/// <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;
}
public static Box2D CreateFromCenterSize(float centerX, float centerY, float sizeX, float sizeY)
{
var rectangle = new Box2D(0, 0, sizeX, sizeY);
rectangle.CenterX = centerX;
rectangle.CenterY = centerY;
return(rectangle);
}
public static void TransformCenter(this Box2D rectangle, Matrix3x2 M)
{
Vector2 center = new Vector2(rectangle.CenterX, rectangle.CenterY);
var newCenter = Vector2.Transform(center, M);
rectangle.CenterX = newCenter.X;
rectangle.CenterY = newCenter.Y;
}
public static bool PushYRangeInside(this Box2D rectangleA, Box2D rectangleB)
{
if (rectangleA.SizeY > rectangleB.SizeY)
{
return(false);
}
if (rectangleA.Y < rectangleB.Y)
{
rectangleA.Y = rectangleB.Y;
}
if (rectangleA.MaxY > rectangleB.MaxY)
{
rectangleA.Y = rectangleB.MaxY - rectangleA.SizeY;
}
return(true);
}
public static bool PushXRangeInside(this Box2D rectangleA, Box2D rectangleB)
{
if (rectangleA.SizeX > rectangleB.SizeX)
{
return(false);
}
if (rectangleA.X < rectangleB.X)
{
rectangleA.X = rectangleB.X;
}
if (rectangleA.MaxX > rectangleB.MaxX)
{
rectangleA.X = rectangleB.MaxX - rectangleA.SizeX;
}
return(true);
}
/// <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);
}
public static Box2D CreateFromMinMax(float minX, float minY, float maxX, float maxY)
{
var rectangle = new Box2D(minX, minY, maxX - minX, maxY - minY);
return(rectangle);
}
public static Circle CreateFromBox(Box2D box)
{
var circle = new Circle(box.CenterX, box.CenterY, 0.5f * Math.Min(box.SizeX, box.SizeY));
return(circle);
}