// Returns true if the two AABBs intersect, false otherwise
public static bool CheckIntersection(AABB first, AABB second)
{
for (int dim = 0; dim < 3; dim++)
if (first.array[dim][1] < second.array[dim][0] || first.array[dim][0] > second.array[dim][1])
return false;
return true;
}
public PartitioningGrid(AABB bounds, int max_subdivisions)
{
this.bounds = bounds;
this.max_subdivisions = max_subdivisions;
items = new List<int>[2];
for(int i = 0; i < 2; i++)
items[i] = new List<int>();
}
// Computes and returns an AABB encompassing the intersection of the two input boxes' volumes
// Don't use this value if CheckIntersection failed!
public static AABB Intersection(AABB first, AABB second)
{
AABB result = new AABB { array = EmptyBoundsArray };
for (int dim = 0; dim < 3; dim++)
{
result.array[dim][0] = Math.Max(first.array[dim][0], second.array[dim][0]);
result.array[dim][1] = Math.Min(first.array[dim][1], second.array[dim][1]);
}
return result;
}
// Returns an AABB expanded from the input AABB as necessary in order to include the specified point
public static AABB ExpandedToFit(AABB input, Vec3 point)
{
AABB result = new AABB { array = EmptyBoundsArray };
double[] point_array = new double[] { point.x, point.y, point.z };
for (int dim = 0; dim < 3; dim++)
{
result.array[dim][0] = Math.Min(input.array[dim][0], point_array[dim]);
result.array[dim][1] = Math.Max(input.array[dim][1], point_array[dim]);
}
return result;
}
// Inserts an item into the category-th list (possibly of children, based on the item's bounding box)
public void InsertItem(int category, int item, AABB box)
{
if(AABB.CheckIntersection(box, bounds))
{
items[category].Add(item);
if (children == null && max_subdivisions > 0)
Subdivide();
if (children != null)
foreach (PartitioningGrid grid in children)
grid.InsertItem(category, item, box);
}
max_encountered_item[category] = Math.Max(max_encountered_item[category], item);
}
// Utility function to figure out how well a subdivision point splits stuff
public int[,,] CheckSubdivision(Vec3 split)
{
int[, ,] results = new int[2, 2, 2];
double[][] array = new double[][]
{
new double[] { bounds.array[0][0], split.x, bounds.array[0][1] },
new double[] { bounds.array[1][0], split.y, bounds.array[1][1] },
new double[] { bounds.array[2][0], split.z, bounds.array[2][1] }
};
for (int i = 0; i < 2; i++)
for (int j = 0; j < 2; j++)
for (int k = 0; k < 2; k++)
{
AABB subregion = new AABB { array = new double[][] { new double[] { array[0][i], array[0][i + 1] }, new double[] { array[1][j], array[1][j + 1] }, new double[] { array[2][k], array[2][k + 1] } } };
foreach (Item item in items)
if (AABB.CheckIntersection(item.aabb, subregion))
results[i, j, k]++;
}
return results;
}
public Octree(AABB bounds)
{
this.bounds = bounds;
items = new List<Item>();
}
// Function defining how to subdivide an Octree
// Return values should generally be the same type as the subtype of Octree
protected virtual Octree Subdivision(AABB aabb)
{
return new Octree(aabb);
}
// Boring constructor
// Just calls BoundsInit with the same arguments you gave the constructor
public ModelIntersectTree(AABB bounds, int max_subdivisions)
{
BoundsInit(bounds, max_subdivisions);
}
protected virtual void BoundsInit(AABB bounds, int max_subdivisions)
{
this.bounds = bounds;
this.max_subdivisions = max_subdivisions;
items = new List<Octree.Item>[2];
for (int i = 0; i < 2; i++)
items[i] = new List<Octree.Item>();
}
