True Bullets?

Posted in: Velocity Raptor | May 7, 2012 | 2 Comments

Thanks to the fine folks over at the xkcd fora, I’m happy to annouce I was wrong about the bullets in Velocity Raptor. I’m even happier to announce that the ‘measured’ bullets have been fixed.

They had been drawn in a way that slanted the bullets away from their true path. Given the argument outlined in April 30th’s post, I thought this was fine. I thought, in fact, it was a demonstration of the Thomas Rotation.

But it turns out this just wasn’t the case. The error in my thought process was that I had LEFT OUT the Thomas Rotation. Two boosts added together can make a boost + rotation. I thought the rotation sprang from my code naturally. But it didn’t. I needed to add that rotation in by hand.

Look how much happier Velocity Raptor is!

So thanks to everyone who brought it to my attention. The ‘measured’ bullets are now fixed in the game. Go enjoy the (now slightly-less) trippy world of Special Relativity.


This entry was posted in Velocity Raptor. Bookmark the permalink. Follow any comments here with the RSS feed for this post. Post a comment or leave a trackback: Trackback URL.


  1. By A Random Player

    Posted May 18, 2013 at 10:27 pm | Permalink

    Ok, sorry ’bout the email (I really don’t have one :)), but this has been bothering me for quite a while. In the seen view of VR, the room shrinks/gets closer behind the raptor. But light should take longer to reach the raptor from behind him, so the view behind the raptor should be stretched out. Similarly, the view in front of the raptor’s motion should appear contracted. Where am I wrong in this?

    • By TestTubeGames

      Posted May 19, 2013 at 7:23 pm | Permalink

      That’s an excellent question — and it made me have to stop and think for a while. (That happened a lot as I made the game, as you can imagine.) I started to write up an answer, but then it got longer and longer… and needed pictures… so I decided to turn it into a new blog post. (

      I’m glad you took the time to ask the question — I know the seen view can be extremely counter-intuitive. And if I didn’t explain it well, please keep asking-away in that post’s comments.

Write your comment

Your email is never published nor shared. Required fields are marked *


You may use these HTML tags and attributes: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <s> <strike> <strong>