ksassnowski (u/ksassnowski)

ksassnowski commented on Ask HN: What are you working on? (March 2025) · Posted by u/david927

ksassnowski · 5 months ago

I've been working (on and off) on part 2 of my blog post series on the rigid body collisions [0] for over a year now. I burned out on it a few times and got super mega stuck on one particular section for months on end. I think I've finally broken through the worst of my writer's block, so there might be light at the end of the tunnel!

[0]: https://www.sassnow.ski/rigid-body-collisions/1

ksassnowski commented on My son (9 yrs old) used plain JavaScript to make a game, and wants your feedback armaansahni.com/game/... · Posted by u/veesahni

ksassnowski · 9 months ago

Most of my feedback has already been mentioned by others (charging indicators, seeing what the enemy is "thinking", etc.). I still feel the urge to comment just to say how cool this is.

The sprites being animated was definitely not something I expected. Makes the whole thing feel a lot more alive all of a sudden.

I encourage everyone to also read the accompanying blog post linked in the OP. The paragraph about how I'm probably thinking that AI wrote the game for him really made me chuckle. That's exactly what I was thinking when I first read the blog title! Granted, it still would have been cool for a 9-year old, just not as cool as the alternative. So great job in immediately addressing this in the introduction. That seems like a really good use-case for AI (and I'm generally not the biggest fan of AI).

The "Dad's comments" throughout the post are also a great way of providing some additional context without editorializing the kid's own writing.

ksassnowski commented on Procrastination and the fear of not being good enough swapnilchauhan.com/blog/p... · Posted by u/swapxstar

ksassnowski · 10 months ago

This resonates so much with me. I’ve even written a blog post a few years ago with almost the same title[0].

It hasn’t really gotten better since then even though I’ve built even more cool stuff since then (hell, I even was #1 on HN for a whole day earlier this year).

[0]: https://www.kai-sassnowski.com/post/never-good-enough/

ksassnowski commented on 2D Rigid Body Collision Resolution sassnow.ski/rigid-body-co... · Posted by u/atan2

aDyslecticCrow · a year ago

Making a 2d rigid-body physics engine is a really fun project. I made one myself in javascript before learning about linear algebra. And I dug deep into the maths to get it working. Despite months of work, I barely scratched the surface beyond the widely known basics.

Making a stable engine where objects don't compress into one another or jitter is a rabbit hole without a bottom that even the most math-heavy articles I could find rarely touched.

I used a series of old articles by Christ Hecker to understand the maths myself. http://www.chrishecker.com/Rigid_Body_Dynamics

ksassnowski · a year ago

Yes! "Part 3: Collision Response" is basically what I'm using as a reference for these articles.

ksassnowski commented on 2D Rigid Body Collision Resolution sassnow.ski/rigid-body-co... · Posted by u/atan2

smusamashah · a year ago

The way this article is written with small simulations throughout the page and word highlights was reminding me of https://ciechanow.ski/ and then I noticed the domain name. It is very similar too https://www.sassnow.ski/

Couldn't be happier seeing more people going to same depths (or heights) to explain things to people. Will be looking forward to more articles like this as this just the very first one.

ksassnowski · a year ago

Bartosz was definitely my biggest inspiration when writing this post. I was debating if I should actually use that domain because it might come across as a little too derivative but I couldn't resist!

ksassnowski commented on 2D Rigid Body Collision Resolution sassnow.ski/rigid-body-co... · Posted by u/atan2

wiz21c · a year ago

It's a really good explanantion !

Pardon my curiosity, but what tools did you use to build that page ?

ksassnowski · a year ago

Thanks!

Most of the physics-based example are written in WebGL using three.js. Using three.js is a little bit overkill for this because all the examples are in 2D but it's what I was familiar with. For the actual physics simulations, I'm using matter.js.

The diagrams use a library I wrote while working on the post [1].

Everything runs inside a Vue app which serves as the glue between things like the sliders and the three.js scenes and diagrams.

[1] https://ksassnowski.github.io/vueclid-docs/

ksassnowski commented on 2D Rigid Body Collision Resolution sassnow.ski/rigid-body-co... · Posted by u/atan2

ksassnowski · a year ago

Hey everyone, author here!

To give some context, this is only part one in a series of blog posts I plan on writing about rigid body physics.

The post is aimed at people like myself, who aren't game devs and don't necessarily have a strong math background. Which is why I spend so much time explaining concepts that would appear almost trivial to someone who has experience in this area.

Happy to answer any questions you might have.

u/ksassnowski

KarmaCake day128March 18, 2017View Original