bctr [Lexaloffle Blog Feed]

pico3e - 3D physics engine

Mon, 19 Aug 2019 13:41:00 UTC

PIco3e is a 3D collision engine written in PICO-8! As far with the alpha release, what it does is...

This was the alpha version, in wireframe. It does work with arbitrary rotated bodies and solve the forces correctly. It took me about 3 weeks of learning & coding, and below is the demo cart I've been using it for proof of work.

Implemented features from reference project qu3e:

3D Oriented Bounding Box (OBB) collision detection and resolution
Discrete collision detection
Collision test via the Separating Axis Theorem
Collision manifold generation via face-to-face method and the sutherland clipping

Token usage: 2873 (with current scene). Thus space is sufficient for some game logic. Unfortunately cpu usage is a bit high, with collision between each 2 bodies takes 5% cpu in 30 fps and doubled in 60 fps. Therefore it's assumed optimal number of bodies is <= 4.

v1.0.0 Known issues:

edge to face collision's force center is biased
body doesn't rotate if supporting force is aligned to mass center
cannot handle multiple body collisions / compound forces

And especially thanks so much to @freds72 without his help I couldn't make this happen.

Aug 13th, 2019. Update with a playable scene and fixed the edge to face collision bug.

Press Z to take a screenshot when the same color faces are aligned to camera.

pico3e - 3D physics engine

by bctr

[Click to Play]

alpine7000

Mon, 11 Mar 2019 09:12:39 UTC

Hi! Folks. Here's my submission for 7DRL 2019.

It's a turn-based survival game, in which you play as a mountaineer trying to reach 7000m with limited supply. For now we basically have only one type of room.

alpine7000

by bctr

[Click to Play]

galaxy_generator

Sat, 02 Feb 2019 10:55:54 UTC

Modified previous work to add a centroid bar to spiral galaxies.
https://en.wikipedia.org/wiki/Barred_spiral_galaxy

Press: "x" to regenerate.

galaxy_generator

by bctr

[Click to Play]

moon_rises

Thu, 31 Jan 2019 18:02:24 UTC

moon_rises

by bctr

[Click to Play]

Originally from Tobiasvl's tweetcart: https://twitter.com/Spug/status/1090559155436511232

(Sorry I didn't include the link before.)

Proc-gen Galaxy

Wed, 30 Jan 2019 15:41:00 UTC

Taken from a discord's discussion, algorithm provided by @ skaarjslayer: http://itinerantgames.tumblr.com/post/78592276402/a-2d-procedural-galaxy-with-c

And also reference to: https://en.wikipedia.org/wiki/Archimedean_spiral

gotunozosi

by bctr

[Click to Play]