Routines
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6f2a: Copies the sprite pixel data to a buffer.
Note the copious amounts of register swapping! These annotations need checking. Used by the routine at 6f0b.
Input
C Number of bytes to copy?
HL Address pointing to the "height" value in a sprite header
DE Address of buffer to use.
6f2a push hl
6f2b ex de,hl Swap Sprite<->Buffer addresses
6f2c exx
6f2d pop hl HL=sprite address
6f2e pop bc C (sprite count) is the important value
6f2f push bc Copy the counter back on the stack
6f30 ld a,(hl) A=sprite height value
6f31 ex af,af' Backup "height" to A'
6f32 inc hl HL=start of sprite pixel data
6f33 exx HL=buffer, DE=sprite
6f34 ld (hl),$00 Buffer: set first byte
6f36 inc hl
6f37 ld (hl),$03 Buffer: set sprite width
6f39 inc hl Point Buffer to height variable
6f3a ex af,af' Restore A with height value
6f3b cp $11 Jump if height < 17 pixels
6f3d jr c,$6f41
6f3f ld a,$10 else height=16 pixels
6f41 ld (hl),a Buffer: height will be <= 16
6f42 inc hl Point Buffer to start of pixel data
6f43 ld b,a B=height variable
6f44 call $6ea5 Write pixel to a buffer
6f47 pop bc Reset BC to be only the sprite counter?
6f48 pop hl HL=start of buffer
6f49 ld de,$0033 HL=start of next buffer
6f4c add hl,de
6f4d pop de DE=lookup table address
6f4e ex de,hl HL=sprite, DE=buffer
6f4f inc hl HL=sprite width value
6f50 inc hl HL=sprite height value
6f51 ld a,($5dd3) A=Rocket build state - only $00 or $04?
6f54 add a,b
6f55 ld b,a
6f56 dec c Decrement the sprite counter
6f57 jr nz,$6f23 Fetch next sprite address
6f59 ret
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