I've just started playing with OpenGL ES, mostly on iPad and have noticed some problems I cannot find the answer to. First I've tried using two EAGLViews using separate renderers in the same window. Basically think the OpenGL ES example project in XCode but with two EAGLViews and two renderers etc. Now this does not seem to work in the simulator, it only shows one of the views (it seems to run the rendering code, but only one view is displayed with openGL) but when run on the device (an iPad using iOS 4.2) it does work, at least kind of which leads to the next question.
The updates to the rendering is triggered using CADisplayLink on both these views. This does however cause some problems. Most of the time, after just a short while, the updates on one of the views stops, its CADisplayLink stops triggering. This only happens on the device and not in simulator. It can be "fixed" by using timers instead of CADisplayLink, or timer on one view and DisplayLink on the other, I would like to know what is causing this though. I'm creating the display link like this (in both views):
self.displayLink = [NSClassFromString(#"CADisplayLink") displayLinkWithTarget:self selector:#selector(drawView:)];
[displayLink setFrameInterval:animationFrameInterval];
[displayLink addToRunLoop:[NSRunLoop currentRunLoop] forMode:NSDefaultRunLoopMode];
Now the last question is about an odd thing I have noticed. When running the OpenGL ES example project provided in Xcode in the iPad simulator with the view resized below 760 in width, it does not render anything to screen, It only concerns the width though, the height can be resized in any way. It only happens in the simulator, not on the device.
So the questions are basically if the things mentioned above are bugs, features or if I'm just doing it wrong?
Thanks
/j0h
I found a similar problem running two OpenGL views at once, each running on a separate CADisplayLink, both running forMode: NSDefaultRunLoopMode. When testing on an iPhone 4S running iOS 5.1, there were no issues except for when exiting the MPMediaPickerController, one of the views would stop rendering. However, on the iPod Touch 3rd gen running iOS 5.0.1, I did notice the issue where one or the other view would stop rendering randomly (due to CADisplayLink not firing). I was able to fix it by switching to NSTimer for both views (just doing it for one or the other wouldn't work). Sizing to multiples of 32 did not make any difference for me.
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I am developping a relatively simple frame based iphone game, and it runs quite smoothly. However, when I switch views and then back again a couple of times everything starts to lagg severely.
Maybe someone recognizes this as a simple programming problem. (e.g. not setting iVars to nil, not switching views correctly, loading too much variables at the same time, etc.)
NOTE: this happens only after having switched views over 10 times.
I am working on an OpenGL application for the iPhone...
My app has only 2 views:
An OpenGL view and, as a subview for the OpenGL view, a view with the sole purpose of catching touch events...
The problem is that after about 10-15 minutes of keeping the app running on the device, I get a big (0.5s-1s) delay between every touchesMoved:withEvent: call
The animation runs smooth, and CPU usage is also not the problem (10% at most)
I have no idea what might be causing this
That is weird, eh.
This happens ON THE DEVICE right? When you are not running tethered from XCode?
I would guess you are using up a lot of memory, either a leak or just in some way using up more and more memory as time goes on.
Are you familiar with the various memory tools to watch what is going on?
Also, what about this: launch a few other large apps that remain in the background. Run your app until the problem exhibits. Then, kill the other apps. Does the problem suddenly go away? If so that would suggest you're low on memory.
Would be interested to hear.
I have implemented CADisplayLink, but yet it behaves similar to NSTimer in that when there are a lot of draws it locks the fps to 40 and never gets out of there, even if there are a lot fewer draws afterward. This happens on the itouch 3 and itouch 4. I'm using openGL to render, and openAL for sounds. What's going on. Help Please!!!
I would start by profiling the app. I wouldn't suspect CADisplayLink weirdness till it's demonstrated that the app should in fact be running faster than it is.
I'm working on an iPhone game using OpenGL ES. I recently updated my iPhone 3G to iOS4, and ever since the update, when I've been play-testing my app I've been getting very high latency on my accelerometer and touch events -- my phone will often respond a second later than it should, which makes the game unplayable. This doesn't occur all the time -- about half the time the game works perfectly. I've set up the accelerometer following Apple's guidelines; one of my view controllers calls [UIAccelerometer sharedAccelerometer] in its init method and implements the appropriate delegate method which just grabs the x-component of the UIAccceleration object, and I have another view connected to a view controller that detects touches using touchesBegan:withEvent: and the other touch event handlers.
I emphasize that this worked fine when I was running 3.1.3. I'm totally stymied. Has anyone run into this problem before? Is this a known bug with the 3G and iOS4? Should I update to CMMotionManager?
I think it's been widely reported that 3G and iOS4 don't play nicely... very sluggish lack of responsiveness over all. You would be wise to do iOS4 testing on an iPhone4 or 3GS.
Touch events shouldn't lag. What you might be experiencing is some form of render lag (not sure how deep the render pipeline, but in many PC games it's noticeable at not-so-low framerates), which feels like input lag.
Apart from that, I dunno. CMMotionManager produces much nicer data, but only works on iPhone 4 IIRC.
I'm using the cocos2d framework for various of my applications, and have run into the following problem. I have set up a few sequences of actions and CallFuncNDs, the actions have durations set up and when I run it in the iPhone simulator, it works just like I expect it to: transitions take the amount of time I set them to and they go in the correct order.
When I test it on my provisioned iPhone, it all plays out in less than one second. Correct order, timing is proportional between actions, but it's all compressed into one second.
Any one have any idea why the cocos2d animations would behave differently on a device? My code is all set up similar to the cocos2d effect demos, with the difference that I am animating a ParticleSystem and not a Sprite - though the problem still shows up with Sprites.
I have experienced similar difficulties where testing the code in the simulator, it runs flawlessly. But when moved over to the device, the timing appears to be off. I've attributed this difference to the Simulator's use of the desktop CPU and Memory, where as the device is utilizing it's physical hardware and the timing is off because of how Cocos2d processes things (frame by frame, in a 'game loop'). When you start doing a couple things, the frame rate drops and Cocos miscues ... especially when you have schedules that run extremely close to each other, or schedules that cancel themself and reschedule with different timings (in increments as low as 0.1 and below is where I've run into this the most).