Quake II: Physics

[n00k1e]

Here we have few major things explained by n00k1e, please read the article.

http://dl.dropbox.com/u/35665758/Quake%20II%20Physics.pdf

[Whirlingdervish]

pretty cool.

A lot of that stuff is not well understood by the people who still make q2 maps, so props on bringing it to light.

[fdrjk]

Awesome. 

That sort of explains how you were able to make the YA jump in rdm2 by just jumping up against it. Time to do some research. 

[n00k1e]

Awesome. 

That sort of explains how you were able to make the YA jump in rdm2 by just jumping up against it. Time to do some research. 

yes, it was exactly that

[fdrjk]

Was it 90 or 500 to do that jump? I think you were lying. 

[Jay Dolan]

Interesting.  He doesn't explain why this happens, tho.  It all has to do with floating point numbers and Quake's limited network precision.  But anyway.. cool read

[Paril]

Interesting.  He doesn't explain why this happens, tho.  It all has to do with floating point numbers and Quake's limited network precision.  But anyway.. cool read

That's a part of it; all the precision issues do is add a "snap" to the movement, causing your movements to drift towards a specific direction (essentially also multiplied by your cl_maxfps). The rest of the issues are caused by FPS-dependent physics.

-P

[QwazyWabbit]

Paril probably knows more about Q2 physics than most of us because he's experimented more with it and accomplished more in his "real" physics code but I didn't think the zero point was any kind of attractor at all. I suspect most of the physics bugs or tricks stem mostly from the math and precision properties of floats and perhaps some bugs in the vector math since things like push/pull and splatter seem to have preferential directions when calculating things like reciprocal directions and normals depending on your position in relation to the space origin. I have never delved much into the game physics myself to see why certain things happen. Q2 physics calls C runtime functions that calculate in float or double and return double that's cast to float so the precision and rounding can take some pretty wild rides and I don't think the designers cared about doing the algorithms in the exact order required to minimize any errors, nor do I think they did any unit tests of the physics functions to see they returned proper values under all input conditions. All of it adds splendor and fun to the game and makes it a game rather than real life.

[reaper]

nice, best movement by mistake??

[kren.Z]

n00ki1e, great observations, great thinking and great research on your part. Inform us on anything new that you look in to (even if it's not related to q2). You have a pretty good theory from a non-developers point of view. It's always interesting to hear from Qwazzy, jdolan and paril on technical details.











P.S. I'm horny

[[BTF]Defiant!]

I'm unable to read the document correctly, is there another format?

I tried Adobe Reader and several online PDF viewers.

[n00k1e]

I'm unable to read the document correctly, is there another format?

I tried Adobe Reader and several online PDF viewers.

maybe look for "online pdf viewer" in google
i.e. http://view.samurajdata.se/

[The Happy Friar]

I use FoxIT on on my wife's & my computers w/o any issues.

[[BTF]Defiant!]

After none of the suggestions worked, I redownloaded the file and found that my previous was somehow corrupted.  Works now,  thanks for the suggestions.