Ball should bounce of edges, sometimes just glitches.

Martin1209

Hello there, I am creating an air hockey style game, and I am having an issue with the 'puck' bouncing off the sides. I have the code below(and the corresponding one for Y direction).

  pX += pSpX*pDirX;
  if (pX > width-pRad/2 || pX < 0+pRads/2) 
  {
    pDirX = -pDirX;
    pSpX = 0.8*pSpX;
    if(pSpX < 0.4)
    {
    pSpX = 0.4;
    }
  }

The intention is that when the puck hits the side, the direction will reverse, and the 'speed' will decrease by a chunk each time it hits a side. When I first did this, I noticed that as it slowed down it would sometimes just glitch and move only along an axis. I tried to add a 'minimum' function(speed never less than 0.4) which seems to have decreased the occurrence of this, but it still happens and with no apparent pattern to me. Would anyone be able to advise as to why this happens , and how I could fix it?

TfGuy44

Your puck is getting stuck. It's trying to bounce back, but it's not going fast enough to get away from the wall on the next frame. The fix is to set the puck's position to the boundry value when it bounces:

if( puck_position > wall_boundry ){
  puck_position = wall_boundry;
  puck_direction *= -1;
}

Martin1209

Thank you very much, you are spot on!