static Vector3 RandomPointOutsideShape <T>(IShapeOps <T> h, T obj, Random random)
{
Vector3 p1 = h.RandomInteriorPoint(random);
Vector3 p2 = h.RandomInteriorPoint(random);
for (; ;)
{
// move p2 on a line away from p1 until it's outside
p2 = p1 + (p2 - p1) * 1.1f;
if (!h.ContainsPoint(p2))
{
return(p2);
}
}
}
/// <summary>
/// Test containment and intersection between randomly created shapes of type T1 and T2.
/// </summary>
void TestRandomObjects <T1, T2>(Random random, IShapeOps <T1> h1, IShapeOps <T2> h2, Func <T1, T2, ContainmentType> contains, Func <T1, T2, bool> intersects)
{
// Create a random shape of each type
h1.CreateRandomShape(random, (float)Math.Exp(random.NextDouble() * 4 - 2));
h2.CreateRandomShape(random, (float)Math.Exp(random.NextDouble() * 4 - 2));
// First ensure that the shapes are intersecting (or one is inside the other), by picking a point within each
// and translating so they coincide.
Vector3 p1 = h1.RandomInteriorPoint(random);
Vector3 p2 = h2.RandomInteriorPoint(random);
h2.Translate(p1 - p2);
Check("Contains", h1, h2, contains, c => c != ContainmentType.Disjoint);
Check("Intersects", h1, h2, intersects);
// Next ensure that shape2 is intersecting (not contained or disjoint), by picking another point
// in shape2, and scaling around p1 until the new point is outside of shape1.
p2 = h2.RandomInteriorPoint(random);
while (h1.ContainsPoint(p2))
{
p2 = p1 + (p2 - p1) * 1.1f;
h2.Translate(-p1);
h2.Scale(1.1f);
h2.Translate(p1);
}
Check("surface Intersects", h1, h2, contains, c => c == ContainmentType.Intersects);
Check("Intersects", h1, h2, intersects);
// Ensure that shape2 is fully contained within shape1 by scaling it down
// around a point in shape1, until its hull is inside shape1
for (; ;)
{
Vector3[] hull = h2.GetHull();
bool allInside = true;
foreach (Vector3 point in hull)
{
if (!h1.ContainsPoint(point))
{
allInside = false;
break;
}
}
if (allInside)
{
break;
}
p1 = h1.RandomInteriorPoint(random);
h2.Translate(-p1);
h2.Scale(0.9f);
h2.Translate(p1);
}
// Ensure that shape2 is fully disjoint from shape1 by picking a random plane and
// translating the shapes to opposite sides of it
Plane plane;
plane.Normal = Vector3.Normalize(random.PointInSphere());
plane.D = (float)(random.NextDouble() * 2 - 1) * 100;
h1.Translate((-h1.MinimumDistanceFromPlane(plane) + .001f) * plane.Normal);
plane.D = -plane.D;
plane.Normal = -plane.Normal;
h2.Translate((-h2.MinimumDistanceFromPlane(plane) + .001f) * plane.Normal);
Check("Disjoint", h1, h2, contains, c => c == ContainmentType.Disjoint);
Check("!Intersects", h1, h2, intersects, r => !r);
}