docs: public boolean startClipped (int x, int y, int width, int height) {
      batch.flush(); // flush any pending unclipped calls
      Rectangle r = pushScissorState(x, target.flip() ? target.height()-y-height : y, width, height);
      batch.gl.glScissor(r.x, r.y, r.width, r.height);
      if (scissorDepth == 1) batch.gl.glEnable(GL20.GL_SCISSOR_TEST);
      batch.gl.checkError("startClipped");
      return !r.isEmpty();
    }