637 lines
25 KiB
C#
637 lines
25 KiB
C#
/*
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* Copyright (C) 2012-2017 CypherCore <http://github.com/CypherCore>
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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using Framework.GameMath;
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using System;
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using System.Collections.Generic;
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using System.IO;
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using System.Linq;
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using System.Runtime.InteropServices;
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namespace Game.Collision
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{
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public class BIH
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{
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public BIH()
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{
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init_empty();
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}
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void init_empty()
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{
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tree.Clear();
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objects.Clear();
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// create space for the first node
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tree.Add(3u << 30); // dummy leaf
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tree.Add(0);
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tree.Add(0);
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}
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public void build<T>(List<T> primitives, uint leafSize = 3, bool printStats = false) where T : IModel
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{
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if (primitives.Count == 0)
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{
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init_empty();
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return;
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}
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buildData dat;
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dat.maxPrims = (int)leafSize;
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dat.numPrims = (uint)primitives.Count;
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dat.indices = new uint[dat.numPrims];
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dat.primBound = new AxisAlignedBox[dat.numPrims];
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bounds = primitives[0].getBounds();
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for (int i = 0; i < dat.numPrims; ++i)
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{
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dat.indices[i] = (uint)i;
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dat.primBound[i] = primitives[i].getBounds();
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bounds.merge(dat.primBound[i]);
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}
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List<uint> tempTree = new List<uint>();
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BuildStats stats = new BuildStats();
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buildHierarchy(tempTree, dat, stats);
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if (printStats)
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stats.printStats();
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for (int i = 0; i < dat.numPrims; ++i)
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objects.Add(dat.indices[i]);
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tree = tempTree;
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}
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public uint primCount() { return (uint)objects.Count; }
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public bool readFromFile(BinaryReader reader)
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{
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var lo = reader.ReadStruct<Vector3>();
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var hi = reader.ReadStruct<Vector3>();
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bounds = new AxisAlignedBox(lo, hi);
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uint treeSize = reader.ReadUInt32();
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tree.Clear();
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for (var i = 0; i < treeSize; i++)
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tree.Add(reader.ReadUInt32());
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var count = reader.ReadUInt32();
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objects.Clear();
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for (var i = 0; i < count; i++)
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objects.Add(reader.ReadUInt32());
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return true;
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}
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public void intersectRay(Ray r, WorkerCallback intersectCallback, ref float maxDist, bool stopAtFirst = false)
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{
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float intervalMin = -1.0f;
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float intervalMax = -1.0f;
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Vector3 org = r.Origin;
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Vector3 dir = r.Direction;
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Vector3 invDir = new Vector3();
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for (int i = 0; i < 3; ++i)
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{
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invDir[i] = 1.0f / dir[i];
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if (MathFunctions.fuzzyNe(dir[i], 0.0f))
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{
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float t1 = (bounds.Lo[i] - org[i]) * invDir[i];
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float t2 = (bounds.Hi[i] - org[i]) * invDir[i];
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if (t1 > t2)
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MathFunctions.Swap<float>(ref t1, ref t2);
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if (t1 > intervalMin)
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intervalMin = t1;
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if (t2 < intervalMax || intervalMax < 0.0f)
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intervalMax = t2;
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// intervalMax can only become smaller for other axis,
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// and intervalMin only larger respectively, so stop early
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if (intervalMax <= 0 || intervalMin >= maxDist)
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return;
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}
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}
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if (intervalMin > intervalMax)
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return;
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intervalMin = Math.Max(intervalMin, 0.0f);
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intervalMax = Math.Min(intervalMax, maxDist);
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uint[] offsetFront = new uint[3];
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uint[] offsetBack = new uint[3];
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uint[] offsetFront3 = new uint[3];
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uint[] offsetBack3 = new uint[3];
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// compute custom offsets from direction sign bit
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for (int i = 0; i < 3; ++i)
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{
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offsetFront[i] = floatToRawIntBits(dir[i]) >> 31;
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offsetBack[i] = offsetFront[i] ^ 1;
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offsetFront3[i] = offsetFront[i] * 3;
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offsetBack3[i] = offsetBack[i] * 3;
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// avoid always adding 1 during the inner loop
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++offsetFront[i];
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++offsetBack[i];
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}
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StackNode[] stack = new StackNode[64];
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int stackPos = 0;
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int node = 0;
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while (true)
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{
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while (true)
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{
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uint tn = tree[node];
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uint axis = (uint)(tn & (3 << 30)) >> 30;
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bool BVH2 = Convert.ToBoolean(tn & (1 << 29));
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int offset = (int)(tn & ~(7 << 29));
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if (!BVH2)
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{
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if (axis < 3)
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{
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// "normal" interior node
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float tf = (intBitsToFloat(tree[(int)(node + offsetFront[axis])]) - org[axis]) * invDir[axis];
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float tb = (intBitsToFloat(tree[(int)(node + offsetBack[axis])]) - org[axis]) * invDir[axis];
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// ray passes between clip zones
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if (tf < intervalMin && tb > intervalMax)
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break;
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int back = (int)(offset + offsetBack3[axis]);
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node = back;
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// ray passes through far node only
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if (tf < intervalMin)
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{
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intervalMin = (tb >= intervalMin) ? tb : intervalMin;
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continue;
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}
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node = offset + (int)offsetFront3[axis]; // front
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// ray passes through near node only
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if (tb > intervalMax)
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{
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intervalMax = (tf <= intervalMax) ? tf : intervalMax;
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continue;
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}
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// ray passes through both nodes
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// push back node
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stack[stackPos].node = (uint)back;
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stack[stackPos].tnear = (tb >= intervalMin) ? tb : intervalMin;
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stack[stackPos].tfar = intervalMax;
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stackPos++;
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// update ray interval for front node
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intervalMax = (tf <= intervalMax) ? tf : intervalMax;
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continue;
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}
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else
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{
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// leaf - test some objects
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int n = (int)tree[node + 1];
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while (n > 0)
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{
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bool hit = intersectCallback.Invoke(r, objects[offset], ref maxDist, stopAtFirst);
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if (stopAtFirst && hit)
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return;
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--n;
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++offset;
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}
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break;
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}
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}
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else
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{
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if (axis > 2)
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return; // should not happen
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float tf = (intBitsToFloat(tree[(int)(node + offsetFront[axis])]) - org[axis]) * invDir[axis];
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float tb = (intBitsToFloat(tree[(int)(node + offsetBack[axis])]) - org[axis]) * invDir[axis];
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node = offset;
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intervalMin = (tf >= intervalMin) ? tf : intervalMin;
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intervalMax = (tb <= intervalMax) ? tb : intervalMax;
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if (intervalMin > intervalMax)
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break;
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continue;
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}
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} // traversal loop
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do
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{
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// stack is empty?
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if (stackPos == 0)
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return;
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// move back up the stack
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stackPos--;
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intervalMin = stack[stackPos].tnear;
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if (maxDist < intervalMin)
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continue;
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node = (int)stack[stackPos].node;
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intervalMax = stack[stackPos].tfar;
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break;
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} while (true);
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}
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}
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public void intersectPoint(Vector3 p, WorkerCallback intersectCallback)
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{
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if (!bounds.contains(p))
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return;
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StackNode[] stack = new StackNode[64];
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int stackPos = 0;
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int node = 0;
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while (true)
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{
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while (true)
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{
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uint tn = tree[node];
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uint axis = (uint)(tn & (3 << 30)) >> 30;
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bool BVH2 = Convert.ToBoolean(tn & (1 << 29));
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int offset = (int)(tn & ~(7 << 29));
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if (!BVH2)
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{
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if (axis < 3)
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{
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// "normal" interior node
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float tl = intBitsToFloat(tree[node + 1]);
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float tr = intBitsToFloat(tree[node + 2]);
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// point is between clip zones
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if (tl < p[(int)axis] && tr > p[axis])
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break;
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int right = offset + 3;
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node = right;
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// point is in right node only
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if (tl < p[(int)axis])
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{
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continue;
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}
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node = offset; // left
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// point is in left node only
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if (tr > p[axis])
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{
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continue;
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}
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// point is in both nodes
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// push back right node
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stack[stackPos].node = (uint)right;
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stackPos++;
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continue;
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}
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else
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{
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// leaf - test some objects
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uint n = tree[node + 1];
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while (n > 0)
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{
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intersectCallback.Invoke(p, objects[offset]); // !!!
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--n;
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++offset;
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}
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break;
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}
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}
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else // BVH2 node (empty space cut off left and right)
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{
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if (axis > 2)
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return; // should not happen
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float tl = intBitsToFloat(tree[node + 1]);
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float tr = intBitsToFloat(tree[node + 2]);
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node = offset;
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if (tl > p[axis] || tr < p[axis])
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break;
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continue;
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}
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} // traversal loop
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// stack is empty?
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if (stackPos == 0)
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return;
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// move back up the stack
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stackPos--;
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node = (int)stack[stackPos].node;
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}
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}
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void buildHierarchy(List<uint> tempTree, buildData dat, BuildStats stats)
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{
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// create space for the first node
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tempTree.Add(3u << 30); // dummy leaf
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tempTree.Add(0);
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tempTree.Add(0);
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// seed bbox
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AABound gridBox = new AABound();
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gridBox.lo = bounds.Lo;
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gridBox.hi = bounds.Hi;
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AABound nodeBox = gridBox;
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// seed subdivide function
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subdivide(0, (int)(dat.numPrims - 1), tempTree, dat, gridBox, nodeBox, 0, 1, stats);
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}
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void subdivide(int left, int right, List<uint> tempTree, buildData dat, AABound gridBox, AABound nodeBox, int nodeIndex, int depth, BuildStats stats)
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{
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if ((right - left + 1) <= dat.maxPrims || depth >= 64)
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{
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// write leaf node
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stats.updateLeaf(depth, right - left + 1);
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createNode(tempTree, nodeIndex, left, right);
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return;
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}
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// calculate extents
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int axis = -1, prevAxis, rightOrig;
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float clipL = float.NaN, clipR = float.NaN, prevClip = float.NaN;
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float split = float.NaN, prevSplit;
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bool wasLeft = true;
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while (true)
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{
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prevAxis = axis;
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prevSplit = split;
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// perform quick consistency checks
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Vector3 d = gridBox.hi - gridBox.lo;
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for (int i = 0; i < 3; i++)
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{
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if (nodeBox.hi[i] < gridBox.lo[i] || nodeBox.lo[i] > gridBox.hi[i])
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Log.outError(LogFilter.Server, "Reached tree area in error - discarding node with: {0} objects", right - left + 1);
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}
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// find longest axis
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axis = (int)d.primaryAxis();
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split = 0.5f * (gridBox.lo[axis] + gridBox.hi[axis]);
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// partition L/R subsets
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clipL = float.NegativeInfinity;
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clipR = float.PositiveInfinity;
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rightOrig = right; // save this for later
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float nodeL = float.PositiveInfinity;
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float nodeR = float.NegativeInfinity;
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for (int i = left; i <= right; )
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{
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int obj = (int)dat.indices[i];
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float minb = dat.primBound[obj].Lo[axis];
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float maxb = dat.primBound[obj].Hi[axis];
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float center = (minb + maxb) * 0.5f;
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if (center <= split)
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{
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// stay left
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i++;
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if (clipL < maxb)
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clipL = maxb;
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}
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else
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{
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// move to the right most
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int t = (int)dat.indices[i];
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dat.indices[i] = dat.indices[right];
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dat.indices[right] = (uint)t;
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right--;
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if (clipR > minb)
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clipR = minb;
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}
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nodeL = Math.Min(nodeL, minb);
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nodeR = Math.Max(nodeR, maxb);
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}
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// check for empty space
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if (nodeL > nodeBox.lo[axis] && nodeR < nodeBox.hi[axis])
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{
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float nodeBoxW = nodeBox.hi[axis] - nodeBox.lo[axis];
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float nodeNewW = nodeR - nodeL;
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// node box is too big compare to space occupied by primitives?
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if (1.3f * nodeNewW < nodeBoxW)
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{
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stats.updateBVH2();
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int nextIndex1 = tempTree.Count();
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// allocate child
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tempTree.Add(0);
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tempTree.Add(0);
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tempTree.Add(0);
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// write bvh2 clip node
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stats.updateInner();
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tempTree[nodeIndex + 0] = (uint)((axis << 30) | (1 << 29) | nextIndex1);
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tempTree[nodeIndex + 1] = floatToRawIntBits(nodeL);
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tempTree[nodeIndex + 2] = floatToRawIntBits(nodeR);
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// update nodebox and recurse
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nodeBox.lo[axis] = nodeL;
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nodeBox.hi[axis] = nodeR;
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subdivide(left, rightOrig, tempTree, dat, gridBox, nodeBox, nextIndex1, depth + 1, stats);
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return;
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}
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}
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// ensure we are making progress in the subdivision
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if (right == rightOrig)
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{
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// all left
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if (prevAxis == axis && MathFunctions.fuzzyEq(prevSplit, split))
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{
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// we are stuck here - create a leaf
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stats.updateLeaf(depth, right - left + 1);
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createNode(tempTree, nodeIndex, left, right);
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return;
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}
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if (clipL <= split)
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{
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// keep looping on left half
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gridBox.hi[axis] = split;
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prevClip = clipL;
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wasLeft = true;
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continue;
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}
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gridBox.hi[axis] = split;
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prevClip = float.NaN;
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}
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else if (left > right)
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{
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// all right
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right = rightOrig;
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if (prevAxis == axis && MathFunctions.fuzzyEq(prevSplit, split))
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{
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// we are stuck here - create a leaf
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stats.updateLeaf(depth, right - left + 1);
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createNode(tempTree, nodeIndex, left, right);
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return;
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}
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if (clipR >= split)
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{
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// keep looping on right half
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gridBox.lo[axis] = split;
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prevClip = clipR;
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wasLeft = false;
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continue;
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}
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gridBox.lo[axis] = split;
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prevClip = float.NaN;
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}
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else
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{
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// we are actually splitting stuff
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if (prevAxis != -1 && !float.IsNaN(prevClip))
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{
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// second time through - lets create the previous split
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// since it produced empty space
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int nextIndex0 = tempTree.Count;
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// allocate child node
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tempTree.Add(0);
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tempTree.Add(0);
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tempTree.Add(0);
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if (wasLeft)
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{
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// create a node with a left child
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// write leaf node
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stats.updateInner();
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tempTree[nodeIndex + 0] = (uint)((prevAxis << 30) | nextIndex0);
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tempTree[nodeIndex + 1] = floatToRawIntBits(prevClip);
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tempTree[nodeIndex + 2] = floatToRawIntBits(float.PositiveInfinity);
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}
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else
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{
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// create a node with a right child
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// write leaf node
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stats.updateInner();
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tempTree[nodeIndex + 0] = (uint)((prevAxis << 30) | (nextIndex0 - 3));
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tempTree[nodeIndex + 1] = floatToRawIntBits(float.NegativeInfinity);
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tempTree[nodeIndex + 2] = floatToRawIntBits(prevClip);
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}
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// count stats for the unused leaf
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depth++;
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stats.updateLeaf(depth, 0);
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// now we keep going as we are, with a new nodeIndex:
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nodeIndex = nextIndex0;
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}
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break;
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}
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}
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// compute index of child nodes
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int nextIndex = tempTree.Count;
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// allocate left node
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int nl = right - left + 1;
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int nr = rightOrig - (right + 1) + 1;
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if (nl > 0)
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{
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tempTree.Add(0);
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tempTree.Add(0);
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tempTree.Add(0);
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}
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else
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nextIndex -= 3;
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// allocate right node
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if (nr > 0)
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{
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tempTree.Add(0);
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tempTree.Add(0);
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tempTree.Add(0);
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}
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// write leaf node
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stats.updateInner();
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tempTree[nodeIndex + 0] = (uint)((axis << 30) | nextIndex);
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tempTree[nodeIndex + 1] = floatToRawIntBits(clipL);
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tempTree[nodeIndex + 2] = floatToRawIntBits(clipR);
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// prepare L/R child boxes
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AABound gridBoxL = gridBox;
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AABound gridBoxR = gridBox;
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AABound nodeBoxL = nodeBox;
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AABound nodeBoxR = nodeBox;
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|
gridBoxL.hi[axis] = gridBoxR.lo[axis] = split;
|
|
nodeBoxL.hi[axis] = clipL;
|
|
nodeBoxR.lo[axis] = clipR;
|
|
// recurse
|
|
if (nl > 0)
|
|
subdivide(left, right, tempTree, dat, gridBoxL, nodeBoxL, nextIndex, depth + 1, stats);
|
|
else
|
|
stats.updateLeaf(depth + 1, 0);
|
|
if (nr > 0)
|
|
subdivide(right + 1, rightOrig, tempTree, dat, gridBoxR, nodeBoxR, nextIndex + 3, depth + 1, stats);
|
|
else
|
|
stats.updateLeaf(depth + 1, 0);
|
|
}
|
|
|
|
void createNode(List<uint> tempTree, int nodeIndex, int left, int right)
|
|
{
|
|
// write leaf node
|
|
tempTree[nodeIndex + 0] = (uint)((3 << 30) | left);
|
|
tempTree[nodeIndex + 1] = (uint)(right - left + 1);
|
|
}
|
|
|
|
struct buildData
|
|
{
|
|
public uint[] indices;
|
|
public AxisAlignedBox[] primBound;
|
|
public uint numPrims;
|
|
public int maxPrims;
|
|
}
|
|
struct StackNode
|
|
{
|
|
public uint node;
|
|
public float tnear;
|
|
public float tfar;
|
|
}
|
|
public class BuildStats
|
|
{
|
|
public int numNodes;
|
|
public int numLeaves;
|
|
public int sumObjects;
|
|
public int minObjects;
|
|
public int maxObjects;
|
|
public int sumDepth;
|
|
public int minDepth;
|
|
public int maxDepth;
|
|
int[] numLeavesN = new int[6];
|
|
int numBVH2;
|
|
|
|
public BuildStats()
|
|
{
|
|
numNodes = 0;
|
|
numLeaves = 0;
|
|
sumObjects = 0;
|
|
minObjects = 0x0FFFFFFF;
|
|
maxObjects = -1;
|
|
sumDepth = 0;
|
|
minDepth = 0x0FFFFFFF;
|
|
maxDepth = -1;
|
|
numBVH2 = 0;
|
|
|
|
for (int i = 0; i < 6; ++i)
|
|
numLeavesN[i] = 0;
|
|
}
|
|
|
|
public void updateInner() { numNodes++; }
|
|
public void updateBVH2() { numBVH2++; }
|
|
public void updateLeaf(int depth, int n) { }
|
|
public void printStats() { }
|
|
}
|
|
|
|
|
|
AxisAlignedBox bounds;
|
|
List<uint> tree = new List<uint>();
|
|
List<uint> objects = new List<uint>();
|
|
|
|
[StructLayout(LayoutKind.Explicit)]
|
|
public struct FloatToIntConverter
|
|
{
|
|
[FieldOffset(0)]
|
|
public uint IntValue;
|
|
[FieldOffset(0)]
|
|
public float FloatValue;
|
|
}
|
|
|
|
uint floatToRawIntBits(float f)
|
|
{
|
|
FloatToIntConverter converter = new FloatToIntConverter();
|
|
converter.FloatValue = f;
|
|
return converter.IntValue;
|
|
}
|
|
float intBitsToFloat(uint i)
|
|
{
|
|
FloatToIntConverter converter = new FloatToIntConverter();
|
|
converter.IntValue = i;
|
|
return converter.FloatValue;
|
|
}
|
|
|
|
}
|
|
public struct AABound
|
|
{
|
|
public Vector3 lo, hi;
|
|
}
|
|
}
|