Gomobile multisampling

dskinner · October 5, 2015, 4:26pm

As far as I understand, es2 left multisampling up to the vendor. It looks like on android, this is just a matter of choosing an appropriate egl context. On iOS, things look a bit more involved.

Am I correct to assume there’s no turn-on-multisampling switch?

rakyll · October 5, 2015, 5:49pm

As far as I know (fairly unknowledgeable about Open GL ES2), on Android it is possible to turn it on with a particular EG config spec. But not every device provides support, so you need to fallback to a config that has multisampling turned off.

Apple provides the glRenderBufferStorageMultisampleAPPLE extension which I haven’t taken a closer look.

dskinner · October 5, 2015, 6:02pm

I had noticed bindings for glSampleCoverage, and also not particularly knowledgeable about es2, but wanted to check and make sure there wasn’t an easy switch to flip on for an early demo. Thanks, sounds like I’d have to handle antialiasing manually.

rakyll · October 5, 2015, 6:07pm

@crawshaw is the person you need for guidance. (I didn’t know that he was already on the forum.)

crawshaw · October 5, 2015, 9:06pm

There’s no exposed setting for this right now, to get multisampling on Android it’s a matter of passing EGL_SAMPLE_BUFFERS into the EGL configuration here:

github.com

golang/mobile/blob/master/app/android.c#L116


	activity->callbacks->onNativeWindowDestroyed = onNativeWindowDestroyed;
	activity->callbacks->onInputQueueCreated = onInputQueueCreated;
	activity->callbacks->onInputQueueDestroyed = onInputQueueDestroyed;
	activity->callbacks->onConfigurationChanged = onConfigurationChanged;
	activity->callbacks->onLowMemory = onLowMemory;


	onCreate(activity);
}


// TODO(crawshaw): Test configuration on more devices.
const EGLint RGB_888[] = {
	EGL_RENDERABLE_TYPE, EGL_OPENGL_ES2_BIT,
	EGL_SURFACE_TYPE, EGL_WINDOW_BIT,
	EGL_BLUE_SIZE, 8,
	EGL_GREEN_SIZE, 8,
	EGL_RED_SIZE, 8,
	EGL_DEPTH_SIZE, 16,
	EGL_CONFIG_CAVEAT, EGL_NONE,
	EGL_NONE
};

I have some idle thoughts about an app.Options, but I haven’t explored it.

I suspect the only values of EGL_SAMPLE_BUFFERS that’s portable and possible to support is 0 and 1.

system · January 3, 2016, 9:06pm

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