public static Matrix3 Abs(Matrix3 m3)
{
Matrix3 absMatrix = new Matrix3(0);
for (int r = 0; r < 3; r++)
{
for (int c = 0; c < 3; c++)
{
absMatrix[r, c] = Math.Abs(m3[r, c]);
}
}
return absMatrix;
}
public Matrix3(Matrix3 m)
{
this.Elements = new float[3, 3];
this.Elements[0, 0] = m[0, 0];
this.Elements[0, 1] = m[0, 1];
this.Elements[0, 2] = m[0, 2];
this.Elements[1, 0] = m[1, 0];
this.Elements[1, 1] = m[1, 1];
this.Elements[1, 2] = m[1, 2];
this.Elements[2, 0] = m[2, 0];
this.Elements[2, 1] = m[2, 1];
this.Elements[2, 2] = m[2, 2];
}
//======================================================================
public bool Intersects(OrientedBoundingBox other)
{
// Matrix to transform other OBB into my reference to allow me to be treated as an AABB
Matrix toMe = other.Transforms * Matrix.Invert(_transforms);
Vector3 centerOther = Utility.Multiply(other.Center, toMe);
Vector3 extentsOther = other.Extents;
Vector3 separation = centerOther - _center;
Matrix3 rotations = new Matrix3(toMe);
Matrix3 absRotations = Utility.Abs(rotations);
float r, r0, r1, r01;
//--- Test case 1 - X axis
r = Math.Abs(separation.X);
r1 = Vector3.Dot(extentsOther, absRotations.Column(0));
r01 = _extents.X + r1;
if (r > r01) return false;
//--- Test case 1 - Y axis
r = Math.Abs(separation.Y);
r1 = Vector3.Dot(extentsOther, absRotations.Column(1));
r01 = _extents.Y + r1;
if (r > r01) return false;
//--- Test case 1 - Z axis
r = Math.Abs(separation.Z);
r1 = Vector3.Dot(extentsOther, absRotations.Column(2));
r01 = _extents.Z + r1;
if (r > r01) return false;
//--- Test case 2 - X axis
r = Math.Abs(Vector3.Dot(rotations.Row(0), separation));
r0 = Vector3.Dot(_extents, absRotations.Row(0));
r01 = r0 + extentsOther.X;
if (r > r01) return false;
//--- Test case 2 - Y axis
r = Math.Abs(Vector3.Dot(rotations.Row(1), separation));
r0 = Vector3.Dot(_extents, absRotations.Row(1));
r01 = r0 + extentsOther.Y;
if (r > r01) return false;
//--- Test case 2 - Z axis
r = Math.Abs(Vector3.Dot(rotations.Row(2), separation));
r0 = Vector3.Dot(_extents, absRotations.Row(2));
r01 = r0 + extentsOther.Z;
if (r > r01) return false;
//--- Test case 3 # 1
r = Math.Abs(separation.Z * rotations[0, 1] - separation.Y * rotations[0, 2]);
r0 = _extents.Y * absRotations[0, 2] + _extents.Z * absRotations[0, 1];
r1 = extentsOther.Y * absRotations[2, 0] + extentsOther.Z * absRotations[1, 0];
r01 = r0 + r1;
if (r > r01) return false;
//--- Test case 3 # 2
r = Math.Abs(separation.Z * rotations[1, 1] - separation.Y * rotations[1, 2]);
r0 = _extents.Y * absRotations[1, 2] + _extents.Z * absRotations[1, 1];
r1 = extentsOther.X * absRotations[2, 0] + extentsOther.Z * absRotations[0, 0];
r01 = r0 + r1;
if (r > r01) return false;
//--- Test case 3 # 3
r = Math.Abs(separation.Z * rotations[2, 1] - separation.Y * rotations[2, 2]);
r0 = _extents.Y * absRotations[2, 2] + _extents.Z * absRotations[2, 1];
r1 = extentsOther.X * absRotations[1, 0] + extentsOther.Y * absRotations[0, 0];
r01 = r0 + r1;
if (r > r01) return false;
//--- Test case 3 # 4
r = Math.Abs(separation.X * rotations[0, 2] - separation.Z * rotations[0, 0]);
r0 = _extents.X * absRotations[0, 2] + _extents.Z * absRotations[0, 0];
r1 = extentsOther.Y * absRotations[2, 1] + extentsOther.Z * absRotations[1, 1];
r01 = r0 + r1;
if (r > r01) return false;
//--- Test case 3 # 5
r = Math.Abs(separation.X * rotations[1, 2] - separation.Z * rotations[1, 0]);
r0 = _extents.X * absRotations[1, 2] + _extents.Z * absRotations[1, 0];
r1 = extentsOther.X * absRotations[2, 1] + extentsOther.Z * absRotations[0, 1];
r01 = r0 + r1;
if (r > r01) return false;
//--- Test case 3 # 6
r = Math.Abs(separation.X * rotations[2, 2] - separation.Z * rotations[2, 0]);
r0 = _extents.X * absRotations[2, 2] + _extents.Z * absRotations[2, 0];
r1 = extentsOther.X * absRotations[1, 1] + extentsOther.Y * absRotations[0, 1];
r01 = r0 + r1;
if (r > r01) return false;
//--- Test case 3 # 7
r = Math.Abs(separation.Y * rotations[0, 0] - separation.X * rotations[0, 1]);
r0 = _extents.X * absRotations[0, 1] + _extents.Y * absRotations[0, 0];
r1 = extentsOther.Y * absRotations[2, 2] + extentsOther.Z * absRotations[1, 2];
r01 = r0 + r1;
if (r > r01) return false;
//--- Test case 3 # 8
r = Math.Abs(separation.Y * rotations[1, 0] - separation.X * rotations[1, 1]);
r0 = _extents.X * absRotations[1, 1] + _extents.Y * absRotations[1, 0];
r1 = extentsOther.X * absRotations[2, 2] + extentsOther.Z * absRotations[0, 2];
r01 = r0 + r1;
if (r > r01) return false;
//--- Test case 3 # 9
r = Math.Abs(separation.Y * rotations[2, 0] - separation.X * rotations[2, 1]);
r0 = _extents.X * absRotations[2, 1] + _extents.Y * absRotations[2, 0];
r1 = extentsOther.X * absRotations[1, 2] + extentsOther.Y * absRotations[0, 2];
r01 = r0 + r1;
if (r > r01) return false;
return true; // No separating axis, then we have intersection
}