[meta-freescale] Enabling transparency on overlay surface

Eric Nelson eric.nelson at boundarydevices.com
Fri Nov 7 12:03:27 PST 2014

Hi Jason,

On 11/07/2014 12:11 PM, Jason Anderson wrote:
> HI,
> I am working on an OpenGL ES application and trying to use /dev/fb1 as
> an overlay on my i.MX6 (Boundary Devices BD-SL-i.MX6) .  My current
> image is Yocto 1.6 , 3.10.17 kernel.
> I have my app rendering my background to /dev/fb0 and my overlay to
> /dev/fb1, but I can’t get fb1 transparency enabled.  Does any have have
> an example of how to use the overlay with OpenGL ES/EGL?

The fb1 transparency doesn't have anything to do with OpenGL,
but is available using a set of custom ioctls on the frame-buffer

In particular, look at MXCFB_SET_GBL_ALPHA and MXCFB_SET_CLR_KEY:


The MXCFB_SET_OVERLAY_POS ioctl is also very useful for placing
fb1 on top of fb0.



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