smills - Developer IT

Why does my performance increase when touching the screen?

- by Smills

For some reason my FPS jumps up considerably when I move my mouse around on the screen (on the emulator) while holding the left mouse button. Normally my game is very laggy, but if I touch the screen (and as long as I am moving the mouse around while touching) it goes perfectly smooth. I have tried sleeping for 20ms in the onTouchEvent, but it doesn't appear to make any difference. Here is the code I use in my onTouchEvent: // events when touching the screen public boolean onTouchEvent(MotionEvent event) { int eventaction = event.getAction(); touchX=event.getX(); touchY=event.getY(); switch (eventaction) { case MotionEvent.ACTION_DOWN: { touch=true; } break; case MotionEvent.ACTION_MOVE: { } break; case MotionEvent.ACTION_UP: { touch=false; } break; } /*try { AscentThread.sleep(20); } catch (InterruptedException e) { // TODO Auto-generated catch block e.printStackTrace(); }*/ return true; } In the logcat log, FPS is the current fps (average of the last 20 frames), touch is whether or not the screen is being touched (from onTouchEvent). What on earth is going on? Has anyone else had this odd behaviour before? Logcat log: 12-21 19:43:26.154: INFO/myActivity(786): FPS: 31.686569159606414 Touch: false 12-21 19:43:27.624: INFO/myActivity(786): FPS: 19.46310293212206 Touch: false 12-21 19:43:29.104: INFO/myActivity(786): FPS: 18.801202175690467 Touch: false 12-21 19:43:30.514: INFO/myActivity(786): FPS: 21.118295877408478 Touch: false 12-21 19:43:31.985: INFO/myActivity(786): FPS: 19.117397812958878 Touch: false 12-21 19:43:33.534: INFO/myActivity(786): FPS: 15.572571858239263 Touch: false 12-21 19:43:34.934: INFO/myActivity(786): FPS: 20.584119901503506 Touch: false 12-21 19:43:36.404: INFO/myActivity(786): FPS: 18.888025905454207 Touch: false 12-21 19:43:37.814: INFO/myActivity(786): FPS: 22.35722329083629 Touch: false 12-21 19:43:39.353: INFO/myActivity(786): FPS: 15.73604859775362 Touch: false 12-21 19:43:40.763: INFO/myActivity(786): FPS: 20.912449882754633 Touch: false 12-21 19:43:42.233: INFO/myActivity(786): FPS: 18.785278388997718 Touch: false 12-21 19:43:43.634: INFO/myActivity(786): FPS: 20.1357397209596 Touch: false 12-21 19:43:45.043: INFO/myActivity(786): FPS: 21.961138432007957 Touch: false 12-21 19:43:46.453: INFO/myActivity(786): FPS: 22.167196852834273 Touch: false 12-21 19:43:47.854: INFO/myActivity(786): FPS: 22.207318228024274 Touch: false 12-21 19:43:49.264: INFO/myActivity(786): FPS: 22.36980559230175 Touch: false 12-21 19:43:50.604: INFO/myActivity(786): FPS: 23.587638823252547 Touch: false 12-21 19:43:52.073: INFO/myActivity(786): FPS: 19.233902040593076 Touch: false 12-21 19:43:53.624: INFO/myActivity(786): FPS: 15.542190150440987 Touch: false 12-21 19:43:55.034: INFO/myActivity(786): FPS: 20.82290063974675 Touch: false 12-21 19:43:56.436: INFO/myActivity(786): FPS: 21.975282007207717 Touch: false 12-21 19:43:57.914: INFO/myActivity(786): FPS: 18.786927284103687 Touch: false 12-21 19:43:59.393: INFO/myActivity(786): FPS: 18.96879004217992 Touch: false 12-21 19:44:00.625: INFO/myActivity(786): FPS: 28.367566618064878 Touch: false 12-21 19:44:02.113: INFO/myActivity(786): FPS: 19.04441528684418 Touch: false 12-21 19:44:03.585: INFO/myActivity(786): FPS: 18.807837511809065 Touch: false 12-21 19:44:04.993: INFO/myActivity(786): FPS: 21.134330284993418 Touch: false 12-21 19:44:06.275: INFO/myActivity(786): FPS: 27.209688764079907 Touch: false 12-21 19:44:07.753: INFO/myActivity(786): FPS: 19.055894653261653 Touch: false 12-21 19:44:09.163: INFO/myActivity(786): FPS: 22.05422794901088 Touch: false 12-21 19:44:10.644: INFO/myActivity(786): FPS: 18.6956805300596 Touch: false 12-21 19:44:12.124: INFO/myActivity(786): FPS: 17.434180581311054 Touch: false 12-21 19:44:13.594: INFO/myActivity(786): FPS: 18.71932038510891 Touch: false 12-21 19:44:14.504: INFO/myActivity(786): FPS: 40.94571503868066 Touch: true 12-21 19:44:14.924: INFO/myActivity(786): FPS: 57.061200121138576 Touch: true 12-21 19:44:15.364: INFO/myActivity(786): FPS: 62.54377946377936 Touch: true 12-21 19:44:15.764: INFO/myActivity(786): FPS: 64.05005071818726 Touch: true 12-21 19:44:16.384: INFO/myActivity(786): FPS: 50.912951172948155 Touch: true 12-21 19:44:16.874: INFO/myActivity(786): FPS: 55.31242053078078 Touch: true 12-21 19:44:17.364: INFO/myActivity(786): FPS: 59.31625410615102 Touch: true 12-21 19:44:18.413: INFO/myActivity(786): FPS: 36.63504170925923 Touch: false 12-21 19:44:19.885: INFO/myActivity(786): FPS: 18.099130467755923 Touch: false 12-21 19:44:21.363: INFO/myActivity(786): FPS: 18.458978222946566 Touch: false 12-21 19:44:22.683: INFO/myActivity(786): FPS: 25.582179409330823 Touch: true 12-21 19:44:23.044: INFO/myActivity(786): FPS: 60.99865521942455 Touch: true 12-21 19:44:23.403: INFO/myActivity(786): FPS: 74.17873975470984 Touch: true 12-21 19:44:23.763: INFO/myActivity(786): FPS: 64.25663040460714 Touch: true 12-21 19:44:24.113: INFO/myActivity(786): FPS: 62.47483457826921 Touch: true 12-21 19:44:24.473: INFO/myActivity(786): FPS: 65.27969529547072 Touch: true 12-21 19:44:24.825: INFO/myActivity(786): FPS: 67.84743115273311 Touch: true 12-21 19:44:25.173: INFO/myActivity(786): FPS: 73.50854551357706 Touch: true 12-21 19:44:25.523: INFO/myActivity(786): FPS: 70.46432534585368 Touch: true 12-21 19:44:25.873: INFO/myActivity(786): FPS: 69.04076953445896 Touch: true

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Weird stuttering issues not related to GC.

- by Smills

I am getting some odd stuttering issues with my game even though my FPS never seems to drop below 30. About every 5 seconds my game stutters. I was originally getting stuttering every 1-2 seconds due to my garbage collection issues, but I have sorted those and will often go 15-20 seconds without a garbage collection. Despite this, my game still stutters periodically even when there is no GC listed in logcat anywhere near the stutter. Even when I take out most of my code and simply make my "physics" code the below code I get this weird slowdown issue. I feel that I am missing something or overlooking something. Shouldn't that "elapsed" code that I put in stop any variance in the speed of the main character related to changes in FPS? Any input/theories would be awesome. Physics: private void updatePhysics() { //get current time long now = System.currentTimeMillis(); //added this to see if I could speed it up, it made no difference Thread myThread = Thread.currentThread(); myThread.setPriority(Thread.MAX_PRIORITY); //work out elapsed time since last frame in seconds double elapsed = (now - mLastTime2) / 1000.0; mLastTime2 = now; //measures FPS and displays in logcat once every 30 frames fps+=1/elapsed; fpscount+=1; if (fpscount==30) { fps=fps/fpscount; Log.i("myActivity","FPS: "+fps+" Touch: "+touch); fpscount=0; } //this should make the main character (theoretically) move upwards at a steady pace mY-=100*elapsed; //increase amount I translate the draw to = main characters Y //location if the main character goes upwards if (mY<=viewY) { viewY=mY; } }

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Simple question about the lunarlander example.

- by Smills

I am basing my game off the lunarlander example. This is the run loop I am using (very similar to what is used in lunarlander). I am getting considerable performance issues associated with my drawing, even if I draw almost nothing. I noticed the below method. Why is the canvas being created and set to null each cycle? @Override public void run() { while (mRun) { Canvas c = null; try { c = mSurfaceHolder.lockCanvas();//null synchronized (mSurfaceHolder) { updatePhysics(); doDraw(c); } } finally { // do this in a finally so that if an exception is thrown // during the above, we don't leave the Surface in an // inconsistent state if (c != null) { mSurfaceHolder.unlockCanvasAndPost(c); } } } } Most of the times I have read anything about canvases it is more along the lines of: mField = new Bitmap(...dimensions...); Canvas c = new Canvas(mField); My question is: why is Google's example done that way (null canvas), what are the benefits of this, and is there a faster way to do it?

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