Hello all - I am working on an application that is using Choreographer and OpenGL to render flash patterns on the display. Our GL calls are quite simple, simply toggling the display back and forth between white and black using glClearColor() based on the frame time and status of the pattern we want to apply. The timing of this pattern if very critical, and I am having severe issues getting consistent behavior out of the timing pulses we received from Choreographer to do the rendering.
For simplicity sake, I have basically copied the Basic Dream application in AOSP, so 95% of my code looks exactly like this sample: https://android.googlesource.com/platform/packages/screensavers/Basic/+/master Our only change is that, where they call mSquare.draw() inside of doFrame(), we have another method called drawFrame() that does the following: private void drawFrame() { final boolean nextBit = mPattern[mIndex]; if (nextBit) { glClearColor(1.0f, 1.0f, 1.0f, 1.0f); } else { glClearColor(0.0f, 0.0f, 0.0f, 1.0f); } glClear(GL_COLOR_BUFFER_BIT); return true; } However, for the purposes of this discussion, you can see the *exact same behavior* by simply running the AOSP sample as an application (i.e. changing the Colors class from a DreamService to a launcher Activity). The problem is that on a regular basis (at least once per second, often many times), the debug logging returns that the frame callback took 33ms (instead of 16ms), and in many cases 50ms+! I can understand skipping a rare frame here or there, but skipping 3-4 frames at once seems like I'm missing something big here. Not all devices do this, but high-end devices like the Nexus 5 and GS4 do. Devices we've tested like the Note 3, GS3, and Moto X don't seem to do so nearly as often. Example typical logcat over a period of 30 seconds: 04-11 11:35:43.918 10441-10455/com.android.dreams.basicgl V/ColorsGLRenderer﹕ JANK! (49865722 ms) frame 2 04-11 11:35:43.948 10441-10455/com.android.dreams.basicgl V/ColorsGLRenderer﹕ JANK! (33264161 ms) frame 3 04-11 11:35:43.988 10441-10455/com.android.dreams.basicgl V/ColorsGLRenderer﹕ JANK! (33233641 ms) frame 4 04-11 11:35:44.018 10441-10455/com.android.dreams.basicgl V/ColorsGLRenderer﹕ JANK! (33233644 ms) frame 5 04-11 11:35:45.860 10441-10455/com.android.dreams.basicgl V/ColorsGLRenderer﹕ JANK! (33264161 ms) frame 115 04-11 11:35:46.881 10441-10455/com.android.dreams.basicgl V/ColorsGLRenderer﹕ JANK! (33233641 ms) frame 175 04-11 11:35:47.692 10441-10455/com.android.dreams.basicgl V/ColorsGLRenderer﹕ JANK! (33233642 ms) frame 222 04-11 11:35:48.242 10441-10455/com.android.dreams.basicgl V/ColorsGLRenderer﹕ JANK! (33264160 ms) frame 255 04-11 11:35:49.373 10441-10455/com.android.dreams.basicgl V/ColorsGLRenderer﹕ JANK! (33233643 ms) frame 322 04-11 11:35:53.908 10441-10455/com.android.dreams.basicgl V/ColorsGLRenderer﹕ JANK! (33268229 ms) frame 594 04-11 11:35:56.190 10441-10455/com.android.dreams.basicgl V/ColorsGLRenderer﹕ JANK! (33264161 ms) frame 730 04-11 11:35:56.690 10441-10455/com.android.dreams.basicgl V/ColorsGLRenderer﹕ JANK! (33233643 ms) frame 759 04-11 11:35:57.751 10441-10455/com.android.dreams.basicgl V/ColorsGLRenderer﹕ JANK! (49965416 ms) frame 821 04-11 11:35:57.781 10441-10455/com.android.dreams.basicgl V/ColorsGLRenderer﹕ JANK! (33164467 ms) frame 822 04-11 11:35:58.952 10441-10455/com.android.dreams.basicgl V/ColorsGLRenderer﹕ JANK! (33233643 ms) frame 891 04-11 11:36:04.678 10441-10455/com.android.dreams.basicgl V/ColorsGLRenderer﹕ JANK! (33264161 ms) frame 1235 04-11 11:36:05.919 10441-10455/com.android.dreams.basicgl V/ColorsGLRenderer﹕ JANK! (33264159 ms) frame 1308 04-11 11:36:07.781 10441-10455/com.android.dreams.basicgl V/ColorsGLRenderer﹕ JANK! (33298746 ms) frame 1419 04-11 11:36:07.821 10441-10455/com.android.dreams.basicgl V/ColorsGLRenderer﹕ JANK! (49800618 ms) frame 1420 04-11 11:36:08.672 10441-10455/com.android.dreams.basicgl V/ColorsGLRenderer﹕ JANK! (33325196 ms) frame 1470 04-11 11:36:11.955 10441-10455/com.android.dreams.basicgl V/ColorsGLRenderer﹕ JANK! (33264160 ms) frame 1666 04-11 11:36:13.687 10441-10455/com.android.dreams.basicgl V/ColorsGLRenderer﹕ JANK! (33264159 ms) frame 1770 Any help from the OpenGL experts in the room is greatly appreciated! Is there something the sample is doing poorly that I just unknowingly copied into my own code? -- You received this message because you are subscribed to the Google Groups "Android Developers" group. To post to this group, send email to android-developers@googlegroups.com To unsubscribe from this group, send email to android-developers+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/android-developers?hl=en --- You received this message because you are subscribed to the Google Groups "Android Developers" group. To unsubscribe from this group and stop receiving emails from it, send an email to android-developers+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
