Tapestry scroller

Any discussions related to the creation of new hardware or software for the ZX80 or ZX81
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nollkolltroll
Posts: 325
Joined: Sat Sep 27, 2014 8:02 pm
Location: Stockholm, Sweden

Tapestry scroller

Post by nollkolltroll »

For a very long time I've admired the demo effect of scrolling or panning a long picture. Not for its technical merit, which is not that hard to do, but for its artistic value in presenting still pictures that morph.
M.C. Escher is a long time favorite artist of mine, and his Metamorphosis I+II+III are very good pictures to show off this technique.

This tapestry scroller works on a ZX81 equipped with a ZXpand. Since the hires graphics are streamed from the SD-card one line at a time, it is possible to scroll pictures that are as long as the card will fit, which is VERY long.

The only real technical challenge in this project was to make the video routine able to wrap around an 8k boundary in real time.

Source code is enclosed, released as public domain. Hopefully someone will get some joy from it.

The file meta50.p works at 50Hz.
The file meta60.p works at 60Hz.
They both stream data from the meta.bin file.

/NollKollTroll, November 2018
Attachments
tapestry.zip
(316.76 KiB) Downloaded 226 times
/Adam
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