[A82] Re: game graphics compression

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[A82] Re: game graphics compression


The original NES version used some badass compression!

The rooms were made up of _objects_, each 2 bytes.  These could be chozos, 
balls, floors, lava, etc.  The first was a location (2 nibbles, x and y), 
the next one was an object type.  The objects were horizontally as bytes: 
like:

00,01,FF
01,00,FE

(this is a 2x2 block)

Then it went even further: it repeated rooms as a megatilemap, each byte one 
room!  It changed scrolling direction on doors.

Not sure if the above info would be of any help though.



>From: Harper Maddox <gte172i@prism.gatech.edu>
>Reply-To: assembly-82@lists.ticalc.org
>To: assembly-82@lists.ticalc.org
>Subject: [A82] Re: game graphics compression
>Date: Tue, 20 Feb 2001 22:50:17 -0500
>
>
>I don't know how it performs on a large scale map, but I made a RLE based
>algorithm yesterday that allowed me to stuff a 8x20 tilemap into 6 bytes.
>I think metroid would favor a RLE based algorithm, since there is alot of
>blank space in the middle of the map.  Many times a row on the screen just
>takes up 2 bytes.
>Here is how my algorithm works:
>
>map:
>   .db <tileID>,<x numTiles>              ; way ONE - signifies that the
>next X tiles are of type tileID
>   .db <tileID, bit 7 set>                        ; way TWO - draw only one
>tile of tileID
>   .db <tileID, bit 6 set>,<numTiles>     ; way THREE - draw X total tiles,
>consisting of the tile at tileID, and the next tile
>                                          ;   essentialy repeats a 8x16 
>tile
>x/2 times
>
>i can send you the 8x8 tile implementation if anyone is interested.
>
>-harper
>
>ps. this tilemap routine is for a "secret" project, which is an old
>nintendo game.
>
>At 03:34 AM 2/21/01 +0000, you wrote:
>
> >hiya, i am starting up work again on my ti82 metroid project
> >i need a compression method for graphics with a low ammount of 
>redundancy.
> >not ZCP or EZCMP which is all i could find. i need a ratio of 80% (more
> >specifically, to be able to stuff 512 bytes into 400)- can anybody help? 
>ive
> >tried thinking of my own compression scheme but its too complicated! 
>thanks
> >
> >- roger
> >_________________________________________________________________
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>
>

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