fix render_to_image, add clear depth buffer
fix render_to_image, add clear depth buffer

yglukhov/nimx,bogdan-voevoda/nimx,rrenderr/nimx,bogdan-voevoda/nimx,rrenderr/nimx,rrenderr/nimx,yglukhov/nimx,qqquinta/nimx,qqquinta/nimx,bogdan-voevoda/nimx,qqquinta/nimx,yglukhov/nimx