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Diffstat (limited to 'Source/AI/chunky_tri_mesh.cpp')
| -rw-r--r-- | Source/AI/chunky_tri_mesh.cpp | 325 |
1 files changed, 325 insertions, 0 deletions
diff --git a/Source/AI/chunky_tri_mesh.cpp b/Source/AI/chunky_tri_mesh.cpp new file mode 100644 index 00000000..0d5b6d1d --- /dev/null +++ b/Source/AI/chunky_tri_mesh.cpp @@ -0,0 +1,325 @@ +//----------------------------------------------------------------------------- +// Name: chunky_tri_mesh.cpp +// Developer: External +// Author: +// Description: This is a utility file from the Recast project which has been +// extracted and modified by Wolfire Games LLC +// License: Read below +//----------------------------------------------------------------------------- + +// +// Copyright (c) 2009-2010 Mikko Mononen memon@inside.org +// +// This software is provided 'as-is', without any express or implied +// warranty. In no event will the authors be held liable for any damages +// arising from the use of this software. +// Permission is granted to anyone to use this software for any purpose, +// including commercial applications, and to alter it and redistribute it +// freely, subject to the following restrictions: +// 1. The origin of this software must not be misrepresented; you must not +// claim that you wrote the original software. If you use this software +// in a product, an acknowledgment in the product documentation would be +// appreciated but is not required. +// 2. Altered source versions must be plainly marked as such, and must not be +// misrepresented as being the original software. +// 3. This notice may not be removed or altered from any source distribution. +// + +#include "chunky_tri_mesh.h" + +#include <stdio.h> +#include <stdlib.h> +#include <math.h> + +struct BoundsItem +{ + float bmin[2]; + float bmax[2]; + int i; +}; + +static int compareItemX(const void* va, const void* vb) +{ + const BoundsItem* a = (const BoundsItem*)va; + const BoundsItem* b = (const BoundsItem*)vb; + if (a->bmin[0] < b->bmin[0]) + return -1; + if (a->bmin[0] > b->bmin[0]) + return 1; + return 0; +} + +static int compareItemY(const void* va, const void* vb) +{ + const BoundsItem* a = (const BoundsItem*)va; + const BoundsItem* b = (const BoundsItem*)vb; + if (a->bmin[1] < b->bmin[1]) + return -1; + if (a->bmin[1] > b->bmin[1]) + return 1; + return 0; +} + +static void calcExtends(const BoundsItem* items, const int /*nitems*/, + const int imin, const int imax, + float* bmin, float* bmax) +{ + bmin[0] = items[imin].bmin[0]; + bmin[1] = items[imin].bmin[1]; + + bmax[0] = items[imin].bmax[0]; + bmax[1] = items[imin].bmax[1]; + + for (int i = imin+1; i < imax; ++i) + { + const BoundsItem& it = items[i]; + if (it.bmin[0] < bmin[0]) bmin[0] = it.bmin[0]; + if (it.bmin[1] < bmin[1]) bmin[1] = it.bmin[1]; + + if (it.bmax[0] > bmax[0]) bmax[0] = it.bmax[0]; + if (it.bmax[1] > bmax[1]) bmax[1] = it.bmax[1]; + } +} + +inline int longestAxis(float x, float y) +{ + return y > x ? 1 : 0; +} + +static void subdivide(BoundsItem* items, int nitems, int imin, int imax, int trisPerChunk, + int& curNode, rcChunkyTriMeshNode* nodes, const int maxNodes, + int& curTri, int* outTris, const int* inTris) +{ + int inum = imax - imin; + int icur = curNode; + + if (curNode > maxNodes) + return; + + rcChunkyTriMeshNode& node = nodes[curNode++]; + + if (inum <= trisPerChunk) + { + // Leaf + calcExtends(items, nitems, imin, imax, node.bmin, node.bmax); + + // Copy triangles. + node.i = curTri; + node.n = inum; + + for (int i = imin; i < imax; ++i) + { + const int* src = &inTris[items[i].i*3]; + int* dst = &outTris[curTri*3]; + curTri++; + dst[0] = src[0]; + dst[1] = src[1]; + dst[2] = src[2]; + } + } + else + { + // Split + calcExtends(items, nitems, imin, imax, node.bmin, node.bmax); + + int axis = longestAxis(node.bmax[0] - node.bmin[0], + node.bmax[1] - node.bmin[1]); + + if (axis == 0) + { + // Sort along x-axis + qsort(items+imin, static_cast<size_t>(inum), sizeof(BoundsItem), compareItemX); + } + else if (axis == 1) + { + // Sort along y-axis + qsort(items+imin, static_cast<size_t>(inum), sizeof(BoundsItem), compareItemY); + } + + int isplit = imin+inum/2; + + // Left + subdivide(items, nitems, imin, isplit, trisPerChunk, curNode, nodes, maxNodes, curTri, outTris, inTris); + // Right + subdivide(items, nitems, isplit, imax, trisPerChunk, curNode, nodes, maxNodes, curTri, outTris, inTris); + + int iescape = curNode - icur; + // Negative index means escape. + node.i = -iescape; + } +} + +bool rcCreateChunkyTriMesh(const float* verts, const int* tris, int ntris, + int trisPerChunk, rcChunkyTriMesh* cm) +{ + int nchunks = (ntris + trisPerChunk-1) / trisPerChunk; + + cm->nodes = new rcChunkyTriMeshNode[nchunks*4]; + if (!cm->nodes) + return false; + + cm->tris = new int[ntris*3]; + if (!cm->tris) + return false; + + cm->ntris = ntris; + + // Build tree + BoundsItem* items = new BoundsItem[ntris]; + if (!items) + return false; + + for (int i = 0; i < ntris; i++) + { + const int* t = &tris[i*3]; + BoundsItem& it = items[i]; + it.i = i; + // Calc triangle XZ bounds. + it.bmin[0] = it.bmax[0] = verts[t[0]*3+0]; + it.bmin[1] = it.bmax[1] = verts[t[0]*3+2]; + for (int j = 1; j < 3; ++j) + { + const float* v = &verts[t[j]*3]; + if (v[0] < it.bmin[0]) it.bmin[0] = v[0]; + if (v[2] < it.bmin[1]) it.bmin[1] = v[2]; + + if (v[0] > it.bmax[0]) it.bmax[0] = v[0]; + if (v[2] > it.bmax[1]) it.bmax[1] = v[2]; + } + } + + int curTri = 0; + int curNode = 0; + subdivide(items, ntris, 0, ntris, trisPerChunk, curNode, cm->nodes, nchunks*4, curTri, cm->tris, tris); + + delete [] items; + + cm->nnodes = curNode; + + // Calc max tris per node. + cm->maxTrisPerChunk = 0; + for (int i = 0; i < cm->nnodes; ++i) + { + rcChunkyTriMeshNode& node = cm->nodes[i]; + const bool isLeaf = node.i >= 0; + if (!isLeaf) continue; + if (node.n > cm->maxTrisPerChunk) + cm->maxTrisPerChunk = node.n; + } + + return true; +} + + +inline bool checkOverlapRect(const float amin[2], const float amax[2], + const float bmin[2], const float bmax[2]) +{ + bool overlap = true; + overlap = (amin[0] > bmax[0] || amax[0] < bmin[0]) ? false : overlap; + overlap = (amin[1] > bmax[1] || amax[1] < bmin[1]) ? false : overlap; + return overlap; +} + +int rcGetChunksOverlappingRect(const rcChunkyTriMesh* cm, + float bmin[2], float bmax[2], + int* ids, const int maxIds) +{ + // Traverse tree + int i = 0; + int n = 0; + while (i < cm->nnodes) + { + const rcChunkyTriMeshNode* node = &cm->nodes[i]; + const bool overlap = checkOverlapRect(bmin, bmax, node->bmin, node->bmax); + const bool isLeafNode = node->i >= 0; + + if (isLeafNode && overlap) + { + if (n < maxIds) + { + ids[n] = i; + n++; + } + } + + if (overlap || isLeafNode) + i++; + else + { + const int escapeIndex = -node->i; + i += escapeIndex; + } + } + + return n; +} + + + +static bool checkOverlapSegment(const float p[2], const float q[2], + const float bmin[2], const float bmax[2]) +{ + static const float EPSILON = 1e-6f; + + float tmin = 0; + float tmax = 1; + float d[2]; + d[0] = q[0] - p[0]; + d[1] = q[1] - p[1]; + + for (int i = 0; i < 2; i++) + { + if (fabsf(d[i]) < EPSILON) + { + // Ray is parallel to slab. No hit if origin not within slab + if (p[i] < bmin[i] || p[i] > bmax[i]) + return false; + } + else + { + // Compute intersection t value of ray with near and far plane of slab + float ood = 1.0f / d[i]; + float t1 = (bmin[i] - p[i]) * ood; + float t2 = (bmax[i] - p[i]) * ood; + if (t1 > t2) { float tmp = t1; t1 = t2; t2 = tmp; } + if (t1 > tmin) tmin = t1; + if (t2 < tmax) tmax = t2; + if (tmin > tmax) return false; + } + } + return true; +} + +int rcGetChunksOverlappingSegment(const rcChunkyTriMesh* cm, + float p[2], float q[2], + int* ids, const int maxIds) +{ + // Traverse tree + int i = 0; + int n = 0; + while (i < cm->nnodes) + { + const rcChunkyTriMeshNode* node = &cm->nodes[i]; + const bool overlap = checkOverlapSegment(p, q, node->bmin, node->bmax); + const bool isLeafNode = node->i >= 0; + + if (isLeafNode && overlap) + { + if (n < maxIds) + { + ids[n] = i; + n++; + } + } + + if (overlap || isLeafNode) + i++; + else + { + const int escapeIndex = -node->i; + i += escapeIndex; + } + } + + return n; +} |