source/libr2c2/trackpart.cpp

   1 #include <cmath>
   2 #include <msp/geometry/box.h>
   3 #include <msp/geometry/circle.h>
   4 #include <msp/geometry/extrudedshape.h>
   5 #include <msp/geometry/halfspace.h>
   6 #include <msp/geometry/intersection.h>
   7 #include <msp/geometry/negation.h>
   8 #include <msp/geometry/transformedshape.h>
   9 #include "trackpart.h"
  10
  11 using namespace std;
  12 using namespace Msp;
  13
  14 namespace R2C2 {
  15
  16 TrackPart::TrackPart():
  17         length(0),
  18         radius(0),
  19         path(0),
  20         dead_end(false),
  21         shape(0)
  22 {
  23         links[0] = 0;
  24         links[1] = 0;
  25 }
  26
  27 TrackPart::~TrackPart()
  28 {
  29         delete shape;
  30 }
  31
  32 float TrackPart::get_length() const
  33 {
  34         if(radius)
  35                 return abs(radius)*length;
  36         else
  37                 return length;
  38 }
  39
  40 OrientedPoint TrackPart::get_point(float d) const
  41 {
  42         OrientedPoint result;
  43
  44         if(radius)
  45         {
  46                 Angle a = Angle::from_radians(d/radius);
  47                 result.position = transform.transform(Vector(sin(a)*radius, (1-cos(a))*radius, 0));
  48                 result.rotation = dir+a;
  49         }
  50         else
  51         {
  52                 result.position = transform.transform(Vector(d, 0, 0));
  53                 result.rotation = dir;
  54         }
  55
  56         return result;
  57 }
  58
  59 OrientedPoint TrackPart::get_nearest_point(const Vector &p) const
  60 {
  61         OrientedPoint result;
  62         if(radius)
  63         {
  64                 Vector v = p-transform.transform(Vector(0, radius, 0));
  65                 Angle a = Geometry::atan2(v.y, v.x)+Angle::quarter_turn()-dir;
  66                 if(radius<0)
  67                         a = Angle::half_turn()-a;
  68                 a.wrap_with_base(Angle::from_radians(length/2)-Angle::half_turn());
  69                 a = min(max(a, Angle::zero()), Angle::from_radians(length));
  70                 if(radius<0)
  71                         a = -a;
  72                 result.position = transform.transform(Vector(sin(a)*radius, (1-cos(a))*radius, 0));
  73                 result.rotation = dir+a;
  74         }
  75         else
  76         {
  77                 Vector v = p-pos;
  78                 Vector dir_vec = transform.transform_linear(Vector(1, 0, 0));
  79                 float d = min(max(dot(dir_vec, v), 0.0f), length);
  80                 result.position = pos+dir_vec*d;
  81                 result.rotation = dir;
  82         }
  83         return result;
  84 }
  85
  86 void TrackPart::check_link(TrackPart &other)
  87 {
  88         unsigned n_eps = (dead_end ? 1 : 2);
  89         unsigned n_other_eps = (other.is_dead_end() ? 1 : 2);
  90         for(unsigned i=0; i<n_eps; ++i)
  91         {
  92                 OrientedPoint p1 = get_point(i ? get_length() : 0);
  93                 for(unsigned j=0; j<n_other_eps; ++j)
  94                 {
  95                         OrientedPoint p2 = other.get_point(j ? other.get_length() : 0);
  96
  97                         Vector span = p2.position-p1.position;
  98
  99                         Angle da = wrap_balanced(p2.rotation-p1.rotation+Angle::half_turn()*float((i+j+1)%2));
 100
 101                         if(dot(span, span)<1e-6 && abs(da).radians()<=0.01)
 102                         {
 103                                 links[i] = &other;
 104                                 other.links[j] = this;
 105                                 return;
 106                         }
 107                 }
 108         }
 109 }
 110
 111 TrackPart *TrackPart::get_link(unsigned i) const
 112 {
 113         if(i>=2)
 114                 throw out_of_range("TrackPart::get_link");
 115         return links[i];
 116 }
 117
 118 void TrackPart::create_shape()
 119 {
 120         if(radius)
 121         {
 122                 Geometry::ExtrudedShape<float, 3> ring(
 123                         Geometry::Intersection<float, 2>(
 124                                 Geometry::Circle<float>(abs(radius)+0.02),
 125                                 Geometry::Negation<float, 2>(Geometry::Circle<float>(abs(radius)-0.02))),
 126                         0.01);
 127                 Geometry::HalfSpace<float, 3> start_wall(Vector(-1, 0, 0));
 128                 Geometry::HalfSpace<float, 3> end_wall(rotated_vector(Vector(1, 0, 0),
 129                         Angle::from_radians(length*(radius<0 ? -1 : 1))));
 130                 /* This box only exists so the bounding boxes of curves make sense.  It
 131                 can be removed when libmspmath produces better bounding boxes. */
 132                 float w = sin(length)*(abs(radius)+0.02);
 133                 float h = (1-cos(length))*abs(radius-0.02)+0.04;
 134                 Geometry::TransformedShape<float, 3> bounds(
 135                         Geometry::Box<float>(w, h, 0.01),
 136                         Transform::translation(Vector(w/2, (h/2-0.02)*(radius<0 ? -1 : 1)-radius, 0.005)));
 137                 vector<const Shape *> shapes;
 138                 shapes.push_back(&ring);
 139                 shapes.push_back(&start_wall);
 140                 shapes.push_back(&end_wall);
 141                 shapes.push_back(&bounds);
 142                 shape = new Geometry::TransformedShape<float, 3>(
 143                         Geometry::Intersection<float, 3>::from_iterator_range(shapes.begin(), shapes.end()),
 144                         transform*Transform::translation(Vector(0, radius, 0.005)));
 145         }
 146         else
 147         {
 148                 // TODO Get the track profile dimensions from somewhere
 149                 shape = new Geometry::TransformedShape<float, 3>(
 150                         Geometry::Box<float>(length, 0.04, 0.01),
 151                         transform*Transform::translation(Vector(length/2, 0, 0.005)));
 152         }
 153 }
 154
 155
 156 TrackPart::Loader::Loader(TrackPart &p):
 157         Msp::DataFile::ObjectLoader<TrackPart>(p)
 158 {
 159         add("start",    &Loader::start);
 160         add("length",   &TrackPart::length);
 161         add("radius",   &TrackPart::radius);
 162         add("path",     &TrackPart::path);
 163         add("dead_end", &TrackPart::dead_end);
 164 }
 165
 166 void TrackPart::Loader::finish()
 167 {
 168         if(obj.radius)
 169         {
 170                 obj.length *= M_PI/180;
 171                 obj.radius /= 1000;
 172         }
 173         else
 174                 obj.length /= 1000;
 175
 176         obj.pos /= 1000;
 177
 178         obj.transform = Transform::translation(obj.pos)*
 179                 Transform::rotation(obj.dir, Vector(0, 0, 1));
 180 }
 181
 182 void TrackPart::Loader::start(float x, float y, float d)
 183 {
 184         obj.pos = Vector(x, y, 0);
 185         obj.dir = Angle::from_degrees(d);
 186 }
 187
 188 } // namespace R2C2