/// <summary>
/// Check and create collision info between a circle and AABB collider.
/// </summary>
/// <param name="_circle"></param>
/// <param name="_aabb"></param>
private void Circle_AABB(ABCircleCollider _circle, ABBoxCollider _aabb)
{
AABB_Circle(_aabb, _circle);
// because pair order gets flipped here, the normal also needs to be flipped.
Normal = -Normal;
}
/// <summary>
/// Check and create collision info for two given circle colliders.
/// </summary>
/// <param name="_circle1"></param>
/// <param name="_circle2"></param>
private void Circle_Circle(ABCircleCollider _circle1, ABCircleCollider _circle2)
{
var normal = _circle2.Position - _circle1.Position;
var distSqr = normal.sqrMagnitude;
var radiusSum = _circle1.Radius + _circle2.Radius;
if (distSqr >= radiusSum * radiusSum)
{
ContactDetected = false;
return;
}
ContactDetected = true;
var distance = Mathf.Sqrt(distSqr);
if (distance == 0.0f)
{
Penetration = _circle1.Radius;
Normal = Vector2.up;
}
else
{
Penetration = radiusSum - distance;
Normal = normal.normalized;
}
}
/// <summary>
/// Check and create collision info between an AABB and circle collider.
/// </summary>
/// <param name="_aabb"></param>
/// <param name="_circle"></param>
private void AABB_Circle(ABBoxCollider _aabb, ABCircleCollider _circle)
{
_aabb.ComputeAABB();
var xNear = Mathf.Max(_aabb.Min.x, Mathf.Min(_circle.Position.x, _aabb.Max.x));
var yNear = Mathf.Max(_aabb.Max.y, Mathf.Min(_circle.Position.y, _aabb.Min.y));
var closesPointToRect = new Vector2(xNear, yNear);
var normal = _circle.Position - closesPointToRect;
if (normal.sqrMagnitude < _circle.Radius * _circle.Radius)
{
// Collision between the circle and aabb.
ContactDetected = true;
Penetration = _circle.Radius - normal.magnitude;
Normal = normal.normalized;
}
}