Re: NES emulator hack that might be interesting

From: smf <smf_at_null.net>
Date: Fri, 31 Aug 2018 18:17:51 +0100
Message-ID: <740a9faf-ed33-cb96-481d-22f81d2e75fe@null.net>
On 31/08/2018 17:28, Mia Magnusson wrote:
> It could however be implemented in Amiga emulators. Commodore but not
> 8-bit :)

Amiga adds further complexities

http://codetapper.com/amiga/sprite-tricks/shadow-of-the-beast/

http://codetapper.com/amiga/sprite-tricks/brian-the-lion/

http://codetapper.com/amiga/sprite-tricks/jim-power/

> The trouble is how to know beforehand where the screen starts/stops
> vertically. Horisontally it's more or less just to have a look at the
> modulo registers, except that you might get garbage to the left of the
> "official" screen on the first line and to the right of the last line,
> and you can't really tell where one line ends and the next starts so
> you could see some horisontal wrap in the extended screen area.

modulo registers wouldn't normally change, just the bit plane pointers.

You'd only ever be able to grab out of memory what is actually displayed, which is why you need to time travel into the future while virtually pushing the joystick to find what data is coming up.

> One problem is that you won't be able to know how computer generated
> characters behave if they either have some random element to them or if
> the player interacts with them in any ways.

They'll normally be sprites. But it'll be best guesses, you won't ever 
have that much change in the character map but the changes will look 
glitchy.

Although these would likely be a problem....

https://www.youtube.com/watch?v=mW4w32UihGE

https://www.youtube.com/watch?v=SiCxXMquPKs

> I think that for a C64 or similar, you'll have to write code specific
> to every game to make it work perfectly.

Yeah, personally I'd probably do that and get bored after one game...

> For some games, like Scramble type games, the playable area is really
> wide, so there is a question of how much screen should be displayed.

I believe the answer is, "enough to fill a 16:9 monitor".
Received on 2018-08-31 20:00:05

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