nicholaschan.net

This past few days, I’ve been stuck with this problem in my game. Whenever I move my mouse over the render window, the framerate becomes inconsistent and kinetic items in my scene “tears” visually. Even when I remove my mouse detection code, it still happens. I printed out every elapsed time frame and it shows that even frames render at around 0.03 seconds and odd frames render at around 0.0016 seconds. I’m not sure if the problem lies in GLUT or what…

During my CS499 video game development class, I was clueless as to how to approach game timers. For those who aren’t sure what they are used for, game timers are used so that no matter what machine you are on, you want the game to behave constantly. For example, if you were to build a game on your machine now without any timers, your game might run differently on better machines and on older machines.

So far I’ve come across two types of game timers. The first timer goes for full frame-by-frame rendering. This means that no matter what, frames will never be skipped and all machines will render the same amount of frames. This is useful for games that require fast reaction times such as shoot’em up sidescrollers. The downside of this type of timer is that players can run the game on a slower machine and have the advantage of the game render slower so that their character can dodge bullets easier. The second timer allows for constant game timing which I currently have implemented. Since my game requires that the visuals be synchronized with the music, I want my virtual world to be in constant time even if the computer can’t render fast enough. What my game does is that the visual objects’ movement adjusts to the timing in between frames. For example, let’s say I want a cube to move 100 pixels to the right in 10 seconds. If my computer renders at 1 frame per second, the cube will be moving 10 pixels to the right every second. Let’s say that on a slower computer, on frame 6, the computer hiccups and renders at 0.5 frames per second, or 1 frame every 2 seconds. That means on frame 7, my box will be behind by 10 pixels. Since I have my timer implemented, at frame 7 will render just like frame 8 on computer 1 without the hiccups, meaning the box had moved 20 pixels to the right on frame 7. Then at frame 9, my box will be at the destination at the same time as computer 1 with a net drop of 1 frame.