iPhone memory usage increases when pushing an EAGL-View using UINavigationController - ios

Question

I am working on a simple iOS game and I am having a problem with UINavigationController and an EAGL-View.
The situation is as follows: I use one EAGL-View in conjunction with multiple controllers.
Whenever I push the MainViewController (which does all the custom openGL drawing), I end up using more memory (around 5MB per push!).
The problem seems to be within [eaglView_ setFramebuffer] - or at least that's where almost all allocations seem to happen (I've checked the live bytes via Instruments - around 70% of memory is allocated in this function).
EAGLView::setFramebuffer:
- (void)setFramebuffer {
if (context) {
[EAGLContext setCurrentContext:context];
if (!defaultFramebuffer)
[self createFramebuffer];
glBindFramebuffer(GL_FRAMEBUFFER, defaultFramebuffer);
glBindFramebuffer(GL_FRAMEBUFFER, msaaFramebuffer);
glViewport(0, 0, framebufferWidth, framebufferHeight);
}
}
and EAGLView::createFramebuffer:
- (void)createFramebuffer
{
if (context && !defaultFramebuffer) {
[EAGLContext setCurrentContext:context];
// Create default framebuffer object.
glGenFramebuffers(1, &defaultFramebuffer);
glBindFramebuffer(GL_FRAMEBUFFER, defaultFramebuffer);
// Create color render buffer and allocate backing store.
glGenRenderbuffers(1, &colorRenderbuffer);
glBindRenderbuffer(GL_RENDERBUFFER, colorRenderbuffer);
[context renderbufferStorage:GL_RENDERBUFFER fromDrawable:(CAEAGLLayer *)self.layer];
glGetRenderbufferParameteriv(GL_RENDERBUFFER, GL_RENDERBUFFER_WIDTH, &framebufferWidth);
glGetRenderbufferParameteriv(GL_RENDERBUFFER, GL_RENDERBUFFER_HEIGHT, &framebufferHeight);
glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_RENDERBUFFER, colorRenderbuffer);
//MSAA stuff
glGenFramebuffers(1, &msaaFramebuffer);
glGenRenderbuffers(1, &msaaRenderBuffer);
glBindFramebuffer(GL_FRAMEBUFFER, msaaFramebuffer);
glBindRenderbuffer(GL_RENDERBUFFER, msaaRenderBuffer);
glRenderbufferStorageMultisampleAPPLE(GL_RENDERBUFFER, 4, GL_RGBA8_OES, framebufferWidth, framebufferHeight);
glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_RENDERBUFFER, msaaRenderBuffer);
glGenRenderbuffers(1, &msaaDepthBuffer);
glBindRenderbuffer(GL_RENDERBUFFER, msaaDepthBuffer);
glRenderbufferStorageMultisampleAPPLE(GL_RENDERBUFFER, 4, GL_DEPTH_COMPONENT16, framebufferWidth, framebufferHeight);
glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_RENDERBUFFER, msaaDepthBuffer);
if (glCheckFramebufferStatus(GL_FRAMEBUFFER) != GL_FRAMEBUFFER_COMPLETE)
NSLog(#"Failed to make complete framebuffer object %x", glCheckFramebufferStatus(GL_FRAMEBUFFER));
}
}
As you can see - nothing special there.
I switch my ViewControllers like this: (in the AppDelegate)
- (void) swichToViewController: (UIViewController*) newViewController overlapCurrentView: (bool) overlap {
// get the viewController on top of the stack - popViewController doesn't do anything if it's the rootViewController.
if(!overlap) {
// clear everything that was on the eaglView before
[eaglView_ clearFramebuffer];
[eaglView_ applyMSAA];
[eaglView_ presentFramebuffer];
}
UIViewController* oldViewController = [navController_ topViewController];
// see if the view to be switched to is already the top controller:
if(oldViewController == newViewController)
return;
// if the view is already on the stack, just remove all views on top of it:
if([[navController_ viewControllers] containsObject:newViewController]) {
[oldViewController setView:nil];
[newViewController setView:eaglView_];
[navController_ popToViewController:newViewController animated:!overlap];
return;
}
// else push the new controller
[navController_ popViewControllerAnimated:NO];
[oldViewController setView:nil];
[newViewController setView:eaglView_];
[navController_ pushViewController:newViewController animated:!overlap];
}
Finally, I render my sprites like this: (In my MainViewController.mm):
- (void)drawFrame
{
// When I delete this line, I just get a white screen, even if I have called setFramebuffer earlier(?!)
[(EAGLView *)self.view setFramebuffer];
glClearColor(1, 1, 1, 1);
glClear(GL_COLOR_BUFFER_BIT);
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
GLfloat screenWidth = [UIScreen mainScreen].bounds.size.width;
GLfloat screenHeight = [UIScreen mainScreen].bounds.size.height;
glOrthof(0, screenWidth, 0, screenHeight, -1.0, 1.0);
glViewport(0, 0, screenWidth, screenHeight);
[gameManager_ playGame];
//MSAA stuff
[(EAGLView *)self.view applyMSAA];
[(EAGLView *)self.view presentFramebuffer];
[(EAGLView *)self.view clearFramebuffer];
}
Something that might be worth mentioning is that I don't allocate the views every time I push them, I keep references to them until the game exits.
[gameManager_ playGame] draws the sprites to the screen - but I've used this method in another project without any memory problems.
Any help would be really appreciated as I've been stuck on this for 2 days :/
Edit:
I've been able to narrow the problem down to a call to gldLoadFramebuffer. This is called whenever I try to draw something on the screen using an openGL function.
It seems to consume more memory when the context changes... But how could I avoid that?

Answer 1

I think I found the problem.
For anyone interested: The MSAA-Buffers weren't correctly deleted on switching the views. That caused the performance to drop significantly after a few pushes, and was also responsible for the increase in memory usage.