How to handle startup flicker in landscape?

cocos2d for iPhone » Programming » cocos2d support (graphics engine)

How to handle startup flicker in landscape?

(19 posts) (4 voices)

Started 1 year ago by PJX
Latest reply from CJ

Tags:

No tags yet.

PJX
Member

I use code similar to this on startup to make a smooth transition from the Default.png to my menu:

//Fix flash of black before first scene can load Sprite *sprite = [[Sprite spriteWithFile:@"Default.png"] retain]; sprite.anchorPoint = CGPointZero; [sprite draw]; [[[Director sharedDirector] openGLView] swapBuffers]; [sprite release];

However, how do I add a transform to this for landscape mode? On app startup iPad has two different Default-x.png depending on whether it's portrait or landscape. I can't get the landscape one to display correctly...it's not rotating.
tia, PJ

Posted 1 year ago #

PJX
Member

I came up with the following. Initial tests show it to work, but I'm no OpenGL expert, so please correct any mistakes:

CCSprite *sprite = [CCSprite spriteWithFile:@"Default-Landscape.png"];
//	sprite.anchorPoint = CGPointZero;  // Necessary?
	CC_ENABLE_DEFAULT_GL_STATES();
	glRotatef( 90.0f, 0.0f, 0.0f, 1.0f );
	glTranslatef(0.0f, -768.0f, 0.0f);
	[sprite draw];
	glTranslatef(0.0f, 768.0f, 0.0f);
	glRotatef( -90.0f, 0.0f, 0.0f, 1.0f );
	CC_DISABLE_DEFAULT_GL_STATES();
	[[[CCDirector sharedDirector] openGLView] swapBuffers];
	[[CCTextureCache sharedTextureCache] removeTexture:[sprite texture]];

Do I need to "undo" the glRotate and glTranlate calls? Anything missing that should be there to do this cleanly?
tia, Patrick

Posted 1 year ago #

CJ
Moderator

Please see this thread:
http://www.cocos2d-iphone.org/forum/topic/2055

@PJX your code is probably ok for your situation, but I don't think it will properly handle all rotations (Landscape left and right, portrait upside down).

Please try the code from the other thread and let me know if that is working for you.

Thanks.

Posted 1 year ago #
mickeyl
Member

Dear PJX, we have been discussing this in http://www.cocos2d-iphone.org/forum/topic/2055 -- your solution works fine for me, thanks a lot!!

Posted 1 year ago #

patrickC
Member

Hey PJX, you can also just rotate the sprite rather than using glTranslate and glRotate

CCSprite *sprite = [CCSprite spriteWithFile:@"Default.png"];
//90 for landscape left, -90 for landscape right
[sprite setRotation:-90];
CC_ENABLE_DEFAULT_GL_STATES();
[sprite draw];
CC_DISABLE_DEFAULT_GL_STATES();
[[[CCDirector sharedDirector] openGLView] swapBuffers];

End result is the same, just less confusing to end users.
cheers

Posted 1 year ago #

mickeyl
Member

This only works for LandscapeLeft though... could you think of a way how to make it work depending on the landscape orientation?

Posted 1 year ago #
patrickC
Member
If you're referring to my post, you'll notice there's a commented line that reads:
```
//90 for landscape left, -90 for landscape right
```
Which means you just need to rotate the sprite by 90 instead of -90 if you want landscape left.
Posted 1 year ago #
mickeyl
Member

@patrickC: No, i was referring to PJX, your solution doesn't work, since at this time the coordinate system of Cocos is not yet properly setup for landscape. With your solution I get a rotated image, but half of the screen is a black stripe.

Posted 1 year ago #
patrickC
Member
Well, that's a bit different from what I'm seeing.
Obviously before calling that draw, I rotate to landscape accordingly
```
[[CCDirector sharedDirector] setDeviceOrientation:CCDeviceOrientationLandscapeLeft];
```
If for some reason you're not doing that, then I wouldn't know.
A "brutal" fix could be simply to translate the sprite to the proper position.

Afterall, with the glTranslate and glRotate calls that's exactly what's going on.
Posted 1 year ago #
mickeyl
Member

Hmm, well I can only say that for me [sprite.SetRotation] has no effect whatsoever at this point of the scenery. PJX's code works for me, but only w/ LandscapeRight.

Posted 1 year ago #
mickeyl
Member

In LandscapeLeft I get the picture up-side-down and now I'm fighting with the translate call to get that fixed :)

Posted 1 year ago #
PJX
Member

@mickeyl, yes, I expected the other landscape orientation wouldn't work with those calls. I'm going to mess with that tonight as I prepare my iPad app for final submission and will post what I come up with then.

[sprite setRotation:xx] didn't work for me either.

@CJ, I read the post you referenced. The only new thing I see there is code which does a screen capture and redisplays it. I would think that would handle all rotations, but I couldn't get that to work on the iPad. I'll try messing with that again tonight as well.

Thanks to all who replied!
-Patrick

Posted 1 year ago #
CJ
Moderator

When you are doing the stuff for iPad, are you providing 2 or 4 startup images?

Posted 1 year ago #

PJX
Member

Two. Here is my final code for submission:

// Stop flicker
		CC_ENABLE_DEFAULT_GL_STATES();
		CCSprite *sprite;
		CGSize size = [[CCDirector sharedDirector] winSize];
		switch ([[CCDirector sharedDirector] deviceOrientation]) {
			case CCDeviceOrientationLandscapeLeft:
				sprite = [CCSprite spriteWithFile:@"Default-Landscape.png"];
				sprite.anchorPoint = CGPointZero;
				glTranslatef(0.0f, size.width, 0.0f);
				glRotatef(-90.0f, 0.0f, 0.0f, 1.0f);
				[sprite draw];
				glRotatef(90.0f, 0.0f, 0.0f, 1.0f);
				glTranslatef(0.0f, -size.width, 0.0f);
				break;</p>
			case CCDeviceOrientationLandscapeRight:
				sprite = [CCSprite spriteWithFile:@"Default-Landscape.png"];
				sprite.anchorPoint = CGPointZero;
				glTranslatef(size.height, 0.0f, 0.0f);
				glRotatef(90.0f, 0.0f, 0.0f, 1.0f);
				[sprite draw];
				glRotatef(-90.0f, 0.0f, 0.0f, 1.0f);
				glTranslatef(-size.height, 0.0f, 0.0f);
				break;
			case CCDeviceOrientationPortraitUpsideDown:
				sprite = [CCSprite spriteWithFile:@"Default-Portrait.png"];
				sprite.anchorPoint = CGPointZero;
				glTranslatef(size.width, size.height, 0.0f);
				glRotatef(180.0f, 0.0f, 0.0f, 1.0f);
				[sprite draw];
				glRotatef(-180.0f, 0.0f, 0.0f, 1.0f);
				glTranslatef(-size.width, -size.height, 0.0f);
				break;
			default:
				sprite = [CCSprite spriteWithFile:@"Default-Portrait.png"];
				sprite.anchorPoint = CGPointZero;
				[sprite draw];
				break;
		}
		CC_DISABLE_DEFAULT_GL_STATES();
		[[[CCDirector sharedDirector] openGLView] swapBuffers];
		[[CCTextureCache sharedTextureCache] removeTexture:[sprite texture]];

Jeez I hate this editor lol

Posted 1 year ago #

mickeyl
Member

@PJX: Awesome, thanks a lot! Riq: Can we get that into cocos2d?

Posted 1 year ago #
PJX
Member

Don't jump for joy just yet...my app got rejected because the orientation changes don't work on the device. They work fine in the simulator, but not on the device apparently. The screenshots they sent looked like things were not getting rotated correctly.

For all I know there is something in Cocos itself that is the problem. Without a device, I can't tell. I'm waiting for a 3G version...any of you getting one tomorrow and can play with this?
-PJ

Posted 1 year ago #
CJ
Moderator

Maybe if you tell the director it will be in standard portrait during startup and redisplay the default image unrotated, then on running the first scene update the director's orientation?

Posted 1 year ago #
PJX
Member

Okay, I finally got my 3G device. There was no problem with the code I provided. Howver, I was ignoring the face up and facedown orientation changes and that caused a problem.

Posted 1 year ago #
CJ
Moderator

@PJX can you explain what you do to handle face up/down orientation changes?

Posted 1 year ago #

RSS feed for this topic

Reply

You must log in to post.