public DistanceGrid(Shape shape, Scalar spacing)
{
if (shape == null) { throw new ArgumentNullException("shape"); }
if (spacing <= 0) { throw new ArgumentOutOfRangeException("spacing"); }
//prepare the shape.
Matrix2D old = shape.Matrix;
Matrix2D ident = Matrix2D.Identity;
shape.ApplyMatrix(ref ident);
shape.CalcBoundingBox2D();
this.box = shape.BoundingBox2D;
this.gridSpacing = spacing;
this.gridSpacingInv = 1 / spacing;
int xSize = (int)Math.Ceiling((box.Upper.X - box.Lower.X) * gridSpacingInv) + 2;
int ySize = (int)Math.Ceiling((box.Upper.Y - box.Lower.Y) * gridSpacingInv) + 2;
this.nodes = new Scalar[xSize, ySize];
Vector2D vector;
vector.X = box.Lower.X;
for (int x = 0; x < xSize; ++x, vector.X += spacing)
{
vector.Y = box.Lower.Y;
for (int y = 0; y < ySize; ++y, vector.Y += spacing)
{
nodes[x, y] = shape.GetDistance(vector);
}
}
//restore the shape
shape.ApplyMatrix(ref old);
shape.CalcBoundingBox2D();
}
public override void CalcBoundingBox2D()
{
boundingBox = new BoundingBox2D(
position.X + radius,
position.Y + radius,
position.X - radius,
position.Y - radius);
}
static void Collide(List<Contact> contacts, Body entity1, Body entity2, ref BoundingBox2D targetArea)
{
if (!entity1.Shape.CanGetIntersection)
{
return;
}
Vector2D[] vertexes = entity2.Shape.Vertices;
Array.Resize<Vector2D>(ref vertexes, vertexes.Length + 2);
vertexes[vertexes.Length - 2] = Vector2D.Zero;
vertexes[vertexes.Length - 1] = Vector2D.XAxis;
for (int index = 0; index < vertexes.Length; ++index)
{
Vector2D vector = vertexes[index];
if (BoundingBox2D.TestIntersection(ref targetArea, ref vector))
{
IntersectionInfo info;
if (entity1.Shape.TryGetIntersection(vector, out info))
{
Contact contact = new Contact();
contact.normal = info.Normal;
if (Scalar.IsNaN(contact.normal.X) ||
Scalar.IsNaN(contact.normal.Y))
{
continue;
}
contact.distance = info.Distance;
contact.position = vector;
contact.id = index + 1;
if (entity1.ID < entity2.ID)
{
contact.id = -contact.id;
}
else
{
Vector2D.Negate(ref contact.normal, out contact.normal);
}
contacts.Add(contact);
}
}
}
}
public static void FromVectors(ref Vector2D first, ref Vector2D second, out BoundingBox2D result)
{
if (first.X > second.X)
{
result.Upper.X = first.X;
result.Lower.X = second.X;
}
else
{
result.Upper.X = second.X;
result.Lower.X = first.X;
}
if (first.Y > second.Y)
{
result.Upper.Y = first.Y;
result.Lower.Y = second.Y;
}
else
{
result.Upper.Y = second.Y;
result.Lower.Y = first.Y;
}
}
public static bool TestIntersection(ref BoundingBox2D box1, ref BoundingBox2D box2)
{
return !
((box1.Lower.X >= box2.Upper.X) || (box1.Upper.X <= box2.Lower.X) ||
(box2.Lower.Y >= box1.Upper.Y) || (box2.Upper.Y <= box1.Lower.Y));
}
public static bool TestIntersection(ref BoundingBox2D box, ref Vector2D point)
{
return
box.Upper.X >= point.X && box.Lower.X <= point.X &&
box.Upper.Y >= point.Y && box.Lower.Y <= point.Y;
}
public static void FromIntersection(ref BoundingBox2D first, ref BoundingBox2D second, out BoundingBox2D result)
{
result.Upper.X = MathHelper.Min(first.Upper.X, second.Upper.X);
result.Upper.Y = MathHelper.Min(first.Upper.Y, second.Upper.Y);
result.Lower.X = MathHelper.Max(first.Lower.X, second.Lower.X);
result.Lower.Y = MathHelper.Max(first.Lower.Y, second.Lower.Y);
}
/// <summary>
/// Makes a BoundingBox2D that contains the area where the BoundingBox2Ds Intersect.
/// </summary>
/// <param name="first">The First BoundingBox2D.</param>
/// <param name="second">The Second BoundingBox2D.</param>
/// <returns>The BoundingBox2D that can contain the 2 BoundingBox2Ds passed.</returns>
public static BoundingBox2D FromIntersection(BoundingBox2D first, BoundingBox2D second)
{
BoundingBox2D result;
result.Upper.X = MathHelper.Min(first.Upper.X, second.Upper.X);
result.Upper.Y = MathHelper.Min(first.Upper.Y, second.Upper.Y);
result.Lower.X = MathHelper.Max(first.Lower.X, second.Lower.X);
result.Lower.Y = MathHelper.Max(first.Lower.Y, second.Lower.Y);
return result;
}
public static void FromVectors(Vector2D[] vectors, out BoundingBox2D result)
{
if (vectors == null) { throw new ArgumentNullException("vectors"); }
if (vectors.Length == 0) { throw new ArgumentOutOfRangeException("vectors"); }
int length = vectors.Length;
result.Upper = vectors[0];
result.Lower = vectors[0];
for (int pos = 1; pos < length; ++pos)
{
Vector2D current = vectors[pos];
if (current.X > result.Upper.X)
{
result.Upper.X = current.X;
}
else if (current.X < result.Lower.X)
{
result.Lower.X = current.X;
}
if (current.Y > result.Upper.Y)
{
result.Upper.Y = current.Y;
}
else if (vectors[pos].Y < result.Lower.Y)
{
result.Lower.Y = current.Y;
}
}
}
