19 May 2021, 23:02 | #21 | ||
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Actually, the way I get to 4 pixels per colour is using exactly such a trick. You can do 1 pixel Copper Chunky this way, but it'll only be at most 56 pixels wide because of Copper speed limitations Quote:
As for the mushroom, I haven't actually eaten any ever. What happened is that I needed three pictures and after choosing the one of my cat, I wanted to add more colour so I picked one I took at the zoo and one I took in the forest |
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20 May 2021, 12:34 | #22 | |
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From the above one can see that this trick is only really well suited for slow & continuous rotations, as you cannot rotate by an arbitrary angle without intermediate steps. That usually gives that kind of effect away. IIRC, the rotating skull in WoC/Sanity uses the same technique. But back on topic, very nice work & documentation, roondar. Thanks for sharing! But back on topic, really |
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20 May 2021, 17:36 | #23 |
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Nice video and nice tone on the presentation. Big thumbs up.
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20 May 2021, 17:38 | #24 | |
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@Roondar: Thank you. Very nice reading. I was experimenting with copper-chunky during my youth years back in '93 or '94. I didn't know about 7bpls trick back then though, so I was combining bitplanes with sprites. Photon's rotozoomer (which you mentioned) does it too? Does it allow him to stop bitplanes fetching sooner so that CPU can access chip-ram?
Btw I'm not sure about this passage in your article: Quote:
Also, I remember that eventually coders used interlace copper-chunky technique more often (copper color change every 8 pixels with a 4 pixel mask which is swapped every line and frame) as it allows full-screen. Looks ugly and dark though My suggestion for your next article: Zooming, or "star-wars scroller" :-) Is it really possible by modyfing bplcon2 along the line only? |
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20 May 2021, 17:46 | #25 | ||||
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Edit: fixed the article, it now correctly refers to Agnus doing the fetching rather than Denise. Thanks for pointing it out Quote:
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Last edited by roondar; 20 May 2021 at 21:56. |
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20 May 2021, 21:27 | #26 |
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Excellent video! Also the ones before were great.
While watching it I got one probably stoopid too idea. In order to have "higher" vertical resolution, would it be possible to update odd than even lines every other frame. Maybe even having two bitmaps, one with y+1 offset and switching between them... Something like low res interlace. And how would that compare to flat 25fps... |
20 May 2021, 21:58 | #27 | |
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Thanks
Quote:
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23 May 2021, 10:55 | #28 |
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@roondar: Enjoyed each of your videos so much. Thanks a lot for sharing your expertise, and creating code and videos!
Edit: Did read your written feature too. Amazing stuff. Last edited by buzzybee; 23 May 2021 at 11:08. |
24 May 2021, 12:41 | #29 |
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I wonder where OCS/ECS copper chunky technique appeared for the very first time.
According to Pouet: Announce / Lemon (March 1993) Desert Dream / Kefrens (April 1993) and much later: Arte / Sanity (November 1993) My guess is that it all happened under a strong influence of the famous rotozoomer in World of Commodore / Sanity (November 1992), which is not done using copper chunky though. I know a lot of productions were using copper color modifications + bpl data to squeeze images (usually scroll texts) many years before, but I don't count them as an emulation of chunky buffer per se. P.S.: I also wonder if all those plasma effects were some kind of precursors. Last edited by defor; 24 May 2021 at 16:53. |
24 May 2021, 13:53 | #30 | |
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I remember when it was released, and thinking that it was a nice variation on another one that I'd seen. Will have to have a dig around and see what it was |
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03 June 2021, 19:53 | #31 |
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Great stuff! Thanks for creating these!
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03 June 2021, 20:43 | #32 |
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Always interesting to read Amiga article of yours mate.
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04 June 2021, 11:57 | #33 |
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Excellent stuff and big thumbs up for your explanation skills
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25 September 2023, 12:05 | #34 |
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Any examples of demos that made use of this technique? And would this not be prone to flickering?
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28 September 2023, 15:53 | #35 |
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I don't know if anyone released copper-chunky before I released Announce, but I definitely had never seen any before I wrote my version.
The routine from WoC was directly the inspiration - Chaos had snailmailed me that routine as a standalone executable, as a preview for an upcoming demo. I quickly came up with the copper version. I could actually have included it in 3d demo 2 as I had written the effect before its' release. However, I wasn't great at keeping up with new releases, so I didn't see WoC until afterwards, and didn't want to break his trust by releasing my version before him. |
29 September 2023, 10:56 | #36 |
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@Hannibal
That is a nice background story. Thanks for sharing. I would have liked to see Chaos's face :-) And hadn't you made use of the $102 zoom/shrink trick - though in a very basic version - before Chaos came up with Optimum Fuckup? I seem to remember of having read sth like this. |
29 September 2023, 16:25 | #37 |
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Yeah, 102 zooming in Last Dimension - but not combined with prescaled images, so Chaos' version was much more impressive
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