https://forums.rpgmakerweb.com/index.php?threads/scrolling-b

#==============================================================================
#** NS
#==============================================================================
class NS;
end #NS

#==============================================================================
# ** NS::Battle_Plane
#==============================================================================
class NS::Battle_Plane
    # Switch to Enable Scrolling Background
    Enable_Switch    = 15
    # Variables for Horizontal and Vertical Scroll Speed
    Back1_X_Variable = 10
    Back1_Y_Variable = 11
    Back2_X_Variable = 12
    Back2_Y_Variable = 13
end # NS::Battle_Plane


#==============================================================================
#** Spriteset_Battle
#==============================================================================
class Spriteset_Battle

    #--------------------------------------------------------------------------
    #* Create Battle Background (Floor) Sprite
    #--------------------------------------------------------------------------
    unless method_defined?(:battleback_C42W53GD_sb_create_battleback1)
        alias_method(:battleback_C42W53GD_sb_create_battleback1, :create_battleback1)
    end

    def create_battleback1(*args, &block)
        if $game_switches[NS::Battle_Plane::Enable_Switch] == true
            @back1_sprite = Plane.new(@viewport1)
            @back1_sprite.bitmap = battleback1_bitmap
            @back1_sprite.z  = 0            @back1_sprite_ox = 0
            @back1_sprite_oy = 0
        else
            battleback_C42W53GD_sb_create_battleback1(*args, &block)
        end
    end

  #--------------------------------------------------------------------------
  # * Create Battle Background (Wall) Sprite
  #--------------------------------------------------------------------------
    unless method_defined?(:battleback_ms67JgWE_sb_create_battleback2)
        alias_method(:battleback_ms67JgWE_sb_create_battleback2, :create_battleback2)
    end

    def create_battleback2(*args, &block)
        if $game_switches[NS::Battle_Plane::Enable_Switch] == true
            @back2_sprite = Plane.new(@viewport1)
            @back2_sprite.bitmap = battleback2_bitmap
            @back2_sprite.z = 1      @back2_sprite_ox = 0
            @back2_sprite_oy = 0
        else
            battleback_ms67JgWE_sb_create_battleback2(*args, &block)
        end
     end
  #--------------------------------------------------------------------------
  #* Update Battle Background (Floor) Sprite
  #--------------------------------------------------------------------------
    unless method_defined?(:battleback_HNirC0QE_sb_update_battleback1)
     alias_method(:battleback_HNirC0QE_sb_update_battleback1, :update_battleback1)
    end

    def update_battleback1(*args, &block)
        if $game_switches[NS::Battle_Plane::Enable_Switch] == true
            @back1_sprite_ox += $game_variables[NS::Battle_Plane::Back1_X_Variable].to_f / 64
            @back1_sprite_oy += $game_variables[NS::Battle_Plane::Back1_Y_Variable].to_f / 64
            @back1_sprite.ox = @back1_sprite_ox * 16      @back1_sprite.oy = @back1_sprite_oy * 16
        else
            battleback_HNirC0QE_sb_update_battleback1(*args, &block)
        end
    end

    #--------------------------------------------------------------------------
    # * Update Battle Background (Wall) Sprite
    #--------------------------------------------------------------------------
    unless method_defined?(:battleback_zmrQkMCU_sb_update_battleback2)
        alias_method(:battleback_zmrQkMCU_sb_update_battleback2, :update_battleback2)
    end

    def update_battleback2(*args, &block)
        if $game_switches[NS::Battle_Plane::Enable_Switch] == true
            @back2_sprite_ox += $game_variables[NS::Battle_Plane::Back2_X_Variable].to_f / 64
            @back2_sprite_oy += $game_variables[NS::Battle_Plane::Back2_Y_Variable].to_f / 64
            @back2_sprite.ox = @back2_sprite_ox * 16      @back2_sprite.oy = @back2_sprite_oy * 16
        else
            battleback_zmrQkMCU_sb_update_battleback2(*args, &block)
        end
    end

end # Spriteset_Battle