Routines
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A247: Select Draw Sprite
Used by the routines at PrepareDraw and UpdateStarLayer.
Sets up the second sprite, which is the sprite that is drawn by DrawSprites.
Input
B Number of rows
C Index of the routine that draws the sprite
H Width in bytes
Output
B High byte of the shift table to use
IX Address of the routine that draws the sprite
SelectDrawSprite A247 LD A,B Fetch the number of rows.
A248 LD ($A1D8),A Store it.
A24B LD A,H Fetch the width.
A24C LD ($5C29),A Store it.
A24F LD HL,$A2AA Use the table of routines that draw sprites.
A252 CALL GetTableEntry Fetch the address of the routine.
A255 PUSH HL Put it in IX.
A256 POP IX
A258 LD A,($A1D5) Fetch the horizontal position of the second sprite.
A25B JR SelectEraseSprite_Shift Jump to SelectEraseSprite_Shift.
This entry point is used by the routine at SelectEraseSprite.
SelectEraseSprite_Position A25D LD A,($A1D3) Fetch the horizontal position of the first sprite.
SelectEraseSprite_Shift A260 AND %00000110 Only bits 1 and 2, which are the number of pixels to shift by.
A262 ADD A,$F8 Add the high byte of the shift table that does no shifting.
A264 LD B,A Store it in B.
A265 RET Return.
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