[stella] Supercharger RPG bare beginnings - request for help

[bob.montgomery at thomson.com]

Hi,

>> What I have right now is a tile-based, scrolling map partially based
on
>> Andrew Davie's Boulderdash engine, adapted to the confines of the SC.
>> The screen shows an 8x7 window of a 48x42 tile map, plus sprites.
>
>So, you are using code you got from Andrew? I know that one pretty
>well, since I helped optimizing some parts of it.

I should have been a bit more specific: my scrolling map is based on
Andrew's concept*, not his actual code.  I've never seen his code,
though I did look for it here and at AA.

*Using 4x24 PF pixels with color blending for each tile.  If you run the
binary you'll see what I mean.

>So you are already double buffering the display, right?
>
>I found RMW very, very slow when trying to scroll the display in my
>Paradroid demo. Especially fast writing is a big problem. How does
>your scrolling work, compared with Andrew's?

It isn't exactly a *double* buffer, but I am buffering the display,
kinda.  

The display RAM is a series of addresses in the kernel code; I write the
new addresses to a chunk of RAM (the buffer) and, after they are all
updated, I copy them all at once to the kernel.

I don't think the method of scrolling is similar - though I'm not sure.


Thanks,

-bob