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Problem with OpenGL image on top of camera preview


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Hello everyone,

I have a problem with my new Galaxy S3 and I hope someone here might help me with that.

I'M trying to make an AR-app. So I have a Camera-Preview and on top of it an OpenGLES SurfaceView.

So I render some objekts on the camera image.

On my old Galaxy S1 and the S2 everything works great.

But now I got a problem on my new S3. The colors look "burning" for the transparent pixels. Opaque pixels look all fine.


If you want, here is a picture of my problem:



Nobody really seems to know that problem so I'm thinking it might be a problem with my phone.

I made a very small test program to show this. You may download the code here:


or if you only want to test it you will find the .apk here:


So everyone - even if you are not a programmer - may help me finding the problem.


I would be very, very glad for any information about this.

Even if you tell me it works perfectly fine on your S3. After all than I would know I have a problem with my phone!

Thank you very much for your help!


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Alright, I got an answer for that.

The problem was the premultiplication for the alpha values.

So in the easiest way it is enough to write:


vec3 color = clamp(textureColor.rgb * lightWeighting.xyz, 0.0, 1.0);

color *= 0.5; // premultiply by alpha

gl_FragColor = vec4(color, 0.5);


Even though I don't see why it worked perfectly fine on older systems and it I'm still not sure how to manage this on Gl1.0 where I can't write my own shader code.

So hope this helps to anyone who has the same problem!



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