Alf 2: Collision Detection Is Hard, Blog Posts Are Harder | Hacker News Reader

Alf 2: Collision Detection Is Hard, Blog Posts Are Harder

nicole.express

69 pointszdw9 comments

> As I noted in the prior blog post, the Sega Master System has a tilemap that’s only 256 pixels wide, the same as the display area. Therefore, the image is slightly off-center

For anyone else for whom this made no sense, the off-center image is a tradeoff to allow for smooth horizontal scrolling when the tilemap that is used as the source for the display is the same size as the available display area. This is indeed explained in this prior post linked by the author (https://nicole.express/2021/sega-system-1-system-1.html).

> ...hardware collision detection feature of the Master System. This feature triggers a flag when two sprites collide, but does not tell you which sprites collided.

I want to say... WTF!? This is kinda evil, I have no idea and I love it!

> Alf 2: Collision Detection Is Hard, Blog Posts Are Harder

I did semi-recently re-write an amazing collision detection technique I found by myself and used around 1991 (it was fast and flawless) and I even wrote some (Clojure, whatever) code to create "nice looking images" to explain visually the technique. I even started working on the blog post but...

It's not done yet so you have no idea how I agree with this title...

(part of the problem being that I haven't a blog yet. I've got some material: several things I want to write about and the name of the blog and, heck, I wrote entire books in the past so it's not as if writing was that problematic)

Hey, where can I check this blog? Im interested in collision detection in games.

Well that's the thing... I haven't published anything yet. I don't even know which blogging platform I'll use. It's on my TODO list though so.. One day.

Feels. I found my static site generator got updated in a way that wasn't backwards compatible, and it stopped being able to generate my site. The older versions of the software got pulled and I wasn't very happy with it anyway, so I've been slowly migrating to another one.

It hasn't stopped me from writing posts... Which does feel a bit odd... They're just not getting published.

I did find that kind of odd. Even the old C64 would set bits to tell you which sprites collided.

Here's the article on Part 1:

https://nicole.express/2021/remember-alf.html

A nice follow up on a very dry topic. And a well done, for a very definite improvement in communicating the results of their investigation (Red/black border issues not withstanding ;) )

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