public Scene(IPrimitive accelerator, List<ILight> lights, IVolumeRegion volumeRegion)
{
Lights = lights;
Aggregate = accelerator;
VolumeRegion = volumeRegion;
Bound = Aggregate.WorldBound;
if (VolumeRegion != null)
Bound = BoundingBox.Union (Bound, VolumeRegion.WorldBound);
}
public static BoundingBox Union(BoundingBox b, Point p)
{
BoundingBox ret = new BoundingBox (b);
ret.pMin.x = Math.Min (b.pMin.x, p.x);
ret.pMin.y = Math.Min (b.pMin.y, p.y);
ret.pMin.z = Math.Min (b.pMin.z, p.z);
ret.pMax.x = Math.Max (b.pMax.x, p.x);
ret.pMax.y = Math.Max (b.pMax.y, p.y);
ret.pMax.z = Math.Max (b.pMax.z, p.z);
return ret;
}
public Grid(List<IPrimitive> primitives, bool refineImmediately)
{
if (refineImmediately)
{
foreach (IPrimitive primitive in primitives)
{
primitive.FullyRefine (ref Primitives);
}
}
else
Primitives = primitives;
foreach (IPrimitive primitive in Primitives)
Bounds = BoundingBox.Union (Bounds, primitive.WorldBound);
Vector delta = Bounds.pMax - Bounds.pMin;
int maxAxis = Bounds.MaximumExtent;
double invMaxWidth = 1.0 / delta[maxAxis];
double cubeRoot = 3.0 * Math.Pow (Primitives.Count, 1.0 / 3.0);
double voxelsPerUnitDistance = cubeRoot * invMaxWidth;
for (int axis = 0; axis < 3; ++axis)
{
nVoxels[axis] = Util.RoundToInt (delta[axis] * voxelsPerUnitDistance);
nVoxels[axis] = Util.Clamp (nVoxels[axis], 1, 64);
}
for (int axis = 0; axis < 3; ++axis)
{
Width[axis] = delta[axis] / nVoxels[axis];
InvWidth[axis] = (Width[axis] == 0.0) ? 0.0 : 1.0 / Width[axis];
}
int nv = nVoxels[0] * nVoxels[1] * nVoxels[2];
Voxels = new Voxel[nv];
foreach (IPrimitive primitive in Primitives)
{
BoundingBox pb = primitive.WorldBound;
int[] vmin = new int[3];
int[] vmax = new int[3];
for (int axis = 0; axis < 3; ++axis)
{
vmin[axis] = PositionToVoxel (pb.pMin, axis);
vmax[axis] = PositionToVoxel (pb.pMax, axis);
}
for (int z = vmin[2]; z <= vmax[2]; ++z)
{
for (int y = vmin[1]; y <= vmax[1]; ++y)
{
for (int x = vmin[0]; x <= vmax[0]; ++x)
{
int o = Offset (x, y, z);
if (Voxels[o] == null)
{
Voxels[o] = new Voxel (primitive);
}
else
{
Voxels[o].AddPrimitive (primitive);
}
}
}
}
}
}
/// <summary>
/// Builds the Kd-Tree
/// </summary>
/// <param name="nodeNum">
/// The current node index
/// </param>
/// <param name="nodeBounds">
/// The node's bounding box
/// </param>
/// <param name="allPrimBounds">
/// The primitive's bounding boxes
/// </param>
/// <param name="primNums">
/// Array of primitive indices
/// </param>
/// <param name="numberOfPrimitives">
/// Number of primitives to build from
/// </param>
/// <param name="depth">
/// The current recursion depth
/// </param>
/// <param name="edges">
/// Array of edges
/// </param>
/// <param name="prims0">
///
/// </param>
/// <param name="prims1">
///
/// </param>
/// <param name="badRefines">
/// Amount of bad refines
/// </param>
public void BuildTree(int nodeNum, BoundingBox nodeBounds, List<BoundingBox> allPrimBounds,
int[] primNums, int numberOfPrimitives, int depth, List<BoundEdge>[] edges,
int[] prims0, int[] prims1, int primIndex,
int badRefines)
{
if (_nextFreeNode == _numberOfAllocatedNodes)
{
int nAlloc = Math.Max (2 * _numberOfAllocatedNodes, 512);
KdAcceleratorNode[] n = new KdAcceleratorNode[nAlloc];
if (_numberOfAllocatedNodes > 0)
{
_nodes.CopyTo (n, 0);
}
_nodes = n;
_numberOfAllocatedNodes = nAlloc;
}
++_nextFreeNode;
// Initialize leaf nodes if termination criteria is met
if (numberOfPrimitives <= _maxPrimitives || depth == 0)
{
_nodes[nodeNum].InitLeaf (primNums, numberOfPrimitives);
return;
}
// Initialize interior node and continue recursion.
// Choose split axis position for interior node
int bestAxis = -1, bestOffset = -1;
double bestCost = double.PositiveInfinity;
double oldCost = _isectCost * numberOfPrimitives;
double totalSA = nodeBounds.SurfaceArea;
double invTotalSA = 1.0 / totalSA;
Vector d = nodeBounds.pMax - nodeBounds.pMin;
int axis = nodeBounds.MaximumExtent;
int retries = 0;
while (true)
{
// Initialize edges for axis
for (int i = 0; i < numberOfPrimitives; ++i)
{
int pn = (int)primNums[i];
BoundingBox box = allPrimBounds[pn];
edges[axis][2 * i] = new BoundEdge (box.pMin[axis], pn, true);
edges[axis][2 * i + 1] = new BoundEdge (box.pMax[axis], pn, false);
}
edges[axis].Sort (0, 2 * numberOfPrimitives, comparer);
// Compute cost of all splits for axis to find best
int nBelow = 0, nAbove = numberOfPrimitives;
for (int i = 0; i < 2 * numberOfPrimitives; ++i)
{
if (edges[axis][i].Type == BoundEdge.EdgeType.End)
--nAbove;
double edget = edges[axis][i].t;
if (edget > nodeBounds.pMin[axis] && edget < nodeBounds.pMax[axis])
{
int otherAxis0 = (axis + 1) % 3, otherAxis1 = (axis + 2) % 3;
double belowSA = 2 * (d[otherAxis0] * d[otherAxis1] + (edget - nodeBounds.pMin[axis]) * (d[otherAxis0] + d[otherAxis1]));
double aboveSA = 2 * (d[otherAxis0] * d[otherAxis1] + (nodeBounds.pMax[axis] - edget) * (d[otherAxis0] + d[otherAxis1]));
double pBelow = belowSA * invTotalSA;
double pAbove = aboveSA * invTotalSA;
double eb = (nAbove == 0 || nBelow == 0) ? _emptyBonus : 0.0;
double cost = _traversalCost + _isectCost * (1.0 - eb) * (pBelow * nBelow + pAbove * nAbove);
// Update best split if this is the lowest so far
if (cost < bestCost)
{
bestCost = cost;
bestAxis = axis;
bestOffset = i;
}
}
if (edges[axis][i].Type == BoundEdge.EdgeType.Start)
++nBelow;
}
// Create leaf if no good splits were found
if (bestAxis == -1 && retries < 2)
{
++retries;
axis = (axis + 1) % 3;
continue;
}
break;
}
if (bestCost > oldCost)
++badRefines;
if ((bestCost > 4.0 * oldCost && numberOfPrimitives < 16) || bestAxis == -1 || badRefines == 3)
{
_nodes[nodeNum].InitLeaf (primNums, numberOfPrimitives);
return;
}
// Classify primitives with respect to split
int n0 = 0, n1 = 0;
for (int i = 0; i < bestOffset; ++i)
if (edges[bestAxis][i].Type == BoundEdge.EdgeType.Start)
prims0[n0++] = edges[bestAxis][i].PrimitiveNumber;
for (int i = bestOffset + 1; i < 2 * numberOfPrimitives; ++i)
if (edges[bestAxis][i].Type == BoundEdge.EdgeType.End)
prims1[primIndex + n1++] = edges[bestAxis][i].PrimitiveNumber;
// Recursively initialize child nodes
double tsplit = edges[bestAxis][bestOffset].t;
BoundingBox bounds0 = new BoundingBox (nodeBounds), bounds1 = new BoundingBox(nodeBounds);
bounds0.pMax[bestAxis] = bounds1.pMin[bestAxis] = tsplit;
BuildTree (nodeNum + 1, bounds0, allPrimBounds, prims0, n0, depth - 1, edges, prims0, prims1, numberOfPrimitives + primIndex, badRefines);
int aboveChild = _nextFreeNode;
_nodes[nodeNum].InitInterior (bestAxis, aboveChild, tsplit);
BuildTree (aboveChild, bounds1, allPrimBounds, prims1, n1, depth - 1, edges, prims0, prims1, numberOfPrimitives + primIndex, badRefines);
}
/// <summary>
/// Creates a new KdTree
/// </summary>
/// <param name="p">
/// List of primitives to build the kd-Tree from
/// </param>
/// <param name="isectCost">
/// Cost for an intersection
/// </param>
/// <param name="traversalCost">
/// Cost for traversing along edges
/// </param>
/// <param name="emptyBonus">
/// Bonus for empty leafs
/// </param>
/// <param name="maxPrimitives">
/// Maximum amount of primitives per leaf
/// </param>
/// <param name="maxDepth">
/// Maximum recursion depth
/// </param>
public KdTree(List<IPrimitive> p, int isectCost, int traversalCost, double emptyBonus, int maxPrimitives, int maxDepth)
{
_isectCost = isectCost;
_traversalCost = traversalCost;
_emptyBonus = emptyBonus;
_maxPrimitives = maxPrimitives;
_maxDepth = maxDepth;
Console.WriteLine (" - Refining {0} primitives...", p.Count);
foreach (IPrimitive primitive in p)
primitive.FullyRefine (ref _primitives);
Console.WriteLine (" - Refined into {0} primitives", _primitives.Count);
// Build kd-Tree
_nextFreeNode = _numberOfAllocatedNodes = 0;
if (_maxDepth <= 0)
_maxDepth = Util.RoundToInt (8 + 1.3 * Util.Log2Int ((double)_primitives.Count));
// Compute bounds for kd-Tree generation
List<BoundingBox> primitiveBounds = new List<BoundingBox> ();
primitiveBounds.Capacity = _primitives.Count;
foreach (IPrimitive primitive in _primitives)
{
BoundingBox b = primitive.WorldBound;
_bounds = BoundingBox.Union (_bounds, b);
primitiveBounds.Add (b);
}
Console.WriteLine (" - KdTree Volume: {0}", _bounds.Volume);
// Allocate working memory for kd-Tree construction
List<BoundEdge>[] edges = new List<BoundEdge>[3];
edges[0] = new List<BoundEdge> ();
edges[1] = new List<BoundEdge> ();
edges[2] = new List<BoundEdge> ();
for (int i = 0; i < 3; ++i)
{
edges[i].Capacity = 2 * _primitives.Count;
for (int j = 0; j < 2 * _primitives.Count; ++j)
edges[i].Add (null);
}
int[] prims0 = new int[_primitives.Count];
int[] prims1 = new int[(_maxDepth + 1) * _primitives.Count];
// Initialize primNums for kd-Tree construction
int[] primNums = new int[_primitives.Count];
for (int i = 0; i < _primitives.Count; ++i)
primNums[i] = i;
// Start recursive construction of kd-Tree
Console.WriteLine (" - Building KdTree for {0} primitives...", _primitives.Count);
BuildTree (0, _bounds, primitiveBounds, primNums, _primitives.Count, _maxDepth, edges, prims0, prims1, 0, 0);
Console.WriteLine (" - Created KdTree with {0} nodes and {1} leafs.", NumberOfTotalNodes, NumberOfTotalLeafs);
}
public static BoundingBox Union(BoundingBox b, BoundingBox b2)
{
BoundingBox ret = new BoundingBox (b);
ret.pMin.x = Math.Min (b.pMin.x, b2.pMin.x);
ret.pMin.y = Math.Min (b.pMin.y, b2.pMin.y);
ret.pMin.z = Math.Min (b.pMin.z, b2.pMin.z);
ret.pMax.x = Math.Max (b.pMax.x, b2.pMax.x);
ret.pMax.y = Math.Max (b.pMax.y, b2.pMax.y);
ret.pMax.z = Math.Max (b.pMax.z, b2.pMax.z);
return ret;
}
public BoundingBox(BoundingBox b)
{
pMin = new Point (b.pMin);
pMax = new Point (b.pMax);
}
public bool Overlaps(BoundingBox b)
{
bool x = (pMax.x >= b.pMin.x) && (pMin.x <= b.pMax.x);
bool y = (pMax.y >= b.pMin.y) && (pMin.y <= b.pMax.y);
bool z = (pMax.z >= b.pMin.z) && (pMin.z <= b.pMax.z);
return (x && y && z);
}
