/// <summary>
/// Creates a new circle collider with the given position and radius.
/// </summary>
/// <param name="position">the center of the circle</param>
/// <param name="radius">the radius of the circle</param>
public DCircleCollider(Vector2F position, Fix32 radius, bool isTrigger) : base(ColliderType.Circle, isTrigger)
{
this.center = position;
this.radius = radius;
Vector2F min = center - Vector2F.One * radius;
Vector2F max = center + Vector2F.One * radius;
boundingBox = new DBoxCollider(min, max, isTrigger);
}
public bool Intersects(DCollider collider)
{
DBoxCollider bbox = (collider.Type == ColliderType.Box) ? (DBoxCollider)collider : ((DCircleCollider)collider).BoundingBox;
Vector2F min = position;
Vector2F max = position + Vector2F.One * size;
if (max.x < bbox.Min.x || min.x > bbox.Max.x)
{
return(false);
}
if (max.y < bbox.Min.y || min.y > bbox.Max.y)
{
return(false);
}
return(true);
}
/// <summary>
/// Removes the given object from the grid.
/// </summary>
/// <param name="obj">the rigid body</param>
public void Remove(DBody obj)
{
DBoxCollider box = obj.Collider.GetContainer();
Coord min = Hash(box.Min);
Coord max = Hash(box.Max);
if (!IsInsideBounds(min) || !IsInsideBounds(max))
{
return;
}
for (int i = min.x; i <= max.x; i++)
{
for (int j = min.y; j <= max.y; j++)
{
Remove(obj, i, j);
}
}
}
/// <summary>
/// Checks whether the given box collider intersects with this circle, calculating
/// the collision data in that case.
/// </summary>
/// <param name="other">box collider to check</param>
/// <param name="intersection">the collision data, <code>null</code> if no collision has been detected.</param>
/// <returns>true if the colliders intersect, false otherwise.</returns>
public override bool Intersects(DBoxCollider other, out Manifold intersection)
{
intersection = null;
Vector2F halfExtents = other.GetExtents() / 2;
Vector2F boxCenter = other.Min + halfExtents;
Vector2F difference = center - boxCenter;
Vector2F clamped = Vector2F.Clamp(difference, -halfExtents, halfExtents);
Vector2F closest = boxCenter + clamped;
difference = closest - center;
if (difference.SqrtMagnitude > radius * radius)
{
return(false);
}
//check if one of them is a trigger
if (this.IsTrigger || other.IsTrigger)
{
intersection = new Manifold(this.Body, other.Body);
return(true);
}
Fix32 dist = difference.Magnitude;
Fix32 penetration;
Vector2F normal;
if (dist > Fix32.Zero)
{
penetration = radius - dist;
normal = difference / dist;
}
else
{
penetration = radius;
normal = new Vector2F(1, 0);
}
intersection = new Manifold(this.Body, other.Body, normal, penetration);
return(true);
}
public override bool Intersects(DBoxCollider other, out Manifold intersection)
{
throw new NotImplementedException();
}
/// <summary>
/// Checks whether the two boxes collide, generating an intersection containing the collision data.
/// This function can only compare bounding boxes againsts other bounding boxes.
/// </summary>
/// <param name="other">bounding box to check</param>
/// <param name="intersection">the collision data, <code>null</code> if no collision has been detected.</param>
/// <returns></returns>
public override bool Intersects(DBoxCollider other, out Manifold intersection)
{
intersection = null;
//check if one of them is a trigger
if (this.IsTrigger || other.IsTrigger)
{
intersection = new Manifold(this.Body, other.Body);
return(true);
}
// Vector from A to B
Vector2F distance = other.Body.Position - Body.Position;
// Calculate half extents along x axis for each object
Fix32 xEntentA = (max.x - min.x) / (Fix32)2;
Fix32 xExtentB = (other.max.x - other.min.x) / (Fix32)2;
// Calculate overlap on x axis
Fix32 offsetX = xEntentA + xExtentB - Fix32.Abs(distance.x);
// SAT test on x axis
if (offsetX > Fix32.Zero)
{
// Calculate half extents along x axis for each object
Fix32 yExtentA = (max.y - min.y) / (Fix32)2;
Fix32 yExtentB = (other.max.y - other.min.y) / (Fix32)2;
// Calculate overlap on y axis
Fix32 offsetY = yExtentA + yExtentB - Fix32.Abs(distance.y);
// SAT test on y axis
if (offsetY > Fix32.Zero)
{
Vector2F n;
// Find out which axis is axis of least penetration
if (offsetX < offsetY)
{
// Point towards B knowing that n points from A to B
if (distance.x < Fix32.Zero)
{
n = new Vector2F(-1, 0);
}
else
{
n = new Vector2F(1, 0);
}
intersection = new Manifold(Body, other.Body, n, offsetX);
return(true);
}
else
{
// Point toward B knowing that n points from A to B
if (distance.y < Fix32.Zero)
{
n = new Vector2F(0, -1);
}
else
{
n = new Vector2F(0, 1);
}
intersection = new Manifold(Body, other.Body, n, offsetY);
return(true);
}
}
}
return(false);
}
/// <summary> /// Abstract function for intersections with boxes. /// </summary> /// <param name="other">box collider.</param> /// <param name="intersection">collision data.</param> /// <returns></returns> public abstract bool Intersects(DBoxCollider other, out Manifold intersection);
