internal static void Draw(XNACS1Primitive p, XNACS1LibDrawHelper dh)
{
OBB2D a = new OBB2D(p);
dh.DrawLineSegments(a.m_Corner[0], a.m_Corner[1]);
dh.DrawLineSegments(a.m_Corner[1], a.m_Corner[2]);
dh.DrawLineSegments(a.m_Corner[2], a.m_Corner[3]);
dh.DrawLineSegments(a.m_Corner[3], a.m_Corner[0]);
}
internal static void Draw(XNACS1Primitive p, XNACS1LibDrawHelper dh)
{
OBB2D a = new OBB2D(p);
dh.DrawLineSegments(a.m_Corner[0], a.m_Corner[1]);
dh.DrawLineSegments(a.m_Corner[1], a.m_Corner[2]);
dh.DrawLineSegments(a.m_Corner[2], a.m_Corner[3]);
dh.DrawLineSegments(a.m_Corner[3], a.m_Corner[0]);
}
internal static bool OBB2DIntersect(XNACS1Primitive a, XNACS1Primitive b, Vector2 pos)
{
OBB2D aOBB = new OBB2D(a);
OBB2D bOBB = new OBB2D(b);
bool touched = aOBB.overlaps1Way(bOBB) && bOBB.overlaps1Way(aOBB);
if (touched)
{
pos = a.Center + b.Center;
pos /= 2.0f;
}
return touched;
}
internal static bool OBB2DIntersect(XNACS1Primitive a, XNACS1Primitive b, out Vector2 pos)
{
pos = Vector2.Zero;
OBB2D aOBB = new OBB2D(a);
OBB2D bOBB = new OBB2D(b);
bool touched = aOBB.overlaps1Way(bOBB) && bOBB.overlaps1Way(aOBB);
if (touched)
{
pos = a.Center + b.Center;
pos /= 2.0f;
}
return(touched);
}
/// <summary>
/// Determines if this primitive collides with the otherPrimitive. If true, pos is the colliding position.
/// </summary>
/// <param name="otherPrimitive">the other primitive.</param>
/// <param name="pos">If two primitives collide, this is the "average" of all the possible colliding positions.</param>
/// <returns>True: if the two primitives has collided. Pos is the approximated colliding position.
/// False: if the two primitives do not collide, (Pos is undefined in this case).
/// </returns>
public bool Collided(XNACS1Primitive otherPrimitive, out Vector2 pos)
{
if ((m_Type == PrimitiveType.PrimitiveCircle) &&
(otherPrimitive.m_Type == PrimitiveType.PrimitiveCircle))
{
return(CircleCircle(m_Center, SizeX * 0.5f, otherPrimitive.Center, otherPrimitive.SizeX * 0.5f, out pos));
}
else
{
if ((m_Rotate == 0.0f) && (otherPrimitive.m_Rotate == 0.0f))
{
return(RecRec(MinBound, MaxBound, otherPrimitive.MinBound, otherPrimitive.MaxBound, out pos));
}
else
{
return(OBB2D.OBB2DIntersect(this, otherPrimitive, out pos));
}
}
}
private double[] m_Origin; // origin[a] = corner[0].dot(axis[a]);
/** Returns true if other overlaps one dimension of this. */
private bool overlaps1Way(OBB2D other)
{
for (int a = 0; a < 2; ++a)
{
double t = Vector2.Dot(m_Axis[a], other.m_Corner[0]);
// Find the extent of box 2 on axis a
double tMin = t;
double tMax = t;
for (int c = 1; c < 4; ++c)
{
t = Vector2.Dot(m_Axis[a], other.m_Corner[c]);
if (t < tMin)
{
tMin = t;
}
else if (t > tMax)
{
tMax = t;
}
}
// We have to subtract off the origin
// See if [tMin, tMax] intersects [0, 1]
if ((tMin > 1.0 + m_Origin[a]) || (tMax < m_Origin[a]))
{
// There was no intersection along this dimension;
// the boxes cannot possibly overlap.
return(false);
}
}
// There was no dimension along which there is no intersection.
// Therefore the boxes overlap.
return(true);
}
/** Returns true if other overlaps one dimension of this. */
private bool overlaps1Way(OBB2D other)
{
for (int a = 0; a < 2; ++a)
{
double t = Vector2.Dot(m_Axis[a], other.m_Corner[0]);
// Find the extent of box 2 on axis a
double tMin = t;
double tMax = t;
for (int c = 1; c < 4; ++c)
{
t = Vector2.Dot(m_Axis[a], other.m_Corner[c]);
if (t < tMin)
{
tMin = t;
}
else if (t > tMax)
{
tMax = t;
}
}
// We have to subtract off the origin
// See if [tMin, tMax] intersects [0, 1]
if ((tMin > 1.0 + m_Origin[a]) || (tMax < m_Origin[a]))
{
// There was no intersection along this dimension;
// the boxes cannot possibly overlap.
return false;
}
}
// There was no dimension along which there is no intersection.
// Therefore the boxes overlap.
return true;
}
