Drawing sprites: HideMoreSprites

       Name: HideMoreSprites                                         [Show more]
       Type: Subroutine
   Category: Drawing sprites
    Summary: Hide X + 1 sprites from sprite Y / 4 onwards
    Context: See this subroutine in context in the source code
 References: This subroutine is called as follows:
             * HideMostSprites calls HideMoreSprites


 This routine is similar to HideSprites, except it hides X + 1 sprites rather
 than X sprites.


 Arguments:

   X                    The number of sprites to hide (we hide X + 1)

   Y                    The number of the first sprite to hide * 4


.HideMoreSprites

 LDA #240               ; Set A to the y-coordinate that's just below the bottom
                        ; of the screen, so we can hide the required sprites by
                        ; moving them off-screen

.hisp1

 STA ySprite0,Y         ; Set the y-coordinate for sprite Y / 4 to 240 to hide
                        ; it (the division by four is because each sprite in the
                        ; sprite buffer has four bytes of data)

 INY                    ; Add 4 to Y so it points to the next sprite's data in
 INY                    ; the sprite buffer
 INY
 INY

 DEX                    ; Decrement the loop counter in X

 BPL hisp1              ; Loop back until we have hidden X + 1 sprites

 RTS                    ; Return from the subroutine