Re: A85: Fade to white


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Re: A85: Fade to white




The contrast is actually controlled by port 2, not the memory address.  The
only reason the memory address is there is because the port is write only.
Just use  out (2),a  after  ld (CONTRAST),a

>I don't know if I'm going to add this to my game, but I wrote a fade to
>white routine since I've never seen this effect in a game.  I can't get
>it to work and I have no idea why.  You're supposed to press a key to
>start the fade out process, then when it is done fading, you are supposed
>to press a key again.  The second pause works, but the first doesn't. 
>Here's the code:
>
>#include "usgard.h"
>
>   .org  0
>   .db   "Fading effects "
>   .db   "by Erik Gillespie", 0
>
>start:
>   call  CLEARLCD
>   sub   a
>   ld    (CURSOR_ROW), a
>   ld    (CURSOR_COL), a
>   ld    hl, &T_FadeOut
>   call  D_ZT_STR
>   call  GetCh
>   call  FadeToWhite
>   sub   a
>   ld    (CURSOR_ROW), a
>   ld    (CURSOR_COL), a
>   ld    hl, &T_DoneFading
>   call  D_ZT_STR
>
>GetCh:
>   call  GET_KEY
>   or    a
>   jr    z, GetCh
>   ret
>
>FadeToWhite:
>   ld    a, (CONTRAST)
>   push  af
>   ld    bc, 200            ; Wait 4/25 of a second before fading any
>more
>FTWLoop:
>   dec   a
>   ld    (CONTRAST), a
>   #fncall  DELAY
>   cp    0
>   jr    nz, FTWLoop
>   pop   af
>   call  CLEARLCD
>   ld    (CONTRAST), a
>   ret
>
>T_FadeOut:
>   .db   "Fading to white", 0
>T_DoneFading:
>   .db   "Done fading", 0
>
>.end
>
>
>
>egillespie@juno.com
>
>"In a prototypical world, nothing ever goes wrong." -Scott Meyers
>
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--
Brian Leech
butvis@mindspring.com
ICQ UIN: 1355611




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