It's been a while since this was sent, but hey, the list is
stagnating anyway...
Call me a control freak, but I happen to like to know *HOW* this
works so that I can make my own routine if I need to... not that I
don't trust anyone, it's just that old saying, "Give a man a
fish..., teach a man to fish..."
Also, quick question: is there any way to do shading in ASM. So,
instead of drawing in a box using _ILINE, is there a routine to shade
in a region quickly instead of drawing it line by line?
On 11 Jan 98 at 14:12, Harper Maddox wrote:
>
> A routine for this wouldnt be all that difficult. If you look at
> the .asm file outputted by pic83 you'll notice that the right part
> on the .db 's has mostly 0,0,0's
>
> here is how a routine would work...
>
>
> ; To Use this routine properly you must clip off any 0,0,0's from
> the .db
>
> ImgCtr = SAVESSCREEN
> ROWS = 2 ; number of bytes across /8 If it is a fraction round
> up... ie. 9/8 =2
>
> LftImage:
> ld hl,repback ; location to *grab* data from
> ld de,plotsscreen ; start of graphbuffer
> ld bc,ROWS*64 ; this is number of times hl needs to be incremented
> ld a,0 ; start ImgCtr at 0 ld (imgctr),a
> ImgLoop1:
> ld (de),(hl) ; not sure if its legal... if it isnt then do this:
> ld
> a,(hl) / ld (de),a
> inc hl
> inc de
> dec bc
> ld a,c
> AND B
> cp 0
> ret z ; quit if BC=0
> ld a,(ImgCtr)
> inc a
> ld (ImgCtr),a
> cp ROWS
> jr nz,LftImage ; If ImgCtr /= rows goto Lftimage
> push bc
> ld b,12-ROWS ; times it will move around the graph buffer
> ImgLoop2:
> inc de
> djnz ImgLoop2
> ld a,0
> ld (ImgCtr),a
> jr ImgLoop1
>
> This should work...
> Reply back if it doesnt.
> -harper
Jonathan Wang
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jonathan_wang@hotmail.com
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