OpenGL ES 2.0 screen flickering

Question

I'm facing a big problem. I'm using a Transformer tf101 tab with Android 4.0.3 on it.

My app is using a custom OpenGL ES 2.0 surface. I'm rendering multiple planes with textures. this textures are changing approx. 20 times per second and are updated by passing byte arrays. However, in certain cases, the screen begins flickering and does not render the new textures. Additional UI Elements are still responsive and do their work as intended. It seems the OpenGL context ignores all commands and is unresponsive.

When this happens, a few lines show up in my logCat:

08-20 10:31:15.390: D/NvOsDebugPrintf(2898): NvRmChannelSubmit: NvError_IoctlFailed with error code 1

followed by

08-20 10:31:15.390: D/NvOsDebugPrintf(2898): NvRmChannelSubmit failed (err = 13, SyncPointValue = 879005, returning = 0)

and a few of them:

08-20 10:31:15.390: D/NvOsDebugPrintf(2898): NvRmChannelSubmit failed (err = 196623, SyncPointValue = 0)

Here is how i create my Textured Plane:

    m_nTextureStorage[0] = 0;

    GLES20.glGenTextures( 1, m_nTextureStorage, 0);
    GLES20.glActiveTexture( GLES20.GL_TEXTURE0 );
    GLES20.glBindTexture( GLES20.GL_TEXTURE_2D, m_nTextureStorage[ 0 ] );

    // Set filtering
    GLES20.glTexParameterf( GLES20.GL_TEXTURE_2D, GLES20.GL_TEXTURE_MIN_FILTER, GLES20.GL_NEAREST );
    GLES20.glTexParameterf( GLES20.GL_TEXTURE_2D, GLES20.GL_TEXTURE_MAG_FILTER, GLES20.GL_NEAREST );
    GLES20.glTexParameteri( GLES20.GL_TEXTURE_2D, GLES20.GL_TEXTURE_WRAP_S, GLES20.GL_CLAMP_TO_EDGE );
    GLES20.glTexParameteri( GLES20.GL_TEXTURE_2D, GLES20.GL_TEXTURE_WRAP_T, GLES20.GL_CLAMP_TO_EDGE );

and here is how i draw it:

GLES20.glEnable(GLES20.GL_TEXTURE_2D);
        GLES20.glEnable(GLES20.GL_DEPTH_TEST);
        GLES20.glActiveTexture( GLES20.GL_TEXTURE0 );

        //GLES20.glUniformMatrix4fv(m_HMVPMatrixUniform, 1, false, mvpMatrix, 0); 
        GLES20.glUseProgram( m_nProgramHandle );
        ByteBuffer oDataBuf = ByteBuffer.wrap( m_sTexture );

        m_HTextureUniform = GLES20.glGetUniformLocation( m_nProgramHandle, "uTexture" );
        m_HTextureCoordinate = GLES20.glGetAttribLocation( m_nProgramHandle, "TexCoordinate" );
        GLES20.glUniform1iv( m_HTextureUniform, 2, m_nTextureStorage, 0 );

        // get handle to the vertex shader's vPosition member
        m_nPositionHandle = GLES20.glGetAttribLocation( m_nProgramHandle, "vPosition" );


        // Prepare the triangle data
        GLES20.glTexImage2D( GLES20.GL_TEXTURE_2D, 0, GLES20.GL_LUMINANCE, 640, 480,
                             0, GLES20.GL_LUMINANCE, GLES20.GL_UNSIGNED_BYTE, oDataBuf );

        // Prepare the triangle data
        GLES20.glVertexAttribPointer( m_nPositionHandle, 3, GLES20.GL_FLOAT, false, 12, m_oVertexBuffer );
        GLES20.glEnableVertexAttribArray( m_nPositionHandle );

        GLES20.glVertexAttribPointer( m_HTextureCoordinate, 2, GLES20.GL_FLOAT, false, 12, m_oTextureBuffer); 
        GLES20.glEnableVertexAttribArray( m_HTextureCoordinate );

        m_nMVPMatrixHandle = GLES20.glGetUniformLocation( m_nProgramHandle, "uMVPMatrix");

        // Apply the projection and view transformation
        GLES20.glUniformMatrix4fv( m_nMVPMatrixHandle, 1, false, mvpMatrix, 0);

        GLES20.glDrawArrays(GLES20.GL_TRIANGLES, 0, 6);

The OpenGL Renderer simply calls the draw function of my TexturedPlane by passing the mvpMatrix. Im not deleting any textures since i've read that the android system will take care of that automatically.

I think it has something todo with the GPU going OOM, but im not sure since i haven't found anything related to the posted error messages.

Thanks it advance!

UPDATE:

The Rendermode was set to RENDER_WHEN_DIRTY . After Changing it to RENDERMODE_CONTINOUSLY the problem disappears.. Weird. Since this is just a workaround and no solution, I'm still asking for help ;)

Leaving the Rendermode at continuously is no option, since this consumes to much processor time and makes no sense, since rendering is only necessary when new textures a generated.

Answer 1

Finally found the solution.

When i call glFlush() after every rendering circle, it works fine. I no render every plane on a different texture channel, it works perfectly so far. Thanks for the help.

Answer 2

When you call ..:

GLES20.glUniform1iv( m_HTextureUniform, 2, m_nTextureStorage, 0 );

I think that binds a particular texture unit to the sampler uniform. But you're passing a texture name/object/handle/whatever (which is not a texture unit.) Maybe it's just coincidence, and you only ever pass in 0 (which is possibly the texture name in m_nTextureStorage,) which is coincidentally the correct/desired value?

Or maybe this results in the user-space driver crashing.