/// <summary>
/// If an intersection with the frame occurs do the minimal translation to undo the overlap
/// </summary>
/// <param name="rectangleB">The AABR to check for intersect</param>
public static void UndoOverlap(this Box2D rectangleA, Box2D rectangleB)
{
if (!rectangleA.Intersects(rectangleB))
{
return;
}
Vector2[] directions = new Vector2[]
{
new Vector2(rectangleB.MaxX - rectangleA.X, 0), // push distance A in positive X-direction
new Vector2(rectangleB.X - rectangleA.MaxX, 0), // push distance A in negative X-direction
new Vector2(0, rectangleB.MaxY - rectangleA.Y), // push distance A in positive Y-direction
new Vector2(0, rectangleB.Y - rectangleA.MaxY) // push distance A in negative Y-direction
};
float[] pushDistSqrd = new float[4];
for (int i = 0; i < 4; ++i)
{
pushDistSqrd[i] = directions[i].LengthSquared();
}
//find minimal positive overlap amount
int minId = 0;
for (int i = 1; i < 4; ++i)
{
minId = pushDistSqrd[i] < pushDistSqrd[minId] ? i : minId;
}
rectangleA.X += directions[minId].X;
rectangleA.Y += directions[minId].Y;
}
/// <summary>
/// Calculates the AABR in the overlap
/// Returns null if no intersection
/// </summary>
/// <param name="rectangleB"></param>
/// <returns>AABR in the overlap</returns>
public static Box2D Overlap(this Box2D rectangleA, Box2D rectangleB)
{
Box2D overlap = null;
if (rectangleA.Intersects(rectangleB))
{
overlap = new Box2D(0.0f, 0.0f, 0.0f, 0.0f);
overlap.X = (rectangleA.X < rectangleB.X) ? rectangleB.X : rectangleA.X;
overlap.Y = (rectangleA.Y < rectangleB.Y) ? rectangleB.Y : rectangleA.Y;
overlap.SizeX = (rectangleA.MaxX < rectangleB.MaxX) ? rectangleA.MaxX - overlap.X : rectangleB.MaxX - overlap.X;
overlap.SizeY = (rectangleA.MaxY < rectangleB.MaxY) ? rectangleA.MaxY - overlap.Y : rectangleB.MaxY - overlap.Y;
}
return(overlap);
}