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⌂ ∞ Elite on the BBC Micro and NES

Icon bar: Draw4OptionTiles

[NES version, Bank 3]

       Name: Draw4OptionTiles                                        [Show more]
       Type: Subroutine
   Category: Icon bar
    Summary: Draw four tiles over the top of an icon bar button in the Pause
             icon bar to change an option icon to a non-default state

    Context: See this subroutine in context in the source code
 References: This subroutine is called as follows:
             * SetupIconBarPause calls Draw4OptionTiles




 Arguments:

   Y                    The tile column of the top-left tile in the 2x2 block of
                        four tiles that we want to draw

   SC(1 0)              The address of the nametable entries for the on-screen
                        icon bar in nametable buffer 0

   SC2(1 0)             The address of the nametable entries for the on-screen
                        icon bar in nametable buffer 1



 Returns:

   Y                    Y is preserved



.Draw4OptionTiles

 SETUP_PPU_FOR_ICON_BAR ; If the PPU has started drawing the icon bar, configure
                        ; the PPU to use nametable 0 and pattern table 0

 JSR Draw2OptionTiles   ; Call Draw2OptionTiles to draw two tiles over the top
                        ; of the option icon specified in Y

 INY                    ; Increment Y to move along to the next tile column

                        ; Fall through into Draw4OptionTiles to draw two more
                        ; tiles