wmcube/wmapp/example2/wmradar.cc

   1 #include <cstdlib>
   2 #include <cmath>
   3 #include <sstream>
   4 #include <iomanip>
   5 #include "wmradar.h"
   6 #include "../wmapp.h"
   7
   8 using std::sin;
   9 using std::cos;
  10 using std::atan2;
  11
  12 WMRadar::WMRadar(WMTextBar* t, WMSlider* s)
  13 : angle(0), text_score(t), speed(s)
  14 {
  15   setbuffered(true);
  16   text_score->settext("     0", false);
  17   speed->settotal(50, false);
  18   speed->setvalue(8, false);
  19 }
  20
  21 void
  22 WMRadar::real_display()
  23 {
  24   if (!p_icon())
  25     seticon(false);
  26   setcolor(WMColor(Background));
  27   fill_rectangle(0, 0, b_width(), b_height()); //clear background
  28
  29   setcolor(WMColor(Dim));
  30   for (double i = 0; i < 2 * M_PI; i += M_PI_4)
  31     draw_line(b_width() / 2, b_height() / 2, (1 + cos(i)) * b_width() / 2,
  32         (1 - sin(i)) * b_height() / 2); //draw radial lines
  33
  34   draw_arc(b_width() / 3, b_height() / 3, b_width() / 3 - 1, b_height() / 3 - 1,
  35       0, 360 * 64);
  36   draw_arc(b_width() / 6, b_height() / 6, 2 * b_width() / 3,
  37       2 * b_height() / 3, 0, 360 * 64); //draw circles
  38
  39   setcolor(Color(255, 0, 0));
  40   for (clist::const_iterator i = collisions.begin(); i != collisions.end(); ++i)
  41     fill_arc(i->x - 1, i->y - 1, 3, 3, 0, 360 * 64); //draw collision points
  42
  43   std::vector<X::XPoint> points(3);
  44   for (plist::const_iterator i = planes.begin(); i != planes.end(); ++i)
  45   {
  46     setcolor(Color(0, 255 * i->brightness, 0)); // achieve a fading effect
  47     points[0].x = i->x;
  48     points[0].y = i->y;
  49     points[1].x = int(i->x) + 7 * cos(i->direction + 5.5 * M_PI / 6);
  50     points[1].y = int(i->y) - 7 * sin(i->direction + 5.5 * M_PI / 6);
  51     points[2].x = int(i->x) + 7 * cos(i->direction + 6.5 * M_PI / 6);
  52     points[2].y = int(i->y) - 7 * sin(i->direction + 6.5 * M_PI / 6);
  53     // construct an isoceles triangle pointing in plane's direction of motion
  54     fill_polygon(points); // and draw it
  55   }
  56
  57   setcolor(Color(0, 255, 0));
  58   draw_line(b_width() / 2, b_height() / 2, (1 + cos(angle)) * b_width() / 2,
  59       (1 - sin(angle)) * b_height() / 2); //draw radar line
  60
  61   WMImage::real_display(); //update window
  62 }
  63
  64 double rand(double low, double high)
  65 {
  66   return low + std::rand() * (high - low) / RAND_MAX;
  67 }
  68
  69 void
  70 WMRadar::add_plane()
  71 {
  72   if (planes.size() > 4)
  73     return;
  74
  75   double theta = rand(0, 2 * M_PI); //put plane somewhere along edge
  76   plane p = { (1 + cos(theta)) * b_width() / 2,
  77     (1 - sin(theta)) * b_height() / 2,
  78     rand(theta + 3 * M_PI_4, theta + 5 * M_PI_4), //direction pointing inwards
  79     0.5 }; //brightness
  80
  81   planes.push_back(p);
  82 }
  83
  84 inline double dist2 (double x1, double y1, double x2, double y2)
  85 { //return distance squared between points
  86   return std::pow(x1 - x2, 2) + std::pow(y1 - y2, 2);
  87 }
  88
  89 inline double norm_angle(double angle)
  90 { //return angle shifted into the range [0, 2pi)
  91   return angle - 2 * M_PI * std::floor(angle / (2 * M_PI));
  92 }
  93
  94 bool
  95 WMRadar::release(int, int x, int y)
  96 {
  97   if (wPressed)
  98   {
  99     wPressed = false;
 100     if (contains(x, y) && planes.size())
 101     {
 102       int newx = x - b_left(),
 103           newy = y - b_top();
 104       plist::iterator closest;
 105       double mindist2 = 10000;
 106       for (plist::iterator i = planes.begin(); i != planes.end(); ++i)
 107       {
 108         double d2 = dist2(i->x, i->y, newx, newy);
 109         if (d2 < mindist2)
 110         {
 111           mindist2 = d2;
 112           closest = i;
 113         }
 114       }
 115       closest->direction = norm_angle(atan2(double(int(closest->y) - newy),
 116           double(newx - int(closest->x))));
 117       //change nearest plane's direction towards (x, y)
 118     }
 119     return true;
 120   }
 121   else return false;
 122 }
 123
 124 void
 125 WMRadar::increment_time()
 126 {
 127   for (plist::iterator i = planes.begin(); i != planes.end();)
 128   { //Collision test planes
 129     if (!contains(i->x + left(), i->y + top()))
 130       ++i;
 131     else
 132     {
 133       plist::iterator j = i;
 134       bool collided = false;
 135       for (++j; j != planes.end();)
 136         if (dist2(i->x, i->y, j->x, j->y) <= 0.75)
 137         { //remove each collided plane and increment score
 138           j = planes.erase(j);
 139           collided = true;
 140           increment_score();
 141         }
 142         else
 143           ++j;
 144       if (collided)
 145       {
 146         increment_score();
 147         collision c = { i->x, i->y };
 148         collisions.push_back(c); //make record of collision location
 149         i = planes.erase(i);
 150       }
 151       else
 152         ++i;
 153     }
 154   }
 155
 156   const double angleinc = M_PI / 125;
 157
 158   for (plist::iterator i = planes.begin(); i != planes.end();)
 159   {
 160     double incx = speed->value() * cos(i->direction) / 100;
 161     double incy = -speed->value() * sin(i->direction) / 100;
 162     double nextx = i->x + incx;
 163     double nexty = i->y + incy;
 164
 165     //to check if a plane crossed the radar line, approximate the plane's path
 166     //as an arc:
 167     double& l_start_angle = angle; //make an interval of radar line's angles
 168     const double l_end_angle = l_start_angle + angleinc;
 169
 170     //make an interval of the plane's angles
 171     double p_start_angle = norm_angle(atan2(b_height() / 2 - i->y,
 172           i->x - b_width() / 2));
 173     double p_end_angle = norm_angle(atan2(b_height() / 2 - nexty,
 174           nextx - b_width() / 2));
 175
 176     const double crossp = (b_width() / 2 - i->x) * incy
 177       - (b_height() / 2 - i->y) * incx; //test whether plane is moving in
 178       //a positive or a negative angle
 179     if (crossp < 0.0) //make angle increase counterclockwise
 180     {
 181       const double temp = p_start_angle;
 182       p_start_angle = p_end_angle;
 183       p_end_angle = temp;
 184     }
 185     if (p_end_angle < p_start_angle)
 186       p_end_angle += 2 * M_PI; //make sure end is > start
 187
 188     //intersect radar line interval and plane interval. If result is non-empty,
 189     //there was an intersection.
 190     if (std::min(p_end_angle, l_end_angle)
 191         >= std::max(p_start_angle, l_start_angle))
 192       i->brightness = 1.0; //if plane crossed radar line, make it bright
 193     else
 194       i->brightness *= 0.996; //otherwise decay brightness
 195
 196
 197     i->x = nextx; //update plane's position
 198     i->y = nexty;
 199     if (!WMWidget::contains(i->x + b_left(), i->y + b_top()))
 200       i = planes.erase(i); //cull planes outside of radar
 201     else
 202       ++i;
 203   }
 204
 205   angle = norm_angle(angle + angleinc); //increment radar direction
 206
 207   display();
 208 }
 209
 210 void
 211 WMRadar::increment_score ()
 212 {
 213   using namespace std;
 214   istringstream in(text_score->text()); //get string from textbar
 215   int score;
 216   in >> score; //extract score
 217   ostringstream out;
 218   out << setw(6) << setfill(' ') << score + 1; //increment and put in a string
 219   text_score->settext(out.str()); //put back in textbar
 220 }