Nick Wrote:Might you be willing to share some of that code. I've been reading over the link Frank posted but for some reason I can't seem to wrap my head around how to do that using Objective-C.

The trick I use when working with Objective-C is to avoid it as much as possible

Here's my "get time" function (there are a few discussions on using "mach time" if you search the forum):


And here's my run-frame function, minus some fluff:


That gameRunFrame function is called from the NSTimer callback in my EAGLView class:


Hopefully the other functions (gameStep, gameDrawFrame) are self explanatory. I keep gameTime exposed globally since it's handy to have around everywhere, ditto for gameState. My typical settings for the frame constants are:


So - kGameFrameIntervalNormal is the timer frequency, kGameFrameIntervalIdle is the timer frequency when the app is "idle" (the app delegate decides when to use that). kGameFrameStepInterval is the guaranteed frequency for physics/logic steps and kGameFrameDrawInterval is the maximum frame rate (not guaranteed). Note that I set kGameFrameDrawInterval 10% higher than I actually need it, since you still get some blocking issues with the timer at 120Hz. kGameFrameMaxDelta is there to ensure simulations won't explode when the renderer is bogging - if the game hits that limit it won't be realtime, but at least it won't freeze up or go totally wacky.

I should also note that I don't bother doing any drawing interpolation on the iPhone, since physics updates are never fewer than screen updates. This greatly simplifies gameRunFrame and gameDrawFrame.