Posted by Wade Walker on Mar 22, 2012; 1:07pm
URL: https://forum.jogamp.org/blank-screen-by-shader-render-tp3848071p3848410.html

I noticed that in glBufferData, you're passing the number of floats as the size, but it should be the size in bytes instead (so number of floats * 4). There's the same problem with your index buffer (should be number of shorts * 2).

You might also want to check the GL error status after every GL call that might set it. This can find errors that might leave you puzzled for a very long time  I usually define a function like this:

    /**
     * Checks if there have been any GL errors. Throws an exception with the
     * error codes in the message if there have been.
     * @param gl Used to make GL calls.
     * @param sFuncName Name of GL function we're checking for errors after.
     */
    public static void checkGLError( GL2ES2 gl, String sFuncName ) {

        int iError;
        StringBuilder sb = null;
        do {
            iError = gl.glGetError();
            if( iError != GL.GL_NO_ERROR ) {
                if( sb == null )
                    sb = new StringBuilder();
                sb.append( sFuncName + " failed, GL error: 0x" + Integer.toHexString( iError ) + "\n" );
            }
        }
        while( iError != GL.GL_NO_ERROR );

        if( sb != null )
            Assert.assertTrue( sb.toString(), false  );
    }

and call it after every GL function that can set an error code.