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GeeXLab => GeeXLab - english forum => Topic started by: bobtarask on August 31, 2016, 04:01:14 PM

Title: RASPBERRY PI transparent window with transparent PNG overlay (demo_gles2_v2.xml)
Post by: bobtarask on August 31, 2016, 04:01:14 PM
Hello,

We are using geexlab to display partly transparent overlays on the raspberry pi.

We are using the demo demo_gles2_v2.xml  (http://www.geeks3d.com/hacklab/20151207/how-to-control-the-window-opacity-on-the-raspberry-pi/)

It is working with full transparency (alpha = 0) but our PNG image has variable levels of transparency. As an example if a pixel is partly transparent (alpha = 0.5), it will appear on the screen fully opaque (alpha = 1).

Please could you give us some hints what we should modify on the demo to make it work with our transparent image?


Thanks and best regards,

Etienne




Title: Re: RASPBERRY PI transparent window with transparent PNG overlay (demo_gles2_v2.xml)
Post by: JeGX on August 31, 2016, 07:38:13 PM
I played with RPi transparency long time ago  :P

Ok... do you output the right alpha value in the pixel shader? According to what I wrote in the article, if rpi_alpha_flag="0", you should control the opacity with the alpha value generated by the pixel shader.
Title: Re: RASPBERRY PI transparent window with transparent PNG overlay (demo_gles2_v2.xml)
Post by: bobtarask on September 01, 2016, 01:25:51 PM
HELLO putting rpi_alpha_flag="3" solved the problem
Title: Re: RASPBERRY PI transparent window with transparent PNG overlay (demo_gles2_v2.xml)
Post by: JeGX on September 01, 2016, 04:25:53 PM
great!