source/3d/tracktype.cpp

   1 #include <algorithm>
   2 #include <cmath>
   3 #include <msp/gl/technique.h>
   4 #include "catalogue.h"
   5 #include "tracktype.h"
   6
   7 using namespace std;
   8 using namespace Msp;
   9
  10 namespace {
  11
  12 bool compare_z(const R2C2::Vector &p1, const R2C2::Vector &p2)
  13 {
  14         return p1.z<p2.z;
  15 }
  16
  17 template<typename Iter>
  18 Iter graham_scan(Iter begin, Iter end)
  19 {
  20         // http://en.wikipedia.org/wiki/Graham_scan
  21
  22         // Find point with lowest X coordinate
  23         R2C2::Vector lowest = *begin;
  24         for(Iter i=begin; i!=end; ++i)
  25                 if(i->x<lowest.x || (i->x==lowest.x && i->y>lowest.y))
  26                         lowest = *i;
  27
  28         // Compute tangents and sort points
  29         for(Iter i=begin; i!=end; ++i)
  30                 i->z = (i->x==lowest.x ? 1e5/(i->y-lowest.y-1) : (i->y-lowest.y)/(i->x-lowest.x));
  31         sort(begin, end, compare_z);
  32
  33         for(Iter k=begin, i=k++, j=k++;; )
  34         {
  35                 // Compute winding by cross product
  36                 float turn = cross(*j-*i, *k-*j).z;
  37
  38                 if(turn<1e-5)
  39                 {
  40                         // Right turn - throw the middle point away
  41                         // Special case for collinear vertices in the beginning
  42                         if(i==begin)
  43                                 j = k++;
  44                         else
  45                                 j = i--;
  46                 }
  47                 else
  48                 {
  49                         // Left turn - store the middle point and advance
  50                         if(++i!=j)
  51                                 *i = *j;
  52                         j = k++;
  53                 }
  54
  55                 // Cycle back to beginning and terminate after checking the last point
  56                 if(k==end)
  57                         k = begin;
  58                 else if(j==begin)
  59                         return ++i;
  60         }
  61 }
  62
  63 }
  64
  65 namespace R2C2 {
  66
  67 TrackType3D::TrackType3D(Catalogue3D &cat3d, const TrackType &tt):
  68         catalogue(cat3d),
  69         mesh(0),
  70         object(0)
  71 {
  72         const Catalogue &cat = cat3d.get_catalogue();
  73         const vector<TrackPart> &parts = tt.get_parts();
  74
  75         const Profile &ballast_profile = cat.get_ballast_profile();
  76         const Vector &ballast_min = ballast_profile.get_min_coords();
  77         const Vector &ballast_max = ballast_profile.get_max_coords();
  78         float ballast_h = ballast_max.y-ballast_min.y;
  79
  80         const Profile &rail_profile = cat.get_rail_profile();
  81         const Vector &rail_min = rail_profile.get_min_coords();
  82         const Vector &rail_max = rail_profile.get_max_coords();
  83         float rail_h = rail_max.y-rail_min.y;
  84
  85         float gauge = cat.get_gauge();
  86
  87         string obj_name = tt.get_object();
  88         if(!obj_name.empty())
  89         {
  90                 object = &catalogue.get<GL::Object>(obj_name);
  91                 const GL::Mesh *m = object->get_mesh();
  92                 const GL::VertexArray &vertices = m->get_vertices();
  93                 int vertex_offs = vertices.get_format().offset(GL::VERTEX2);
  94                 if(vertex_offs>=0)
  95                 {
  96                         for(unsigned i=0; i<vertices.size(); ++i)
  97                         {
  98                                 const float *v = vertices[i]+vertex_offs;
  99                                 border.push_back(Vector(v[0], v[1], 0));
 100                         }
 101                 }
 102         }
 103         else
 104         {
 105                 mesh = new GL::Mesh((GL::NORMAL3, GL::TEXCOORD2, GL::VERTEX3));
 106                 mesh->set_winding(&GL::WindingTest::counterclockwise());
 107                 GL::MeshBuilder bld(*mesh);
 108
 109                 unsigned index = 0;
 110                 bld.texcoord(0.25, 0.5);
 111                 for(vector<TrackPart>::const_iterator i=parts.begin(); i!=parts.end(); ++i)
 112                         build_part(*i, ballast_profile, Vector(0, -ballast_min.y, 0), false, bld, index);
 113
 114                 bld.texcoord(0.75, 0.5);
 115                 float y = ballast_h-rail_min.y;
 116                 for(vector<TrackPart>::const_iterator i=parts.begin(); i!=parts.end(); ++i)
 117                         build_part(*i, rail_profile, Vector(0, gauge/2, y), true, bld, index);
 118                 for(vector<TrackPart>::const_iterator i=parts.begin(); i!=parts.end(); ++i)
 119                         build_part(*i, rail_profile, Vector(0, -gauge/2, y), false, bld, index);
 120
 121                 object = new GL::Object;
 122                 object->set_mesh(mesh);
 123                 object->set_technique(&catalogue.get<GL::Technique>(cat.get_track_technique()));
 124         }
 125
 126         unsigned paths = tt.get_paths();
 127         for(unsigned i=0; paths; ++i, paths>>=1)
 128         {
 129                 GL::Mesh *m = 0;
 130                 if(paths&1)
 131                 {
 132                         m = new GL::Mesh(GL::VERTEX3);
 133                         GL::MeshBuilder bld(*m);
 134                         unsigned index = 0;
 135                         for(vector<TrackPart>::const_iterator j=parts.begin(); j!=parts.end(); ++j)
 136                                 if(j->get_path()==i)
 137                                         build_part(*j, cat.get_path_profile(), Vector(0, 0, ballast_h+1.5*rail_h), false, bld, index);
 138                 }
 139                 path_meshes.push_back(m);
 140         }
 141
 142         min_z = max_z = border.front().z;
 143         for(vector<Vector>::iterator i=border.begin(); i!=border.end(); ++i)
 144         {
 145                 min_z = min(min_z, i->z);
 146                 max_z = max(max_z, i->z);
 147         }
 148         border.erase(graham_scan(border.begin(), border.end()), border.end());
 149 }
 150
 151 TrackType3D::~TrackType3D()
 152 {
 153         for(vector<GL::Mesh *>::iterator i=path_meshes.begin(); i!=path_meshes.end(); ++i)
 154                 delete *i;
 155 }
 156
 157 void TrackType3D::get_bounds(const Angle &angle, Vector &minp, Vector &maxp) const
 158 {
 159         Transform trans = Transform::rotation(-angle, Vector(0, 0, 1));
 160
 161         minp = maxp = Vector();
 162         minp.z = min_z;
 163         maxp.z = max_z;
 164
 165         for(vector<Vector>::const_iterator i=border.begin(); i!=border.end(); ++i)
 166         {
 167                 Vector v = trans.transform(*i);
 168
 169                 minp.x = min(minp.x, v.x);
 170                 minp.y = min(minp.y, v.y);
 171                 maxp.x = max(maxp.x, v.x);
 172                 maxp.y = max(maxp.y, v.y);
 173         }
 174 }
 175
 176 const GL::Mesh &TrackType3D::get_path_mesh(unsigned p) const
 177 {
 178         if(p>=path_meshes.size())
 179                 throw out_of_range("TrackType3D::get_path_mesh");
 180         if(!path_meshes[p])
 181                 throw invalid_argument("TrackType3D::get_path_mesh");
 182         return *path_meshes[p];
 183 }
 184
 185 void TrackType3D::build_part(const TrackPart &part, const Profile &profile, const Vector &offset, bool mirror, GL::MeshBuilder &bld, unsigned &base_index)
 186 {
 187         float plen = part.get_length();
 188         unsigned nsegs = (part.is_curved() ? static_cast<unsigned>(plen*32)+1 : 1);
 189
 190         unsigned n_vertices = profile.get_n_vertices();
 191         for(unsigned i=0; i<=nsegs; ++i)
 192         {
 193                 TrackPoint basep = part.get_point(i*plen/nsegs);
 194                 Transform trans = Transform::rotation(basep.dir, Vector(0, 0, 1));
 195
 196                 for(unsigned j=0; j<n_vertices; ++j)
 197                 {
 198                         const Profile::Vertex &v = profile.get_vertex(mirror ? n_vertices-1-j : j);
 199                         Vector p(0, -v.pos.x, v.pos.y);
 200                         if(mirror)
 201                                 p.y = -p.y;
 202                         p = basep.pos+trans.transform(offset+p);
 203
 204                         Vector n(0, -v.normal.x, v.normal.y);
 205                         if(mirror)
 206                                 n.y = -n.y;
 207                         n = trans.transform(n);
 208
 209                         bld.normal(n.x, n.y, n.z);
 210                         bld.vertex(p.x, p.y, p.z);
 211
 212                         border.push_back(p);
 213                 }
 214         }
 215
 216         for(unsigned i=0; i+1<n_vertices; )
 217         {
 218                 bld.begin(GL::TRIANGLE_STRIP);
 219                 for(unsigned j=0; j<=nsegs; ++j)
 220                 {
 221                         unsigned k = j*n_vertices+i;
 222                         bld.element(base_index+k+1);
 223                         bld.element(base_index+k);
 224                 }
 225                 bld.end();
 226
 227                 ++i;
 228                 if(!profile.get_vertex(i).smooth)
 229                         ++i;
 230         }
 231
 232         base_index += (nsegs+1)*n_vertices;
 233 }
 234
 235 } // namespace R2C2