Bullet Vector Math Lib

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    • Bullet Vector Math Lib

      I am trying to use the Vector math library in Bullet, but before I write any code I want to ask a couple of questions.

      Why does it seem like Bullet's Linear Algebra library does not use the vector Library? Or am I just not seeing it?

      Should I use bt<insert-type-here> or vector/matrix(from the vector math lib) as class member variables?

      I see that both use inline declarations and appears they also use SIMD/sse instructions, am I right? If so, which one is more efficient(performance wise)?
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    • RE: Bullet Vector Math Lib

      Regarding your performance question I haven't done the comparisons myself, but I found this forum post interesting:

      bulletphysics.org/Bullet/phpBB3/viewtopic.php?f=6&t=1548

      Also - it's early in the morning here so excuse me if I don't quite understand your question about the vector Library...which vector library do you mean? There are many to choose from.
      Mr.Mike
      Author, Programmer, Brewer, Patriot
    • RE: Bullet Vector Math Lib

      I haven't looked at any of the performance metrics either, but my advice is to use one thing across your entire engine and to hide it behind an abstraction layer so you can easily change it. If you decide to use this library, make sure you have an easy way to swap it for another library if you find some fatal flaw in it. I once worked in an engine (BigWorld) that tightly couple their vector code to Direct3D's vector. That means that switching over to OpenGL would have been a pain as all of those vectors would have to be converted.

      I'm not sure how experienced you are with math, but one idea might be to write your own math library. That's what I did a number of years ago and it helped me learn quite a bit about matrix & vector operations, which is an area I was pretty weak at for a while.

      -Rez