Switching attachments for an FBO works on PC emulation but fails on my device

This topic contains 3 replies, has 2 voices, and was last updated by  Joe Davis 4 years, 9 months ago.

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  • #31156

    mkandula
    Member

    Hi,

    I am attaching different textures to the same FBO so that I can render normals to one texture, light accumulation to the other an so on.
    I ofcourse check for frame buffer completeness, glErrors etc and everything is fine on PC side. But on my android device (Galaxy S1 I9000), there is a huge rendering problem where this mechanism fails and does not throw any of the errors also (GL_FRAMEBUFFER_COMPLETE is returned and no gl errors).

    If I avoid doing this switching of attachments to the FBO (just render normals to a single attachment of the FBO) and go back to check, there are no rendering problems.

    So at this point, I am not sure if there is a bug in my code or my device or PVR SDK. So I will email the apk file, screen shots of PC emulation for comparison. Please help by testing on other devices and/or providing suggestions to debug my problem.

    #36728

    Joe Davis
    Member

    Hi,

    This is a known issue in the 1.6 driver on the Galaxy S. You can work around it by using separate FBOs for each texture attachment.

    Our OGLES2 DeferredShading Example implements a render in this way.

    Thanks,
    Joe

    #36729

    mkandula
    Member

    Thanks for your response. You gave me a huge relief 🙂

    Does that mean, it only happens on Galaxy S1 or will it happen on S2 and S3 such phones ?
    In this link,
    http://www.songho.ca/opengl/gl_fbo.html

    it is said that using multiple FBO’s approach is slower. Can you specify if this is actually true and by how much ?
    What all devices will I encounter this 1.6 driver ? Will this bee updated anytime soon ?

    #36730

    Joe Davis
    Member

    For PowerVR, an FBO per-texture is best for performance (for any version of the driver). I can’t recommend best practices for other GPU vendors – you should contact them for advice.

    Thanks,
    Joe

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