f8/cpp/inputgeom.cc
aozhiwei 203adbe1f4 1
2020-08-18 16:11:40 +08:00

264 lines
6.9 KiB
C++

#include "precompile.h"
#include "Recast.h"
#include "inputgeom.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;
}
inline int longestAxis(float x, float y)
{
return y > x ? 1 : 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];
}
}
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;
}
static 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;
}
namespace f8
{
void InputGeom::Init(float width, float height)
{
{
verts_.reserve(3 * 4);
verts_.push_back(0);
verts_.push_back(0);
verts_.push_back(0);
verts_.push_back(0);
verts_.push_back(0);
verts_.push_back(height);
verts_.push_back(width);
verts_.push_back(0);
verts_.push_back(height);
verts_.push_back(width);
verts_.push_back(0);
verts_.push_back(0);
}
{
tris_.push_back(0);
tris_.push_back(1);
tris_.push_back(2);
tris_.push_back(0);
tris_.push_back(2);
tris_.push_back(3);
}
rcCalcBounds(GetVerts(), GetVertCount(), min_, max_);
if (!rcCreateChunkyTriMesh(GetVerts(), GetTris(), GetTriCount(), 256, &chunky_mesh_)) {
abort();
}
}
}