Seizure / Epilepsy Warning: Flickering Images!
Intellectual Property Disclaimer: Popcorn by Gershon Kingsley is not my Intellectual Property, my use of this song probably falls into the "Fair Use" (see: remix / sampling / performance) legal doctrine, I did not write "Popcorn" for God sake.
This was one of my first forays into Pico-8 programming a couple years ago that wasn't focused on sprite animations and was originally just some bouncing balls and some screen effects with no music. I felt like posting it here but thought it could use some enhancements so this is the latest revision.
Controls:
- O holds orbs that contact the ground and launches them upon release.
- X adds more orbs.
- Left changes the color palette
- Up Removes all orbs.
- Down lowers the framerate and resets at < 3 FPS
- Right lowers the Drag coefficient and reset to 1 at zero.
Current features:
- Multiple Palettes
- Adjustable Drag Parameter
- Adjustable Framerates
- Music: Butter-Flavored "Popcorn" for Pico-8 stolen by homebum from Gershon Kingsley (2024)
- Photosensitive Epilepse (PSE) Disclaimer with experimental "PSE-SAFE Mode": a frame-rate limited, "non-flickering" mode that might still be dangerous--so no guarantees on that one.
The music was created to enhance the visual experience and not the other way around if you can believe that ... It was mostly just an excuse to tinker with the music tools and watching this "demo" was getting the original "Popcorn" stuck in my head anyway so I figured I throw that in on a whim for good measure before releasing it here. Well, that "whim" ended up being like a week of effort.
I haven't really tinkered too much with Pico-8's sound effects and music editors so this is probably the most extensive use of these tools that have ever gone into any of my projects, released or otherwise. It's not and exhaustive demonstration of Pico-8 capabilities by any means but a practical example of what they can do and I feel proficient in these tools after this.
Some history on the song itself, I might have this part wrong:
- Original "Popcorn" (1969) is by German-American composer Gershon Kingsley from his album "Music to Moog By"
- Popcorn (1972) by First Moog Quartet (Gershon Kingsley) was based on the Gershon Kinglsey "Popcorn" (1969) and intended for the 1970 re-release of their self-titled album. I'm having a difficult time finding this version of the song.
- Popcorn (1972) by Hot Butter which is an American band fronted by Stan Free, a member of First Moog Quartet, was based on the First Moog Quartet re-released "Popcorn" (1972) by First Moog Quartet. This is the version of the song you usually find if you go searching.
My version "borrows" (see: plagiarizes) heavily from the 1972, Hot Butter (Stan Free) version. I think my favorite version of the song is just the 1969, Music To Moog By, version by Gershon Kingsley but the first time I ever heard this song it was the Caustic Window (Richard D. James aka Aphex Twin) version found on the Joyrex J4 EP.
Countless versions and remixes of this song exist and I'm not going to name them all here.
Feel free to help me get a list going of the good ones or correct my very limited understand of the origins of the Hot Butter version of this song, though ...
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PHOTOSENSITIVE EPILEPSY (PSE) - SEIZURE WARNING FLICKERING IMAGES!
Just finished a write-up on this but managed to lose it somehow, so here's the short version.
Trying to write a couple of my own Triangle Fill algorithms before digging into any of the ideas presenting in this thread:
https://www.lexaloffle.com/bbs/?tid=31478
One of the algorithms I tried poorly "borrows" ideas from Brenesenham's Line Drawing Algorithm found here:
SEIZURE WARNING - FLICKERING IMAGES!
Developer Explanation
First of all love is love! Support the human rights of human beings!
This is a flicker palette expansion demo that uses 49 colors of an available 136 "colors" to animate a randomized, circular rainbow "video wipe" style effect. This is achieved by drawing two different colors on the same pixel in quick succession to dazzle your senses into tricking your brain into thinking it's seeing more colors than Pico-8 can actually draw. It looks okay at 30 fps but really benefits from 60 fps.
Apparently there is historical evidence of arcane "Super CGA" video cards using this method to expand the color palette of old 16-color monitors from a bygone era. Cool stuff. Most of the CGA cards like the CGA board that went into the IBM PC XT back then were only displaying four colors at time so there wouldn't have been much incentive to write a piece of software that actually used this technique.
This GIF image example is 30 fps since capturing a GIF at 60 fps only shows one half of the frames so the effect is lost in the conversion. This 30 fps example is also slow enough to give an idea of how the effect is achieved: each band of colors is actually three bands wide. The code runs at 60 fps which looks 100% better than the example GIF.
My goal is mostly to remind anyone who needs to hear this that Pico-8's palette can be greatly expanded using only the official 16 colors.
Just so I know my math is right the rainbow uses 7 official colors which blends into 6 new colors between the bands. The background fills with any of the 16 official color which only add 9 new colors to the mix. The red band blends with 14 of the background fill colors in a way that it hasn't already with itself and orange as does the violet band with itself and dark blue but since red blending with violet has already been counted that's only 13 additional colors for violet.
7 + 6 + 9 + 14 + 13 = 49 colors
Controls
No controls yet. It just draws sweeping rainbows until you quit. It could use some sliders to adjust things like speed, width, delays, etc.
Developer Notes
I found cart by @dw817 called "256 Colors" with Pico-8's "Lucky Draw" feature which looks to be showing at least 136 unique colors (and 120 duplicates) which was where I got the inspiration to try something similar. I had been watching videos about legacy computers and just had to try this out. It's easy to imagine how someone might have been able to get old 16-color CGA monitors to behave in a similar fashion either in software or with special hardware.
Shout out to David Murray "The 8-Bit Guy" whose video "Meet the Super CGA Cards" discusses specialized CGA video cards like the Plantronics Colorplus and the QuadColor II. I think I just figured out how the Quadcolor II supposedly has support for 136-color on 16-color displays. @dw817's cart is a literally picture of a similar set of colors using Pico-8s official 16-color palette.
For anyone interested in the history on this stuff, here's the video I'm referring to.
I highly recommend "The 8-Bit Guy" to Pico-8 developers for some insights about what 1970's and 1980's era PC gaming was actually like. Does anyone remember when the swatches in Microsoft Paint in Windows 3.1 were dithered on some systems because the hardware didn't support the colors? Nostalgia ...
This "flickering color palette expansion" method probably has to be used somewhat sparingly in practical applications because some scenes would take too long to render at a full 60 fps.
Possible Expansions
I haven't implemented any dithering which seems to open up quite a bit more color options. There might also be a way to flicker in an extra color layer or two for broader color depth but at a considerable cost to frame rates.
There are a ton of Rainbow-themed carts that could benefit from implementations of this technique. Well worth searching around the BBS for these carts. Lots of good stuff in there.
There's lots of little variables you can play with in the code to change how this little tech demo behaves. I think of it as a piece of parametric software but I haven't yet brought out the parameters to the GUI so this cart would benefit from that work.
Minimal effort to make some sort of useful library so people can place a rainbow wipe or other gradient anywhere on the screen might be useful to someone.
Musical Notes
There's no music but this might be a good effect for any demoscene kinds of work I might do with Pico-8's amazing synthesizer capabilities which I barely know how to leverage in code at this point but after discovering @luchak 's "RP-8" cart I need to dig deeper, awesome stuff.
Free Software
Feel free to use, optimize or expand this code in any way your see fit for example to accompany music, simulate shock waves or whatever other project you're working on if you just need to slap a flickering rainbow on something. It can easily be modified to use other colors and might look amazing with some fast dithering techniques maybe using special characters or something.
