Why is the visible framerate of my JavaFX 2 application so unreliable?

Question

I have to decide whether JavaFX (2) is the correct UI toolkit for a gaming platform we're about to build. The games are simple 2D games, nothing very fancy, but for the user experience it is important that the games look "smooth".

Currently, I'm having some concerns about the frame rate exhibited by a simple test application (moving some sprites in ImageViews around).

• When running the application on my main monitor, the smoothness of the application drops noticeably when doing something with my mouse on my second monitor. This continues for a few seconds, then returns to normal.
• The application never achieves the same level of smoothness on my second monitor as it does on my main monitor.
• Note that this is about frame rate differences visible to the human eye. For some reason, the internal frame rate (as reported by PerformanceTracker.getAverageFPS() or the JavaFX Balls demo application) does not go down (in fact, the reported number even goes up by a couple frames: normally it's running around ~128fps, when the animation looks like it's stuttering the reported fps is ~131). This is with javafx.animation.fullspeed=true.
• When I have a Flash animation open in the background, the JavaFX application never achieves smooth animation, even though the CPU is not contested (my CPU is about 30-40% used). While the reported frame rate is actually lower in this case, why is my frame rate suffering if my CPU isn't even maxed out?

Does anyone have any idea where this poor performance comes from? Is it immaturity of the platform or some inherent limitation? Is JavaFX a poor basis for a (simple 2D) games platform and is there no other solution than to drop down to C++ with OpenGL acceleration?

Answer 1

No reason that JavaFX would cause the issue you are describing.

It sounds very much like you have mismatched graphics cards, is this the case?