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I started a new iOS project recently. I'd like to support also Android so I choose SpriteBuilder with newest cocos2d-iphone (cocos2d-swift).

I use CCClippingNode for clipping contents. It needs 24bit depth buffer and 8 bit stencil buffer, so I needed to add the following line to AppDelegate.m to application:didFinishLaunchingWithOptions:

[cocos2dSetup setObject:@GL_DEPTH24_STENCIL8_OES forKey:CCSetupDepthFormat];

naturally this is only for iOS. According to logs it should work for Android without any additional code, as it logs the following lines on startup:

EGL_DEPTH_SIZE = 24
EGL_STENCIL_SIZE = 8

Later when I create CCClippingNode in code, it logs:

[CCClippingNode initWithStencil:]_block_invoke : Stencil buffer is not enabled; enable it by passing GL_DEPTH24_STENCIL8_OES into the depthFormat parrameter when initializing CCGLView. Until then, everything will be drawn without stencil.

It happens because the following line in CCClippingNode.m returns 0:

glGetIntegerv(GL_STENCIL_BITS, &_stencilBits);

On iOS GL_STENCIL_BITS is 8 (after setting CCSetupDepthFormat to GL_DEPTH24_STENCIL8_OES). On Android it's 0.

What should I do to make it work also on Android?

I use SpriteBuilder 1.4.0-beta.3 and Cocos2D-Swift version 3.4.1-develop

Gergely
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1 Answers1

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I found out where was the problem, so I'll answer my own question :)

The whole problem was in misleading logs. We need to modify function setupView: in Platforms/Android/CCGLView.m. CCGLView is logging EGL values before calling eglChooseConfig which sets depth and stencil size to 0.

Moving line

logConfig(_eglDisplay, _eglConfiguration);

after

eglChooseConfig(_eglDisplay, configAttribs, &_eglConfiguration, 1, &numConfigs)

will show the real values. With this modification the following lines will appear in logs:

EGL_DEPTH_SIZE = 0
EGL_STENCIL_SIZE = 0

So we have the real values in the log, all wee need is to set them. This can be done by adding the following two lines to structure configAttribs[] (at the very beginning of function setupView:)

EGL_DEPTH_SIZE, 24,
EGL_STENCIL_SIZE, 8,

And CCClippingNode suddenly starts to clip contents on Android too

NOTE: Only configAttribs[] structure needs to be enhanced by the mentioned two lines. The other changes are needed only when you need the real EGL values in the log for some other reason.

Gergely
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