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#include "tetgen_api.h"
#include "tetgen.h"
#include "MEM_guardedalloc.h"
#include <cmath>
#include <algorithm>
#include <sstream>
#include <cstring>
#include <unordered_map>
#include <vector>
void init_tetgenremeshdata(TetGenRemeshData *data)
{
data->in_verts = NULL;
data->in_faces = NULL;
data->in_totverts = 0;
data->in_totfaces = 0;
data->out_verts = NULL;
data->out_facets = NULL;
data->out_tets = NULL;
data->out_totverts = 0;
data->out_totfacets = 0;
data->out_tottets = 0;
}
// Finds the largest edge length of the mesh and computes the volume
// if that were an edge of a tet using (e^3 / (6*sqrt(2)))
//static float compute_maxvol(float *verts, unsigned int *faces, int num_faces)
//{
// auto squared_norm = [](float *v0, float *v1)
// {
// return (v0[0]-v1[0])*(v0[0]-v1[0]) +
// (v0[1]-v1[1])*(v0[1]-v1[1]) +
// (v0[2]-v1[2])*(v0[2]-v1[2]);
// };
// float max_sq_edge_len = 0;
// for (int i=0; i<num_faces; ++i)
// {
// unsigned int f[3] = {faces[i*3], faces[i*3+1], faces[i*3+2]};
// float v0[3] = {verts[f[0]*3], verts[f[0]*3+1], verts[f[0]*3+2]};
// float v1[3] = {verts[f[1]*3], verts[f[1]*3+1], verts[f[1]*3+2]};
// float v2[3] = {verts[f[2]*3], verts[f[2]*3+1], verts[f[2]*3+2]};
// float max_sq_e = std::max(std::max(
// squared_norm(v0,v1),
// squared_norm(v1,v2)),
// squared_norm(v2,v0));
//
// if( max_sq_e > max_sq_edge_len)
// max_sq_edge_len = max_sq_e;
// }
//
// double e = std::sqrt(max_sq_edge_len);
// return (e*e*e) / (6.f*std::sqrt(2.f));
//} // end compute maxvol
static void make_tetgenio(
float *verts,
unsigned int *faces,
int numverts,
int numfaces,
tetgenio &tgio )
{
tgio.initialize();
tgio.firstnumber = 0;
tgio.mesh_dim = 3;
tgio.numberofpoints = numverts;
tgio.pointlist = new REAL[tgio.numberofpoints * 3];
// tgio.pointlist = (REAL *)MEM_malloc_arrayN(
// tgio.numberofpoints, 3 * sizeof(REAL), "tetgen remesh out verts");
for (int i=0; i < tgio.numberofpoints; ++i)
{
tgio.pointlist[i*3+0] = verts[i*3+0];
tgio.pointlist[i*3+1] = verts[i*3+1];
tgio.pointlist[i*3+2] = verts[i*3+2];
}
tgio.numberoffacets = numfaces;
tgio.facetlist = new tetgenio::facet[tgio.numberoffacets];
// tgio.facetlist = (tetgenio::facet *)MEM_malloc_arrayN(
// tgio.numberoffacets, sizeof(tetgenio::facet), "tetgen remesh out facets");
tgio.facetmarkerlist = new int[tgio.numberoffacets];
// tgio.facetmarkerlist = (int *)MEM_malloc_arrayN(
// tgio.numberoffacets, sizeof(int), "tetgen remesh out marker list");
for (int i=0; i<numfaces; ++i)
{
tgio.facetmarkerlist[i] = i;
tetgenio::facet *f = &tgio.facetlist[i];
f->numberofholes = 0;
f->holelist = NULL;
f->numberofpolygons = 1;
f->polygonlist = new tetgenio::polygon[1];
tetgenio::polygon *p = &f->polygonlist[0];
p->numberofvertices = 3;
p->vertexlist = new int[3];
p->vertexlist[0] = faces[i*3+0];
p->vertexlist[1] = faces[i*3+1];
p->vertexlist[2] = faces[i*3+2];
}
}
bool tetgen_resmesh(TetGenRemeshData *tg)
{
// float maxvol = compute_maxvol(tg->in_verts, tg->in_faces, tg->in_totfaces);
// float quality = 1.4;
// Set up the switches
std::stringstream switches;
switches << "Q"; // quiet
// switches << "a" << maxvol;
// if (quality>0)
// switches << "q" << quality;
tetgenio in;
make_tetgenio(tg->in_verts, tg->in_faces, tg->in_totverts, tg->in_totfaces, in);
tetgenio out;
out.initialize();
char *c_switches = (char *)switches.str().c_str();
tetrahedralize(c_switches, &in, &out);
if( out.numberoftetrahedra == 0 || out.numberofpoints == 0 )
{
printf("\n\n\n\n*****FAILED TETGEN\n");
return false;
}
// We'll create our custom list of facets to render
// with blender. These are all of the triangles that
// make up the inner and outer faces, without duplicates.
// To avoid duplicates, we'll hash them as a string.
// While not super efficient, neither is tetrahedralization...
// TODO
struct face {
int f0, f1, f2;
face(int f0_, int f1_, int f2_) : f0(f0_), f1(f1_), f2(f2_) {}
};
auto face_hash = [](int f0, int f1, int f2){
return std::to_string(f0)+" "+std::to_string(f1)+" "+std::to_string(f2);
};
std::unordered_map<std::string,face> faces;
// Tets:
tg->out_tottets = out.numberoftetrahedra;
tg->out_tets = (unsigned int *)MEM_malloc_arrayN(
out.numberoftetrahedra, 4 * sizeof(unsigned int), "tetgen remesh tets");
for (int i=0; i<out.numberoftetrahedra; ++i)
{
tg->out_tets[i*4+0] = out.tetrahedronlist[i*4+0];
tg->out_tets[i*4+1] = out.tetrahedronlist[i*4+1];
tg->out_tets[i*4+2] = out.tetrahedronlist[i*4+2];
tg->out_tets[i*4+3] = out.tetrahedronlist[i*4+3];
// Append faces
for(int j=0; j<4; ++j)
{
int f0 = tg->out_tets[i*4+j];
int f1 = tg->out_tets[i*4+(j+1)%4];
int f2 = tg->out_tets[i*4+(j+2)%4];
std::string hash = face_hash(f0,f1,f2);
if (faces.count(hash)!=0)
continue;
faces.emplace(hash, face(f0,f1,f2));
}
}
// Faces:
tg->out_totfacets = faces.size();
tg->out_facets = (unsigned int *)MEM_malloc_arrayN(
tg->out_totfacets, 3 * sizeof(unsigned int), "tetgen remesh facets");
int f_idx = 0;
for (std::unordered_map<std::string,face>::iterator it = faces.begin();
it != faces.end(); ++it, ++f_idx)
{
tg->out_facets[f_idx*3+0] = it->second.f0;
tg->out_facets[f_idx*3+1] = it->second.f1;
tg->out_facets[f_idx*3+2] = it->second.f2;
}
// Vertices:
tg->out_totverts = out.numberofpoints;
tg->out_verts = (float *)MEM_malloc_arrayN(
out.numberofpoints, 3 * sizeof(float), "tetgen remesh verts");
for (int i=0; i<out.numberofpoints; ++i)
{
tg->out_verts[i*3+0] = out.pointlist[i*3+0];
tg->out_verts[i*3+1] = out.pointlist[i*3+1];
tg->out_verts[i*3+2] = out.pointlist[i*3+2];
}
return true;
}
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