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!!!!!!!

2. when i resize the viewport, make it smaller, the speed of tank is move more fast than it in bigger viewport.

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.

i don't know. any ideas? thank advance