#define ROAD_NUM        512
#define ROAD_WIDTH_BY_2 200
#define CAR_WIDTH_BY_2  100

I64 road_x[ROAD_NUM],road_trend;
F64 speed,distance;
I64 road_ptr=0,car_x;
F64 t_last;
Bool crash;

U0 DrawIt(CTask *task,CDC *dc)
{
  I64 w=task->pix_width,h=task->pix_height;
  I64 i,x,y,xx;
  xx=w>>1-car_x+road_x[road_ptr&(ROAD_NUM-1)];
  dc->color=LTGRAY;
  for (i=0; i<ROAD_NUM; i++)
  {
    x=w>>1-car_x+road_x[(i+road_ptr)&(ROAD_NUM-1)];
    y=h-0.5*i;
    if (y<(h+FONT_HEIGHT)>>1) break;
    GrPlot(dc,x+ROAD_WIDTH_BY_2-0.4*i,y);
    GrPlot(dc,x-ROAD_WIDTH_BY_2+0.4*i,y);
  }
  dc->color=WHITE;
  x=w>>1-CAR_WIDTH_BY_2;
  if (x<xx-ROAD_WIDTH_BY_2)
    crash=TRUE;
  GrLine(dc,x-10,h,x-40,h-100);
  GrLine(dc,x+10,h,x+40,h-100);
  x=w>>1+CAR_WIDTH_BY_2;
  if (x>xx+ROAD_WIDTH_BY_2)
    crash=TRUE;
  GrLine(dc,x-10,h,x-40,h-100);
  GrLine(dc,x+10,h,x+40,h-100);
  dc->color=YELLOW;
  if (crash)
    GrPrint(dc,w>>1-FONT_WIDTH*4,(h-FONT_HEIGHT)>>1,"Game Over");
}

U0 UpdateRoad()
{
  F64 t0=tS;
  distance+=speed*(t0-t_last);
  t_last=t0;
  while (distance>1.0)
  {
    road_trend=ClampI64(road_trend+SignI64(RandU16%3-1),-5,5);
    road_x[road_ptr&(ROAD_NUM-1)]=
    road_x[(road_ptr-1)&(ROAD_NUM-1)]+=road_trend/3;
    road_ptr++;
    distance-=1.0;
  }
}

U0 Init()
{
  I64 i,x=0;
  DocClear;
  "$BG,DKGRAY$%h*c"
  ,(TEXT_ROWS-1)/2,'\n';
  speed=0;
  distance=0;
  road_trend=0;
  road_ptr=0;
  car_x=0;
  for (i=0; i<ROAD_NUM; i++)
  {
    road_x[i]=x;
    road_trend=ClampI64(road_trend+SignI64(RandU16%3-1),-5,5);
    x+=road_trend/3;
  }
  t_last=tS;
  crash=FALSE;
}

U0 Halogen()
{
  I64 arg1,arg2,ch=0,sc=0;
  SettingsPush; //See SettingsPush
  Fs->text_attr=BLACK<<4+WHITE;
  MenuPush(
  "File {"
  "  Abort(,CH_SHIFT_ESC);"
  "  Exit(,CH_ESC);"
  "}"
  "Play {"
  "  Restart(,'\n');"
  "  Accelerate(,,SC_CURSOR_UP);"
  "  Deccellerate(,,SC_CURSOR_DOWN);"
  "  Left(,,SC_CURSOR_LEFT);"
  "  Right(,,SC_CURSOR_RIGHT);"
  "}"
  );
  AutoComplete;
  WinBorder;
  WinMax;
  DocCursor;
  Init;
  Fs->draw_it=&DrawIt;
  try
  {
    while (TRUE)
    {
      switch (ScanMsg(&arg1,&arg2,1<<MSG_KEY_DOWN|1<<MSG_KEY_UP))
      {
      case MSG_KEY_DOWN:
        ch=arg1;
        sc=arg2;
        switch (ch)
        {
        case '\n':
          Init;
          break;
        case CH_ESC:
        case CH_SHIFT_ESC:
          goto ha_done;
        }
        break;
      case MSG_KEY_UP:
        ch=arg1;
        sc=arg2;
        if (!ch)
          switch (sc.u8[0])
          {
          case SC_CURSOR_RIGHT:
          case SC_CURSOR_LEFT:
          case SC_CURSOR_UP:
          case SC_CURSOR_DOWN:
            sc=0;
            break;
          }
        break;
      }
      switch (sc.u8[0])
      {
      case SC_CURSOR_RIGHT:
        car_x++;
        break;
      case SC_CURSOR_LEFT:
        car_x--;
        break;
      case SC_CURSOR_UP:
        if (++speed>200) speed=200;
        break;
      case SC_CURSOR_DOWN:
        if (--speed<0) speed=0;
        break;
      }
      if (crash)
        Snd;
      else
      {
        if (speed)
          Snd(Freq2Ona(speed+10));
        else
          Snd;
        UpdateRoad;
      }
      Sleep(10);
    }
ha_done:
    GetMsg(,,1<<MSG_KEY_UP);
  }
  catch
    PutExcept;
  MenuPop;
  DocClear;
  SettingsPop;
}

Halogen;