Routines
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7450: Colourise Sprite
Used by the routines at 5FDE, AnimateExplosion, 69E8, 6C53, 6D0C, 6ED2, 6EF1 and 721A.
ColouriseSprite 7450 EXX Switch to the shadow registers.
7451 LD HL,($5E1A) HL'=actor co-ordinates.
7454 CALL AttributeAddress Call AttributeAddress - HL' now holds the co-ordinates to an attribute file address.
7457 LD A,($5E0F) B'=width loop counter (in pixels).
745A LD B,A
745B LD A,($5E0E) A=5E0E.
745E RRCA A=((A / 04) + 01) / 02.
745F RRCA
7460 INC A
7461 RRCA
7462 AND %00011111 Keep only bits 0-4.
7464 INC A Increment A by one.
7465 LD C,A C=height loop counter (in pixels).
7466 LD D,(IX+$03) D=object colour attribute.
7469 LD E,B E=width loop counter (in pixels).
ColouriseSprite_Loop1 746A PUSH HL Stash HL on the stack.
ColouriseSprite_Loop2 746B LD A,H A=actor Y position.
746C CP $5B Decrement position if address is outside of attribute file address range.
746E JR NC,ColouriseSprite_1
7470 CP $58
7472 JR C,ColouriseSprite_1
7474 LD (HL),D Otherwise, set the colour at this location.
7475 INC L Next tile column.
7476 LD A,L Next tile if column < screen width (32 chars).
7477 AND %00011111
7479 JR NZ,ColouriseSprite_0
747B LD A,L else, wrap-around and continue applying colour.
747C SUB $20
747E LD L,A L=start of current row.
ColouriseSprite_0 747F DJNZ ColouriseSprite_Loop2 Decrease counter by one and loop back to ColouriseSprite_Loop2 until counter is zero.
ColouriseSprite_1 7481 POP HL Restore HL from the stack.
7482 PUSH BC Stash BC on the stack.
7483 AND A Clear the carry flag.
7484 LD BC,$0020 HL -= 32 tiles. Places address pointer previous line.
7487 SBC HL,BC
7489 POP BC Restore BC from the stack.
748A LD B,E B=reset to original width counter.
748B DEC C Decrement height counter.
748C JR NZ,ColouriseSprite_Loop1 Repeat until all tiles have been coloured.
748E RET Return.
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