Re: LZ: Re: Sprite question

To: list-zshell@lists.ticalc.org
Subject: Re: LZ: Re: Sprite question
From: Will Stokes <wstokes@vertex.ucls.uchicago.edu>
Date: Wed, 2 Jul 1997 10:47:56 -0500 (CDT)
In-Reply-To: <199707021456.HAA05149@f47.hotmail.com>
Reply-To: list-zshell@lists.ticalc.org

ask jimmy =)

On Wed, 2 Jul 1997, houston 00 wrote:

> >I have a question about sprites:
> >
> >I'm using the sprite library under usgard, but any sprite routine would 
> >have this same problem.  I'm trying to scroll a sprite across the 
> >screen, and it works perfectly except for one problem.  When I get to 
> >the complete left or top of the screen, I want the sprite to draw only 
> >the lower part or right part of the sprite.  Instead, it draws the 
> >sprite only at the bottom of the screen if I try to scroll up, and if I 
> >try to scroll left, it draws half on the very left of the screen and 
> >half on the very right of the screen.
> >
> >How the heck do I draw only the lower right corner of a sprite?
> 
> I'm making bomberman and I ran into the same problem. I haven't tested 
> anything yet but here's my basic idea: instead of using the library
> you'll have to cut and paste with the routine. The new inputs are
> d=x displacement
> e=y displacement
> Then you change the routine so that is has a loop for 
> srl a's and inc hl's   
> i.e.
> ;put this at the beginning
> Loop1:
>  inc hl
>  dec e
>  jr nz,Loop1
> ;put this every time there's a new byte
> Loop2:
>  srl a
>  dec d
>  jr  nz,Loop2
> 
> adding pushes and pops where ever neccesary. This only works with 
> PutSprite, I haven't read the code to NASR. Of course, now the obvious 
> problem is how do you do lower left corners and upper right and upper 
> left corners?!! Well, my idea is to have a  seperate routine for lower 
> left corners. Also I have a status bar at the bottom of the screen so 
> when I just need an upper corner I'll just displace horizontally, then 
> draw the status bar over the the bottom.
> 
> Having two routines and no library isn't very efficient, but its the 
> best way I can think of offhand. What routine did the author of Sqrxz 
> use?
> 
> Terry Peng
> houston00@hotmail.com
> 
> P.S. I heard that you're doing bomberman as well?!!!
> 
> _______________________________________________________
> Get Private Web-Based Email Free http://www.hotmail.com
> 

                             Biya,  
                               Will Stokes
                                 8^)
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References:

LZ: Re: Sprite question

From: "houston 00" <houston00@hotmail.com>