Bitplanes are powerful, but they can be difficult to understand. How do you use them in PICO-8?
The short version: bitplanes let you draw colors to the screen without completely overwriting the existing colors, making it possible to do effects like shadows, transparency, etc. But be warned: they come with a lot of unintuitive restrictions, like monopolizing half your screen palette or requiring it to be set up in a particular way.
Longer version: PICO-8 colors are 4-bit numbers (0-15). The screen is a 128x128 4-bit image, but you can imagine it as 4 separate 12x128 1-bit images overlaid on top of each other. By poking a particular location in memory, we can tell PICO-8 to draw to these "bit planes" separately. Normally, drawing overwrites any existing colors, but if we selectively disable some of the bitplanes, some bits of the old color will remain onscreen.
Technical version: see "Technical details" below.
This post lists some specific examples and tricks that you can do with bitplanes. I won't attempt to fully explain how bitplanes work, but I'll leave some resources at the end.
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PICO-8 supports bitplane drawing; the wiki (search "bitplane") has a description of how they work:
> 0x5f5e / 24414
> Allows PICO-8 to mask out certain bits of the input source color of drawing operations, and to write to specific bitplanes in the screen (there's 4 of them since PICO-8 uses a 4BPP display). Bits 0..3 indicate which bitplanes should be set to the new color value, while bits 4..7 indicate which input color bits to keep.
> For example, poke(0x5f5e, 0b00110111) will cause drawing operations to write to bitplanes 0, 1, and 2 only, with 0 and 1 receiving the color value bits, 2 being cleared, and 3 being unaltered.
> This formula is applied for every pixel written:
> dst_color = (dst_color & ~write_mask) | (src_color & write_mask & read_mask)
This is precise and correct, but I find it a bit hard to understand. So I made this cart to give myself an interactive sandbox where I can play around with bitplanes, to see how they affect drawing.
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Title. When I set Finder to open .p8 files in pico, it opens, but pico just hangs on a black screen.
Example Video
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Recreation of the JavaOS screensaver as seen in
https://youtu.be/yxV_pR1ZsXM?si=T757wSvjK0JbQaI2&t=1011
code has been made as small as possible while remaining highly performant. (3% cpu usage)
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Description
This cartridge simulates orbital mechanics using Newton's law of universal gravitation. It is recommended to experiment with the settings, which can be found in the code. The planets are generated randomly, so try reloading the cart to find interesting combinations.
Camera Controls
By default, the camera will follow the average of the planets' positions, giving you a view of all the planets. Use the Z key to lock on to a specific planet, and keep pressing Z to cycle through different planets. Pressing the X key will let you move the camera manually with the arrows or WASD, and pressing it again will go back to the automatic camera.
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Having a hard time figuring out how to get a pico eight running on my RG405M with gamma OS. Anyone done this yet?
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pov youre playing a celeste mod that hasnt removed screen shake
@Infinite86 yes. yes we can.
slightly less cursed version where the current screen shake amount is added to the next and shake decreases a lot faster
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A game I made with the help of Lazy Devs Academy tutorial on youtube
controls:
arrows to move
x to fire
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! IMPORTANT !
It appears this might be a Windows specific solution, in order to launch it in the 3:1 aspect ratio it is intended for, you either have to type the following into a command line, have it in a batch file or as the target on a Windows Shortcut:
"cd C:\Program Files (x86) (*) \PICO-8\pico8.exe -displays_x 3 -displays_y 1"
(*) Part before star symbol dependent on your install location.
You cannot play the game on here (screen is limited to 1/3rd) and I sadly do not have a Linux machine to test out alternatives. You can play it straight from your browser at the itch.io page.
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Hello,
I'm playing around with a Le Potato, which is very similar to a Raspberry Pi 3b. I downloaded the RPi version of P8 and tried to run it on the Le Potato (running Raspbian 11), but nothing happens. No error, nothing. No execution at all.
Am I doing something wrong? Or is it just not supported on this hardware?
Thanks!
Stobe
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Isocraft
Controls
Arrow Keys - Horizontal Movement
E and D - Vertical Movement
S - Place or destroy selected block
F - Open or close Block Menu
Z - Debug Menu (Coordinates and Name of Block)
X (Hold) - Quit
Description
This game is a very stripped down version of Minecraft, removing everything that is not essential to get to the very core: building. There are no mobs, no survival, not even a player character. Instead you are given 9 blocks, a 20x20x10 area and a few songs to listen to while you create.
Creator's Comment
While it might not be an impressive length for others, this is my first project I've finished after working on it for over a week. I've always struggled with staying on one project for even more than a few days. I came really close to achieving this with my last project, "Ashes", but burnt out at the very tail end of development. For finally achieving this feat, I'd like to thank some of my friends for showing interest in this project and helping me with ideas/bug fixes, especially "Luigi" (not his real name).
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