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Krill
Registered: Apr 2002
Posts: 2980 |
Looking for a specific obscure ancient demo with a very interesting bitmap stretcher
... which DeeKay (are you reading this?) once showed me. It features a bitmap stretcher which has been baffling him as it has baffled me, as it seemed to be able to stretch every line (not just the badlines) but still showed a bitmap that was around 20 or more char rows high and colourful (not just 3+1 colours). The stretching patterns seemed a little weird, so there might be a connection to this feat.
It must have been from around 1988-1990 (yes, i know, there's a shitload of obscure demos from that era) and is on CSDb.
I've wanted to take a closer look at the code ever since, but alas, failed to re-locate the demo. |
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lft
Registered: Jul 2007
Posts: 369 |
Exactly, Krill clarified what I described.
Now for an improvement (which may or may not be done in the demo). Suppose your sine tables are set up so that each row of graphics can stretch to at most 13 lines. Then you can get away with six bitmaps, which in turn means that they don't have to be half-height anymore.
Each column in the following table corresponds to one bitmap bank. The eight lines of graphics that make up one row are distributed according to the lines of the table. Now it's possible to stretch the first line up to five times, and then find a way down to line RC=7 that stretches any line(s) up to 5x along the way.
012345
123456
234567
34567
4567
567
67
7
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ChristopherJam
Registered: Aug 2004
Posts: 1409 |
Argh! Of course. Because the original was a perfectly ordinary koala, no extra char DMA is needed after the first line in each section. Thanks for pointing out the obvious, I feel a bit silly now :) |
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ChristopherJam
Registered: Aug 2004
Posts: 1409 |
Speaking of ancient demos with interesting bitmap stretchers, does anyone remember a row-by-row stretcher featuring the Hunters Moon loading screen and music?
It just introduced black gaps between character rows, but it was the first time I'd seen the effect - jaw dropping.
I always just thought of it as "the hunters moon demo," but it's apparently not the production with that title here. |
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Krill
Registered: Apr 2002
Posts: 2980 |
I remember that FLD effect being used by at least one of the versions of The Syndicate/Beastie Boys' "Picture Linker" tools, http://csdb.dk/search/?seinsel=all&search=picture+linker. But this didn't link music, it just played that classic ringmod hum, iirc.
Anyways, maybe it wasn't a regular demo but just the loading pic linked with that intromaker-like tool? Or a crack of the game with the loader picture linked using this tool? |
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