You should probably use some GL_NEAREST (or something like that) for the full resolution tile, and some interpolation for the rest if thats possible (though i dont know if you should use nearest for those too) when setting the setting up the texture.

You should probably use some GL_NEAREST (or something like that) for the full resolution tile, and some interpolation for the rest if thats possible (though i dont know if you should use nearest for those too)