/*************************************************************
 *** PongTime - Make a bouncy clock. Randomize speed after ***
 ***            each bounce, within limites                ***
 *************************************************************/

#define  COL_AVERAGE_MOVE  3           // average column movement
#define  ROW_AVERAGE_MOVE  3           // average row movement
#define  COL_RANDOM_DELTA  1           // allowed change from average move to
#define  ROW_RANDOM_DELTA  1           // randomize the bounces


#include <WinUtil.lib>  // Lots of useful routines
#include <Message.lib>  // Send messages to windows

window = spawn(P_NOWAIT,"CLOCK.EXE");
if ( window != NULL ) {

   // Get size of the screen
   ScreenWidth = GetSystemMetrics(SM_CXSCREEN);
   ScreenHeight = GetSystemMetrics(SM_CYSCREEN);
 
   // will make window fill 1/4 of the screen height
   WinWidth = WinHeight = ScreenHeight / 4;

   // Get Initial position of the window
   WindowCol = GetWindowRect(window).left;
   WindowRow = GetWindowRect(window).top;

   // determine maximum and minimum values for Col and Row before bouncing
   MinCol = 0;
   MinRow = 0;
   MaxCol = ScreenWidth - WinWidth;
   MaxRow = ScreenHeight - WinHeight;

   // start random direction and delta
   srand();
   ColSpeed = GetRandomSpeed(COL_AVERAGE_MOVE,COL_RANDOM_DELTA,rand() & 1);
   RowSpeed = GetRandomSpeed(ROW_AVERAGE_MOVE,ROW_RANDOM_DELTA,rand() & 1);

   // Finally, keep bouncing the window around at every interval
   while ( IsWindow(window) ) {

      // move window to new Row and Col position
      MoveWindow(window,WindowCol += ColSpeed,WindowRow += RowSpeed,
                 WinWidth,WinHeight,TRUE);

      // check if needs to bounce back to to hitting desktop edge
      if ( ColSpeed < 0 ) {
         if ( WindowCol < MinCol )
            ColSpeed = GetRandomSpeed(COL_AVERAGE_MOVE,COL_RANDOM_DELTA,TRUE);
      } else {
         if ( MaxCol < WindowCol )
            ColSpeed = GetRandomSpeed(COL_AVERAGE_MOVE,COL_RANDOM_DELTA,FALSE);
      }
      if ( RowSpeed < 0 ) {
         if ( WindowRow < MinRow )
            RowSpeed = GetRandomSpeed(ROW_AVERAGE_MOVE,ROW_RANDOM_DELTA,TRUE);
      } else {
         if ( MaxRow < WindowRow )
            RowSpeed = GetRandomSpeed(ROW_AVERAGE_MOVE,ROW_RANDOM_DELTA,FALSE);
      }

   }

}



//****** ROUTINES CALLED BY THE ABOVE CODE *******

GetRandomSpeed(average,deviation,positive) // if not positive then negative
{
   // get a random deviation from average
   deviate = (rand() % (2*deviation + 1)) - deviation;

   if ( positive )
      return( average + deviate );
   else
      return( -average - deviate );
}

IsWindow(WindowHandle)
{
   return DynamicLink("USER","ISWINDOW",SWORD16,PASCAL,WindowHandle);
}