C++ MeshType::triangle_begin方法代码示例

 std::pair<double, double> operator()(MeshType& mesh) const {
     double max_height = derived().initialize_node_values(mesh);
     
     double min_edge_length = (*mesh.edge_begin()).length();
     for (auto eit = mesh.edge_begin(); eit != mesh.edge_end(); ++eit) {
         min_edge_length = std::min(min_edge_length, (*eit).length());
     }
 
     for (auto tri_it = mesh.triangle_begin(); tri_it != mesh.triangle_end(); ++tri_it) {
         (*tri_it).value() = ((*tri_it).node(0).value() + (*tri_it).node(1).value() + (*tri_it).node(2).value()) / 3.0;
     }
     return std::make_pair(max_height, min_edge_length);
 }

int main(int argc, char* argv[])
{
  // Check arguments
  if (argc < 3) {
    std::cerr << "Usage: shallow_water NODES_FILE TRIS_FILE\n";
    exit(1);
  }

  MeshType mesh;
  // HW4B: Need node_type before this can be used!
#if 1
  std::vector<typename MeshType::node_type> mesh_node;
#endif

  // Read all Points and add them to the Mesh
  std::ifstream nodes_file(argv[1]);
  Point p;
  while (CS207::getline_parsed(nodes_file, p)) {
    // HW4B: Need to implement add_node before this can be used!
#if 1
    mesh_node.push_back(mesh.add_node(p));
#endif
  }

  // Read all mesh triangles and add them to the Mesh
  std::ifstream tris_file(argv[2]);
  std::array<int,3> t;
  while (CS207::getline_parsed(tris_file, t)) {
    // HW4B: Need to implement add_triangle before this can be used!
#if 1
    mesh.add_triangle(mesh_node[t[0]], mesh_node[t[1]], mesh_node[t[2]]);
#endif
  }

  // Print out the stats
  std::cout << mesh.num_nodes() << " "
            << mesh.num_edges() << " "
            << mesh.num_triangles() << std::endl;

  // HW4B Initialization
  // Set the initial conditions according the type of input pattern
  if(argv[2][5]=='d'){
    Dam<MeshType> init;
    for(auto it= mesh.node_begin(); it != mesh.node_end(); ++it)
      init(*it);
    }
  else if((argv[2][5]=='p')){
    Pebble<MeshType> init;
    for(auto it= mesh.node_begin(); it != mesh.node_end(); ++it)
      init(*it);
    }
  else{
    Wave<MeshType> init;
    for(auto it= mesh.node_begin(); it != mesh.node_end(); ++it)
      init(*it);
    }

  // Set triangle values
  for (auto it=mesh.triangle_begin(); it!=mesh.triangle_end(); ++it) {
    (*it).value().Q = QVar(0.0,0.0,0.0);
    (*it).value().Q += (*it).node(0).value().Q;
    (*it).value().Q += (*it).node(1).value().Q;
    (*it).value().Q += (*it).node(2).value().Q;
    (*it).value().Q /= 3.0;
  }
 

  // Launch the SDLViewer
  CS207::SDLViewer viewer;
  viewer.launch();


  // HW4B: Need to define Mesh::node_type and node/edge iterator
  // before these can be used!
#if 1
  auto node_map = viewer.empty_node_map(mesh);
  viewer.add_nodes(mesh.node_begin(), mesh.node_end(),
                   CS207::DefaultColor(), NodePosition(), node_map);
  viewer.add_edges(mesh.edge_begin(), mesh.edge_end(), node_map);
#endif
  viewer.center_view();


  // HW4B: Timestep
  // CFL stability condition requires dt <= dx / max|velocity|
  // For the shallow water equations with u = v = 0 initial conditions
  //   we can compute the minimum edge length and maximum original water height
  //   to set the time-step
  // Compute the minimum edge length and maximum water height for computing dt
  double min_edge_length =( *mesh.edge_begin()).length();
  for (auto it=mesh.edge_begin(); it!=mesh.edge_end(); ++it) {
    if ((*it).length() < min_edge_length) {
      min_edge_length = (*it).length();
    }
  }
  double max_height = 0.0;
  for (auto it=mesh.node_begin(); it!=mesh.node_end(); ++it) {
    if ((*it).value().Q.h > max_height) {
      max_height = (*it).value().Q.h;
    }
//.........这里部分代码省略.........

int main(int argc, char* argv[]) {
  // Check arguments
  if (argc < 2) {
    std::cerr << "Usage: " << argv[0] << " NODES_FILE TETS_FILE\n";
    exit(1);
  }

  MeshType mesh;
  std::vector<typename MeshType::node_type> nodes;

  // Create a nodes_file from the first input argument
  std::ifstream nodes_file(argv[1]);
  
  // Interpret each line of the nodes_file as a 3D Point and add to the Mesh
  Point p;
  while (CS207::getline_parsed(nodes_file, p))
    nodes.push_back(mesh.add_node(p));

  // Create a trianges_file from the second input argument
  std::ifstream triangles_file(argv[2]);

  // Interpret each line of the tets_file as three ints which refer to nodes
  std::array<int,3> t;


  // add in the triangles
  while (CS207::getline_parsed(triangles_file, t))
    for (unsigned i = 1; i < t.size(); ++i)
      for (unsigned j = 0; j < i; ++j)
        for (unsigned k = 0; k < j; ++k)
        {
          mesh.add_triangle(nodes[t[i]], nodes[t[j]], nodes[t[k]]);
      }   

  // Set masses of nodes equal to 1/N where N is the number of nodes
  // and the initial velocities to 0. Also, get the indexes of
  // the nodes at positions (1,0,0) and (0,0,0)
  for(auto it=mesh.node_begin(); it != mesh.node_end(); ++ it)
  {
      (*it).value().mass = total_mass/mesh.num_nodes();
      (*it).value().velocity = Point(0.0,0.0,0.0);
  }

  // Set spring constants for each node equal to spring_const variable
  // and set initial length values equal to lengths of edges prior to
  // running the symplectic Euler steps
  for(auto it=mesh.edge_begin(); it != mesh.edge_end(); ++ it)
  {
      (*it).value().spring_constant = spring_const;
      (*it).value().initial_length = (*it).length();
  }


  // Set the triangle direction values so that we can determine which 
  // way to point normal vectors. This part assumes a convex shape
  Point center = get_center(mesh);
  for(auto it=mesh.triangle_begin(); it != mesh.triangle_end(); ++ it)
  {  
  	//std::cout << (*it).index() << std::endl;
  	set_normal_direction((*it),center);
  }

  // Print out the stats
  std::cout << mesh.num_nodes() << " " << mesh.num_edges() << std::endl;

  std::cout << "Center: " << get_center(mesh) << std::endl;
  // Launch the SDLViewer
  CS207::SDLViewer viewer;
  auto node_map = viewer.empty_node_map(mesh);
  viewer.launch();

  viewer.add_nodes(mesh.node_begin(), mesh.node_end(), node_map);
  viewer.add_edges(mesh.edge_begin(), mesh.edge_end(), node_map);

  viewer.center_view();

  // Begin the mass-spring simulation
  double dt = 0.0001;
  double t_start = 0;
  double t_end = 20.0;
  

  // Initialize constraints
  PlaneConstraint c1;
  //SelfCollisionConstraint c2;
  //auto combined_constraints = make_combined_constraints(c1,c2);
  


  for (double t = t_start; t < t_end; t += dt) {
    MassSpringForce ms_force;
    PressureForce p_force = PressureForce(0.0);
    DampingForce d_force = DampingForce(mesh.num_nodes());
    GravityForce g_force;
    WindForce w_force;

    (void) d_force; // prevents compiler from throwing error for unused variable
      
    
    if (t >= t_addgas - dt) {
//.........这里部分代码省略.........

int main(int argc, char* argv[]) {
  // Check arguments
  if (argc < 5) {
    std::cerr << "Usage: final_project NODES_FILE TRIS_FILE ball.nodes ball.tris \n";
    exit(1);
  }

  MeshType mesh;
  std::vector<typename MeshType::node_type> mesh_node;

  // Read all water Points and add them to the Mesh
  std::ifstream nodes_file(argv[1]);
  Point p;
  uint water_nodes = 0;
  while (CS207::getline_parsed(nodes_file, p)) {
    mesh_node.push_back(mesh.add_node(p));
    water_nodes++;
  }

  // Read all water mesh triangles and add them to the Mesh
  std::ifstream tris_file(argv[2]);
  std::array<int,3> t;
  int water_tris = 0;
  while (CS207::getline_parsed(tris_file, t)) {
    mesh.add_triangle(mesh_node[t[0]], mesh_node[t[1]], mesh_node[t[2]]);
    water_tris++;
  }
  uint water_edges = mesh.num_edges();

  std::ifstream nodes_file2(argv[3]);
  double radius = 1 * scale;
  while (CS207::getline_parsed(nodes_file2, p)) {
    p *= scale;
    p.z += + start_height;
    mesh_node.push_back(mesh.add_node(p));
  }

  // Read all ball mesh triangles and add them to the mesh
  std::ifstream tris_file2(argv[4]);
  while (CS207::getline_parsed(tris_file2, t)) {
    mesh.add_triangle(mesh_node[t[0]+water_nodes], mesh_node[t[1]+water_nodes], mesh_node[t[2]+water_nodes]);
  }

  // Print out the stats
  std::cout << mesh.num_nodes() << " "
            << mesh.num_edges() << " "
            << mesh.num_triangles() << std::endl;

  /* Set the initial conditions */ 
  // Set the initial values of the nodes and get the maximum height double
  double max_h = 0;
  double dx = 0;
  double dy = 0;
  auto init_cond = Still();
  auto b_init_cond = Cone(); 

  // Find the maximum height and apply initial conditions to nodes
  for (auto it = mesh.node_begin(); it != mesh.node_end(); ++it) { 
    auto n = *it;
    if (n.index() < water_nodes){
	    n.value().q = init_cond(n.position());
	    n.value().b = b_init_cond(n.position());
	    max_h = std::max(max_h, n.value().q.h);
  	}
  	else {
  		n.value().q = QVar(n.position().z, 0, 0);
      n.value().mass = total_mass/(mesh.num_nodes() - water_nodes);
      n.value().velocity = Point(0.0,0.0,0.0);
  	}
  } 

  // Set the initial values of the triangles to the average of their nodes and finds S
  // Set the triangle direction values so that we can determine which 
  // way to point normal vectors. This part assumes a convex shape
  Point center = get_center(mesh); 
  for (auto it = mesh.triangle_begin(); it != mesh.triangle_end(); ++it) {
    auto t = *it; 
    if (t.index() < water_tris){
	    t.value().q_bar = (t.node1().value().q + 
	                       t.node2().value().q + 
	                       t.node3().value().q) / 3.0;
	    t.value().q_bar2 = t.value().q_bar;

	    double b_avg = (t.node1().value().b + 
	                    t.node2().value().b + 
	                    t.node3().value().b) / 3.0;
	    // finds the max dx and dy to calculate Source
	    dx = std::max(dx, fabs(t.node1().position().x - t.node2().position().x));
	    dx = std::max(dx, fabs(t.node2().position().x - t.node3().position().x));
	    dx = std::max(dx, fabs(t.node3().position().x - t.node1().position().x));
	    dy = std::max(dy, fabs(t.node1().position().y - t.node2().position().y));
	    dy = std::max(dy, fabs(t.node2().position().y - t.node3().position().y));
	    dy = std::max(dy, fabs(t.node3().position().y - t.node1().position().y));
	    t.value().S = QVar(0, -grav * t.value().q_bar.h * b_avg / dx, -grav * t.value().q_bar.h * b_avg / dy);
	  } 
    else
      set_normal_direction((*it),center);
  }

  // Calculate the minimum edge length and set edge inital condititons
//.........这里部分代码省略.........