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  1. #1
    Registered User
    Join Date
    Jan 2008
    Posts
    2

    Blank screen when SimpleCube is built with vfpv2 on Nokia 5800

    I'm having trouble getting my application code to work with OpenGLES on the Nokia 5800 when built as ARM with FPU support enabled.

    The application installs o.k. and I can even step through the code with AppTrk and see what appears to be correct looking assembler for FPU operations.

    The problem is that the output of OpenGLES is either missing or very badly corrupted. This is easily reproducible in the SimpleCube application.

    Just add
    always_build_as_arm
    armfpu vfpv2
    and build with RVCT

    Does anyone know whether this can work or does OpenGLES not work at all with FPU on the 5800 ?

    N.B. I'd rather not rewrite my application engine to be fixed point even if it has to interface with a fixed point implementation (does 5800 OpenGLES utilise FPU?) of OpenGLES.

  2. #2
    Regular Contributor
    Join Date
    Apr 2004
    Posts
    96

    Re: Blank screen when SimpleCube is built with vfpv2 on Nokia 5800

    The problem could be that OpenGL floating point API functions are bugged. You can test this if you use your floating point code, but convert data to fixed point only while calling OpenGL ES function (fixed point OpenGL ES functions end on x)

  3. #3
    Registered User
    Join Date
    Jan 2008
    Posts
    2

    Smile Re: Blank screen when SimpleCube is built with vfpv2 on Nokia 5800

    Thanks, I managed to get the code working using GCCE and this seems to be because I specified -mfloat-abi=softfp.

    Perhaps the RVCT with vfpv2 was defaulting the equivalent of -mfloat-abi=hard and passing float parameters by register which wouldn't work if OpenGL was built with softfp.

    Anyway, to I'm now using fixed point for all of the vertex data to improve performance.


    OPTION gcce -O3
    OPTION gcce -mfpu=vfp
    OPTION_REPLACE gcce -msoft-float -mfloat-abi=softfp

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