UIKit autorotation for EAGLView « cocos2d for iPhone

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UIKit autorotation for EAGLView

(9 posts) (4 voices)

Started 1 year ago by jpswensen
Latest reply from Dan

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jpswensen
Member

I currently have a game where I am switching from UIScrollView+UIImageView to using Cocos2d with image textures. The problem seems to be that when using UIKit to autorotate the EAGLView, things get messed up. I have included links to two images of the app. One when not rotated and one when rotated. Because the EAGLView doesn't get created until the first time gameplay begins, things work great for the initial orientation whether it be portrait or landscape. However, after rotating things are always messed up.

Initial view
http://imgur.com/TIQN0

Rotated view
http://imgur.com/Pugno

After asking around a lot, I tried to do things like layoutSubviews, reshapeProjection, swapBuffers, etc. but can't seem to solve the problem. Has anyone seen this before and is there a solutions? Note that I don't see the problem in the simulator and my only device is a 2nd gen iTouch.

Posted 1 year ago #
jpswensen
Member

This is kindof a bump, but I wanted to go back and see if the problem somehow had to do with the way I was using cocos2d. To try and simplify things, I went back to the basic template that comes with cocos2d 0.99.5. I changed the default autorotate to UIKit and modified shouldAutorotateToInterfaceOrientation for the RootViewController to always return yes. The following two images show the unrotated view (portrait) and the rotated view (landscape).

Starting with portrait
http://imgur.com/rKyzH

Rotating the device to landscape
http://imgur.com/UoqEZ

Posted 1 year ago #
TBBle
Moderator

Maybe it's your device? I've never seen that on any device I've tested with using the UIKIt autorotation. I have access to all the generations, but I don't recall which ones I've tested the autorotation with...

Posted 1 year ago #
jpswensen
Member

The strange thing is that if I go back and use one of the reference EAGLView implementations from Apple documentation (the one I tested with was PVRTextureLoader), I don't see the same problem. So it must be something different with how the Cocos2d EAGLView and the reference EAGLView work. I tried digging through both of them (with some direction from the folks at freenet #iphonedev) and it seems that one of the big differences is that in layoutSubview for the reference EAGLView they actually destroy the frame buffer and recreate it. I can't see that happening anywhere in all of the cocos2d code.

Disclaimer: I am not an OpenGL expert by any stretch of anyone's imagination.

Posted 1 year ago #
TBBle
Moderator

Yeah, cocos2d just changes the frame dimensions of the EAGLView when it autorotates, I think. (I haven't the code in front of me, but I was looking at it earlier tonight). I don't recall though how the EAGLView in cocos2d responds to that change.

That would account for the effect you're seeing, if the framebuffer is being rendered out into landscape, but still being written to in portrait dimensions.

eg.

Draw calls write:
Ab
Cd
Ef

Which linearly is

EfCdAb (Framebuffer is bottom-first, as I recall)

Scanout puts on screen:
dAb
EfC

(Pretend the capitals have the FPS display, and lower case is black, you'll see what I mean in your latter screenshot pair)

Next chance I get, I might grab an iPod Touch 2nd generation and try it for myself.

Posted 1 year ago #
jpswensen
Member

I really appreciate you taking a look at this. I have tried digging through the cocos2d sources, but I suffer from the fact that I am both not familiar with the underlying codebase and that I don't have any expertise with OpenGL (I can create a cube and texture it with the most basic OpenGL setup copied from elsewhere, but that doesn't even qualify me as a dabbler).

Posted 1 year ago #

Maybe this a completely naive solution (and very well could cause serious OpenGL problems that I don't know about), but I found a solution. The solution was to add the following method to ES1Renderer (and a helper function in EAGLView to call it).

- (void) regenerateBuffers
{
	// Tear down GL
    if(defaultFramebuffer_)
    {
        glDeleteFramebuffersOES(1, &defaultFramebuffer_);
        defaultFramebuffer_ = 0;
    }

    if(colorRenderbuffer_)
    {
        glDeleteRenderbuffersOES(1, &colorRenderbuffer_);
        colorRenderbuffer_ = 0;
    }

	// Create default framebuffer object. The backing will be allocated for the current layer in -resizeFromLayer
	glGenFramebuffersOES(1, &defaultFramebuffer_);
	NSAssert( defaultFramebuffer_, @"Can't create default frame buffer");
	glGenRenderbuffersOES(1, &colorRenderbuffer_);
	NSAssert( colorRenderbuffer_, @"Can't create default render buffer");

	glBindFramebufferOES(GL_FRAMEBUFFER_OES, defaultFramebuffer_);
	glBindRenderbufferOES(GL_RENDERBUFFER_OES, colorRenderbuffer_);
	glFramebufferRenderbufferOES(GL_FRAMEBUFFER_OES, GL_COLOR_ATTACHMENT0_OES, GL_RENDERBUFFER_OES, colorRenderbuffer_);

}

This was per the suggestion on the freenode #iphonedev channel about recreating the frame buffers. Is this an OK solution?

Posted 1 year ago #

neuroscript
Member

I started a similar thread (http://www.cocos2d-iphone.org/forum/topic/12925?replies=3#post-73166) before having this one pointed out.

@jpswensen...any thoughts on how I might try your approach w/o the use of ES1Renderer? I have an app delegate with a view controller whose view is the open gl view (EAGLView). In other words, only the game part of my app is using cocos, while the rest is using typical apple technology.

Posted 1 year ago #
Dan
Member

Hello sorry to bump an old thread but I found out that this problem existed after uploading my binary. Im using .99.5 and using kGameAutorotationUIViewController. This problem only seems to be on iTouches. Besides what jpswensen mentioned, was there some type of "official" fix for this?

In another strange note - changing the autorotation to kGameAutorotationCCDirector instead of kGameAutorotationUIViewController causes my application to run ~20fps higher in landscape mode. So before a particular scene would run at 60fps when in portrait and 40fps while in landscape and now it runs 60fps landscape also (this happens regardless of hardware version).

Posted 1 year ago #

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