irregular fps

Are you moving around the world? Do you have dynamic objects that are moving around the world? Basically, does the polygon count fluctuate alot? If so, you can solve that with frustum culling... I had a similar issue..

no its a static camera, with just objects in front of camera, no objects are even half on screen half off. Its not a game really, its a simple app. Nothing is moving except one object which rotates about the y axis. But because of this jumpiness in frame rate, the rotation looks really jumpy.

Hi Stewypeza,

How do you calculate your frame rate? You say it fluctuates within a second which leads me to assume your calculating the frame rate based on the amount of time it takes to render a single frame. From my experience your probably not doing anything wrong, you might be hitting a V-Sync boundary so that you have to wait until the next monitor refresh to begin rendering the next frame. It might be worth while calculating the frame rate as an average over a number of frames.

You can then use the calculated frame rate to smooth your rotation. If you know how may degrees you want to rotate per second then you just multiply this by 1.0f / Frame Rate for the amount you want to rotate per frame.



Richard.

I calculate the frame rate by finding the time difference between the render method being called. The code is shown below



The rotation is done in a similar way to how you suggested as shown below




However as the frame rate drops to 20, the rotation of the objects visually looks really jumpy comapred to at 60 fps.

The frame rate always seems to be 66 max and 21 at the least as tho it is capped somehow but i havent implemented it to be restricted.

Also in theory even with 20 frames per second, an object rotating should still look smooth but in my app it looks very jumpy. Ive never come across something like this before and i am stumped. Any ideas or solutions much appreciated?

Try making everything in your framerate calculation 'float', just temporarily. Sometimes you think you're casting to float when you aren't. Since you're getting repetitive frame rates, I suspect that it's worth a shot to try all floats.