CODEWITHSUNDEEP
androidperformanceunity-game-engineframe-rate
ababab5
ababab5

Reputation: 284

Unity3D Fixed TimeStep - Android FPS issue

I don't understand why, but when I increase the Fixed TimeStep in the Time setting in Unity3D, I have a bad frame issue on Android only.

In iOS, I have a better performance, but Android the animation is very very bad..

Somebody can tell me why increasing the Fixed TimeStep have an issue with the FPS, but on Android, not on iOS.

Upvotes: 2

Views: 4845

Answers (1)

CodeSmile
CodeSmile

Reputation: 64477

A fixed time step of 60 (Hz) means Unity guarantees that the FixedUpdate method runs this many times per second, regardless of framerate. FixedUpdate can be set to run multiple times per frame even.

However you can't force a CPU to do ever more per frame/second. Eventually this will affect the framerate because there isn't enough time to compute and render a frame in the time necessary.

For instance, to get a constant 60 frames per second each frame must be computed and rendered within a 0.01666 second time window. If the computation and rendering takes 0.017 seconds Unity is no longer rendering 60 fps. If vertical synch is enabled (as it is on mobile devices) a constant time per frame of just over 0.01666 means the framerate will be 30 fps (not 55 or something). So on mobile you're more likely to notice the effect of constantly being over the 0.01666 time per frame.

If there are enough FixedUpdate iterations running per second the app has more to compute and thus takes longer per frame. Eventually the FixedUpdate iterations per frame (plus the time it takes to render) no longer complete within 0.01666 seconds, that's what you see as a drop in framerate.

Upvotes: 4

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