   what is the proper time out for rending 2D
  hi guys I have this problem that i try to resolve it for few days, but no progress. i don't even know is that possible to resolve.i am writting a Tank game. i have a main timer move all the items in the scene. QObject::startTimer(20);I have a tank move in the scene, and i use graphicsView.ensureVisible to keep it around center of viewport. so the scene is big (5000,5000) viewport is about 1000,1000, viewport will move when tank moves out of center rect. i set tank move 10 pixels very timer trigger. the problem is when tank moves, it become fuzzy.when i change it to 3 pixels, it is not fuzzy, but it was very slow, i need to make it move fast. It is tank, not the ant. So I change the timer to startTimer(3). It works good if the Tank move inside of center rect(viewport is not move). 1. but when viewport moves, tank is slow down!!!!!!!i think it may has something to do with the speed of paint. the bigger view port takes longer to paint, so 3 millisecond is not enough for it to paint.    
  Although it can probably be inferred from your post, it would be helpful if you told us what programming language and APIs you're using.   ;  I use c++, API is Qt   