/// <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 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;
}
}
/// <summary>
/// Check and create collison info for two given AABB colliders.
/// </summary>
/// <param name="_aabb1"></param>
/// <param name="_aabb2"></param>
private void AABB_AABB(ABBoxCollider _aabb1, ABBoxCollider _aabb2)
{
_aabb1.ComputeAABB();
_aabb2.ComputeAABB();
if (_aabb1.Min.y > _aabb2.Max.y &&
_aabb1.Max.y < _aabb2.Min.y &&
_aabb1.Min.x < _aabb2.Max.x &&
_aabb1.Max.x > _aabb2.Min.x)
{
// Collision occured between colliders.
ContactDetected = true;
// Difference between the 2 colliders.
var difference = _aabb1.Position - _aabb2.Position;
var xPenetration = _aabb1.Size.x / 2 + _aabb2.Size.x / 2 - Mathf.Abs(difference.x);
if (xPenetration > 0.0f)
{
var yPenetration = _aabb1.Size.y / 2 + _aabb2.Size.y / 2 - Mathf.Abs(difference.y);
if (yPenetration > 0.0f)
{
if (xPenetration < yPenetration)
{
Normal = difference.x < 0 ? Vector2.right : Vector2.left;
Penetration = xPenetration;
}
else
{
Normal = difference.y <= 0 ? Vector2.up : Vector2.down;
Penetration = yPenetration;
}
}
}
}
}
