f2.HasValue && !f3.HasValue && !f4.HasValue)
return null;
var d = Math.Min(Math.Min(Distance(rectangle.TopLeft, line), Distance(rectangle.TopRight, line)), Math.Min(Distance(rectangle.BottomLeft, line), Distance(rectangle.BottomRight, line)));
return -line.Normal() * d * 1.01f;
}
public bool IsGrounded(Rectangle2 rectangle)
{
var groundGeometry = GetCollisionGeometry().Where(x => x.Normal().Y > 0.5f);
return CollisionDetector.FindCollision(rectangle + CollisionDetector.GetStaticCollisionResolvingVector(rectangle, groundGeometry), new Vector2(0, -0.1f), groundGeometry).HasValue;
}
public Vector2 GetFinalVelocity(Rectangle2 rectangle, Vector2 velocity)
{
return CollisionDetector.GetFinalMovement(rectangle, velocity, GetCollisionGeometry());
}
public Vector2 GetCollisionResolvingVector(Rectangle2 rectangle)
{
return CollisionDetector.GetStaticCollisionResolvingVector(rectangle, GetCollisionGeometry());
}
private static float MinLinesIntersection(Rectangle2 rectangle, Vector2 movement, Line2 line)
{
return Math.Min(
Math.Min(
LinesIntersection(rectangle.TopLeft, rectangle.TopLeft + movement, line.Start, line.End) ?? 1f,
LinesIntersection(rectangle.TopRight, rectangle.TopRight + movement, line.Start, line.End) ?? 1f),
Math.Min(
LinesIntersection(rectangle.BottomLeft, rectangle.BottomLeft + movement, line.Start, line.End) ?? 1f,
LinesIntersection(rectangle.BottomRight, rectangle.BottomRight + movement, line.Start, line.End) ?? 1f));
}
public static bool Collides(Rectangle2 rectangle, Vector2 movement, Line2 line)
{
return FindCollision(rectangle, movement, line).HasValue;
}
public static Vector2 GetStaticCollisionResolvingVector(Rectangle2 rectangle, IEnumerable<Line2> lines)
{
var staticCollisionResolvingVector = Vector2.Zero;
foreach (var line in lines)
{
var partial = CollisionDetector.FindCollision(rectangle, line);
if (partial.HasValue)
staticCollisionResolvingVector = staticCollisionResolvingVector + partial.Value;
}
return staticCollisionResolvingVector;
}
public static Vector2 GetFinalMovement(Rectangle2 rectangle, Vector2 movement, IEnumerable<Line2> lines)
{
float damp = 0.99f;
var v = movement;
var v2 = Vector2.Zero;
var step = rectangle;
var collision = CollisionDetector.FindCollision(step, v, lines);
while (collision.HasValue)
{
if (collision.Value.Value < 0)
break;
v2 += v * collision.Value.Value * damp;
step = step + v * collision.Value.Value * damp;
//step = step + CollisionDetector.GetStaticCollisionResolvingVector(step, lines);
v = GetSlidingVector(v, collision.Value.Line.Direction(), collision.Value.Value) * damp;
collision = CollisionDetector.FindCollision(step, v, lines);
}
return v2 + v;
}
public static Vector2 FindMaxMovement(Rectangle2 rectangle, Vector2 movement, IEnumerable<Line2> lines)
{
var collision = FindCollision(rectangle, movement, lines);
if (collision.HasValue)
return movement * collision.Value.Value;
else
return movement;
}
public static Collision2? FindCollision(Rectangle2 rectangle, Vector2 movement, IEnumerable<Line2> lines)
{
var collisions = lines.Select(x => FindCollision(rectangle, movement, x)).Where(x => x.HasValue);
if (collisions.Any())
return collisions.OrderBy(x => x.Value.Value).First();
else
return null;
}
