parse_stl.cpp

#include <cassert>
#include <fstream>
#include <iostream>
#include <sstream>
#include <streambuf>

#include "parse_stl.h"

namespace stl {

  std::ostream& operator<<(std::ostream& out, const point p) {
    out << "(" << p.x << ", " << p.y << ", " << p.z << ")" << std::endl;
    return out;
  }

  std::ostream& operator<<(std::ostream& out, const triangle& t) {
    out << "---- TRIANGLE ----" << std::endl;
    out << t.normal << std::endl;
    out << t.v1 << std::endl;
    out << t.v2 << std::endl;
    out << t.v3 << std::endl;
    return out;
  }
  
  float parse_float(std::ifstream& s) {
    char f_buf[sizeof(float)];
    s.read(f_buf, 4);
    float* fptr = (float*) f_buf;
    return *fptr;
  }

  point parse_point(std::ifstream& s) {
    float x = parse_float(s);
    float y = parse_float(s);
    float z = parse_float(s);
    return point(x, y, z);
  }

  stl_data parse_stl(const std::string& stl_path) {
    std::ifstream stl_file(stl_path.c_str(), std::ios::in | std::ios::binary);
    if (!stl_file) {
      std::cout << "ERROR: COULD NOT READ FILE" << std::endl;
      assert(false);
    }

    char header_info[80] = "";
    char n_triangles[4];
    stl_file.read(header_info, 80);
    stl_file.read(n_triangles, 4);
    std::string h(header_info);
    stl_data info(h);
    unsigned int* r = (unsigned int*) n_triangles;
    unsigned int num_triangles = *r;
    for (unsigned int i = 0; i < num_triangles; i++) {
      auto normal = parse_point(stl_file);
      auto v1 = parse_point(stl_file);
      auto v2 = parse_point(stl_file);
      auto v3 = parse_point(stl_file);
      info.triangles.push_back(triangle(normal, v1, v2, v3));
      char dummy[2];
      stl_file.read(dummy, 2);
    }
    return info;
  }

}