So ive been doing some iphone development with some OpenglES in it, but i am getting a rather weird error when i call prepareToDraw on my effect. My program in short simulates dice rolling (trying to learn objective-c and opengl). The program works fine for the most part, i can use everything ive programmed my app to do (with its bugs in the physics but ill fix that later). The problem comes in after ive used the part that contains the OpenGL.
The program contains 2 menu's you have to go through in order to reach the screen that is using OpenGL, once you have used the apps OpenGL part and go back to the previous menu, then try go back to the OpenGL part again, i get a print out saying GL ERROR: 0x0501. ive narrowed it down to be caused by the prepareToDraw method from my effect. The other weird part about it, is if i go back, then forward again, the OpenGL works again, and can be repeated again and again for it to be working and breaking every second time you go into the OpenGL part.
I've been searching around for similar problems to mine, but each time its got something to do with loading textures that are not a power-of-two texture, which doesnt help me because im not even using textures yet, just colored vertices.
ive pastebin'd my two code files where the problem should lie
Dice.m: http://pastebin.com/ze1DEEzs
in the draw method you'll see my printouts have narrowed down where the problem lies, which is the prepareToDraw method. (line 308)
RollViewController.m: http://pastebin.com/VycwAh3R
this file is where i setup the effect and the context etc, so i must be doing something wrong in here to cause the prepareToDraw method to mess up every 2nd time i run the OpenGL part of the program. i have a feeling it has something to do with not letting go some kind of resource to do with the context and the effect, but i cant find anything about deleting context and effect (probably because you dont need to but im not sure).
I hope there is someone out there that has run into the same problem and can answer my question and i hope its not just a silly mistake because ive been trying to solve this for a while now :)
thanks
After much pain and suffering i finally found a fix to the problem. Im not exactly sure why this is a problem, but creating the context within the OpenGL part (aka RollViewController.m) is not the way to do it. Instead you should create it once throughout the lifetime of your program and just set your current context for your glkview to be the context you have made. Maybe someone can enlighten me why recreating the context is a bad idea.
In my code i have a profile object that gets passed around between views and menu's so that they can all communicate with the same data, so i just defined a public context within my profile object so that everything can get access to the context instead of creating their own (and breaking).
The error seems general and might be because of different issues. I avoided it(for now) by not using mipmaps. I commented the following code I had and don't have the error anymore.
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER,GL_LINEAR_MIPMAP_NEAREST);
glGenerateMipmap(GL_TEXTURE_2D)
Related
I’ve encountered a strange problem during iOS AUv3 Instrument development which I’m having trouble finding information on. I’ve spent a couple weeks now attempting to debug this, and I was wondering if anyone else has encountered it. It feels more like an "OS killed the app" than a crash, so I use the term crash loosely. Here are the symptoms:
It doesn't seem to ever happen on initial instantiation; it's when a project is reloaded. But, you can comment out setFullState and it'll still occur.
The “crash” is inconsistent. Like a lot of slippery bugs, it’ll start happening consistently and then it’ll stop happening completely.
When it does happen, it initially appears to load fine: the view loads and looks correct, and it produces audio. But, after a couple seconds, the plugin view disappears and it stops producing audio. I see this in the console log:
viewServiceDidTerminateWithError:: Error Domain=_UIViewServiceInterfaceErrorDomain Code=3 "(null)" UserInfo={Message=Service Connection Interrupted}
You don’t have to generate any MIDI events to crash it. It would crash even after I commented out the processing block.
If anyone has any ideas, including how to get some useful debugging info out of this situation, let me know!
I tried to look at crash logs, but there are no crash logs generated
didReceiveMemoryWarning is not tripped. In fact, I did an experiment where I allocated 100 megs and memset’d it on startup, and it didn’t crash it.
I tried attaching a debugger, but it goes from “no debug session” to “waiting to attach” after it crashes-- at no point does it actually attach. It will attach if I then reload the plugin, but then it won’t crash. The Zombies and Leaks tools didn't reveal anything, nor did the memory sanitizers.
Using a Storyboard instead of a XIB didn't change the behavior (not sure why it would, but it was one of the last few differences between this and Apple's example).
I created a very tiny example project which exhibits the problem (unfortunately, I cannot post any code which shows the problem because I cannot find where exactly the problem code is-- maybe it's even a project setting?). It has a minimal GUI, no setFullState, and generates white noise:
https://drive.google.com/open?id=1dw3xTHn3qY411eXLaIb_9_S5PAtrr5Nk
Expected: It doesn't crash or disappear randomly
Actual results: After reloading a project file which uses this AUv3, the plugin will disappear after a few seconds. It initially produces audio normally and the GUI looks OK, but then vanishes.
I would like to start off by mentioning that I am very new to coding, so some things that might seem very simple to someone with intermediate experience will probably not click quite as fast with me.
Okay so with the code I am writing, I am trying to get a three.js cube object to move to the places I click, using tweening. I managed to get this to work, but when I try to create a frame using three.js lines, the code stops working. In detail: when I add
line = new THREE.Line( lineGeometry, new THREE.LineBasicMaterial() );
scene.addObject( line );
to the Init() function. What is cause of this? My guess is it has something to do with global/local variables but even if that were correct I have no idea how to fix it !
This is the jsfiddle for reference
I'm using matplotlib housed in a wxPython panel to do some heavy duty plotting. My issues comes when using native panning tool - it's appears as though matplotlib tries to constantly redraw the canvas as you drag the pan handle around. With the amount of data I'm plotting this is getting really choppy (already optimized with Collections for data etc)
In terms of performance I think it would be much preferable for the canvas to just draw once when the mouse is released at the end of a pan. I realise this will mean I have to extend the WxAgg NavigationToolbar2 class with my own, but I'm wondering if anyone has attempted something similar to this and can advise me on which functions to override?
many thanks
I've spent a lot of time making modification on the matplotlib backends, I've never done this specific change, but I can show you one line of code to comment out that will stop the dynamic updating:
I presume you are using the WxAgg backend, if this is the case, open this file: C:\Python27\Lib\site-packages\matplotlib\backends\backend_wx.py
And comment out the line indicated here:
def dynamic_update(self):
d = self._idle
self._idle = False
if d:
#self.canvas.draw() #<--- Comment out to stop the redrawing during the Pan/Zoom
self._idle = True
I tested this and it seems to nicely solve your issue. I did some quick digging and I didn't see any other functions calling this procedure so you might even be able to just change it to:
def dynamic_update(self):
pass
...Which is the same code you'll find in the base NavigationToolbar2 class
(And of course, if you're happy with this change you can do a little more work to make your own custom backend with this kind of modification. Just to make sure you don't lose the change when upgrading matplotlib)
I am working on trying to make a splitview based application. I am trying to use Apple's MultipleDetailView example code
http://developer.apple.com/library/ios/#samplecode/MultipleDetailViews/Introduction/Intro.html
I have never really used example code like this (I usually just atart from scratch). All i did was copy the code into the correct classes of my app, but when I try to run it on the simulator the app doesn't open.
I feel like I am maybe forgetting something obvious, since I didn't code it myself.
Thanks!
The usual debugging technique applies. Put a breakpoint somewhere early in the program -- the first line of main() for instance, and debug from there. Do you hit the breakpoint? If yes, move forward through the code until you find the line that causes the problem. If no, try to back up even further if you can, and also look for any clues as to what's going wrong. If the app is running at all, there should be some sort of error message in the console output.
"...the app doesn't open" doesn't tell us nearly enough to help you. Something like "the app delegate is instantiated, but it's window and splitViewController properties are nil" goes much further toward getting to the root of the problem.
I want to create a new object so as to instantiate and use it several times;
For example, if I want to create an object that has a label and a button inside, how do I? I created a new NSObject but inside it has nothing, then how do I make everything from scratch since there was a viewDidLoad for example (obviously, since it has a view)?
thanks!
Your questions lead me to think that you're really just starting out. There's nothing wrong with that, but rather than trying to summarize several megabytes of documentation in a few paragraphs, I'm just going to point you to the iOS Starting Point. I think that you're just trying to create a container that can hold other UI components? If so, use a UIView for that. However, don't jump in and try to get something specific done without first reading through some of the Getting Started documents -- you'll just end up back here, and we'll just point you back to the docs. You might like the Your First iOS Application guide, as that lets you get your feet wet but explains things along the way.