private static bool AABBvsAABBOverlap(GameObject item1, GameObject item2, ref Collision collision)
{
float eps = 1e-3f;
BoxAABB rect1 = item1.AABB;
BoxAABB rect2 = item2.AABB;
if (rect1.max.X <= rect2.min.X || rect1.min.X >= rect2.max.X ||
rect1.max.Y <= rect2.min.Y || rect1.min.Y >= rect2.max.Y)
{
return(false);
}
bool biasX = item1.transform.position.X < item2.transform.position.X;
bool biasY = item1.transform.position.Y < item2.transform.position.Y;
float penX = biasX ? (rect1.max.X - rect2.min.X) : (rect2.max.X - rect1.min.X);
float penY = biasY ? (rect1.max.Y - rect2.min.Y) : (rect2.max.Y - rect1.min.Y);
float diff = penX - penY;
collision.penetration = new Vector2(penX, penY);
if (diff > eps)
{
collision.normal = new Vector2(0, biasY ? 1 : -1);
return(true);
}
if (diff < -eps)
{
collision.normal = new Vector2(biasX ? 1 : -1, 0);
return(true);
}
collision.normal = new Vector2(biasX ? 1 : -1, biasY ? 1 : -1);
return(true);
}
private static bool AABBvsCircleOverlap(GameObject item1, GameObject item2, ref Collision collision)
{
float eps = 1e-3f;
BoxAABB rect = item1.AABB;
TransformBase rectTr = item1.transform;
TransformBase circle = item2.transform;
if (rectTr.position == circle.position)
{
return(false);
}
float radius = Math.Max(circle.size.X, circle.size.Y) / 2f;
Vector2 closest = Vector2.Clamp(circle.position, rect.min, rect.max);
if (closest == circle.position)
{
closest = circle.position.MoveTowards(rectTr.position, eps);
}
Vector2 normal = circle.position - closest;
if (radius * radius <= normal.LengthSquared())
{
return(false);
}
float normalLen = normal.Length();
float pen = radius - normalLen;
collision.penetration = new Vector2(pen);
collision.normal = normal / normalLen;
return(true);
}