openscad/cgal/polyhole-tessellator-libtess2.cpp

#include <boost/foreach.hpp>
#include <boost/algorithm/string.hpp>
#include <boost/lexical_cast.hpp>
#include <sstream>
#include <fstream>
#include <iostream>
#include <locale.h>

#include "GeometryUtils.h"
#include "Reindexer.h"
#include "linalg.h"
#include "grid.h"
#include "printutils.h"

static void export_stl(const IndexedTriangleMesh &trimesh, std::ostream &output)
{
  setlocale(LC_NUMERIC, "C"); // Ensure radix is . (not ,) in output
  output << "solid OpenSCAD_Model\n";
  const Vector3f *verts = &trimesh.vertices.front();
  BOOST_FOREACH(const IndexedTriangle &t, trimesh.triangles) {
    assert(t[0] < trimesh.vertices.size());
    assert(t[1] < trimesh.vertices.size());
    assert(t[2] < trimesh.vertices.size());

    Vector3f p[3];
    p[0] = verts[t[0]];
    p[1] = verts[t[1]];
    p[2] = verts[t[2]];
    std::stringstream stream;
    stream << p[0][0] << " " << p[0][1] << " " << p[0][2];
    std::string vs1 = stream.str();
    stream.str("");
    stream << p[1][0] << " " << p[1][1] << " " << p[1][2];
    std::string vs2 = stream.str();
    stream.str("");
    stream << p[2][0] << " " << p[2][1] << " " << p[2][2];
    std::string vs3 = stream.str();
    //    if (vs1 != vs2 && vs1 != vs3 && vs2 != vs3) {
      // The above condition ensures that there are 3 distinct vertices, but
      // they may be collinear. If they are, the unit normal is meaningless
      // so the default value of "1 0 0" can be used. If the vertices are not
      // collinear then the unit normal must be calculated from the
      // components.
      Vector3f normal = (p[1] - p[0]).cross(p[2] - p[0]);
      normal.normalize();
      output << "  facet normal " << normal[0] << " " << normal[1] << " " << normal[2] << "\n";
      output << "    outer loop\n";
		
      for (int i=0;i<3;i++) {
        output << "      vertex " << p[i][0] << " " << p[i][1] << " " << p[i][2] << "\n";
      }
      output << "    endloop\n";
      output << "  endfacet\n";
      //    }
  }
  output << "endsolid OpenSCAD_Model\n";
  setlocale(LC_NUMERIC, "");      // Set default locale
}


/*!
  file format: 
  1. polygon coordinates (x,y,z) are comma separated (+/- spaces) and 
  each coordinate is on a separate line
  2. each polygon is separated by one or more blank lines
*/
bool import_polygon(IndexedPolygons &polyhole, const std::string &filename)
{
  Reindexer<Vector3f> uniqueVertices;
  std::ifstream ifs(filename.c_str());
  if (!ifs) return false;

  std::string line;
  IndexedFace polygon;
  while (std::getline(ifs, line)) {
    std::stringstream ss(line);
    double X = 0.0, Y = 0.0, Z = 0.0;
    if (!(ss >> X)) {
      //ie blank lines => flag start of next polygon 
      if (polygon.size() > 0) polyhole.faces.push_back(polygon);
      polygon.clear();
      continue;
    }
    char c = ss.peek();  
    while (c == ' ') {ss.read(&c, 1); c = ss.peek();} //gobble spaces before comma
    if (c == ',') {ss.read(&c, 1); c = ss.peek();} //gobble comma
    while (c == ' ') {ss.read(&c, 1); c = ss.peek();} //gobble spaces after comma
    if (!(ss >> Y)) {
      std::cerr << "Y error\n";
      return false;
    }
    c = ss.peek();
    while (c == ' ') {ss.read(&c, 1); c = ss.peek();} //gobble spaces before comma
    if (c == ',') {ss.read(&c, 1); c = ss.peek();} //gobble comma
    while (c == ' ') {ss.read(&c, 1); c = ss.peek();} //gobble spaces after comma
    if (!(ss >> Z)) {
      std::cerr << "Z error\n";
      return false;
    }
    polygon.push_back(uniqueVertices.lookup(Vector3f(X, Y, Z)));
  }
  if (polygon.size() > 0) polyhole.faces.push_back(polygon);
  ifs.close();
  uniqueVertices.copy(std::back_inserter(polyhole.vertices));
  return true;
}

int main(int argc, char *argv[])
{
  OpenSCAD::debug = "GeometryUtils";

  IndexedPolygons polyhole;
  Vector3f *normal = NULL;
  if (argc >= 2) {
    if (!import_polygon(polyhole, argv[1])) {
      std::cerr << "Error importing polygon" << std::endl;
      exit(1);
    }
    std::cerr << "Imported " << polyhole.faces.size() << " polygons" << std::endl;

    if (argc == 3) {
      std::vector<std::string> strs;
      std::vector<double> normalvec;
      std::string arg(argv[2]);
      boost::split(strs, arg, boost::is_any_of(","));
      assert(strs.size() == 3);
      BOOST_FOREACH(const std::string &s, strs) normalvec.push_back(boost::lexical_cast<double>(s));
      normal = new Vector3f(normalvec[0], normalvec[1], normalvec[2]);
      
   }
  }
  else {
    //construct two non-intersecting nested polygons  
    Reindexer<Vector3f> uniqueVertices;
    IndexedFace polygon1;
    polygon1.push_back(uniqueVertices.lookup(Vector3f(0,0,0)));
    polygon1.push_back(uniqueVertices.lookup(Vector3f(2,0,0)));
    polygon1.push_back(uniqueVertices.lookup(Vector3f(2,2,0)));
    polygon1.push_back(uniqueVertices.lookup(Vector3f(0,2,0)));
    IndexedFace polygon2;
    polygon2.push_back(uniqueVertices.lookup(Vector3f(0.5,0.5,0)));
    polygon2.push_back(uniqueVertices.lookup(Vector3f(1.5,0.5,0)));
    polygon2.push_back(uniqueVertices.lookup(Vector3f(1.5,1.5,0)));
    polygon2.push_back(uniqueVertices.lookup(Vector3f(0.5,1.5,0)));
    polyhole.faces.push_back(polygon1);
    polyhole.faces.push_back(polygon2);
    uniqueVertices.copy(std::back_inserter(polyhole.vertices));
  }

  std::vector<IndexedTriangle> triangles;
  bool ok = GeometryUtils::tessellatePolygonWithHoles(&polyhole.vertices.front(), polyhole.faces, triangles, normal);
  std::cerr << "Tessellated into " << triangles.size() << " triangles" << std::endl;

  IndexedTriangleMesh trimesh;
  trimesh.vertices = polyhole.vertices;
  trimesh.triangles = triangles;

  export_stl(trimesh, std::cout);
}