tank movement simulation

[elio]

so, here's a 'little' code which drives some tanks around in 2d, it is not related to warzone besides it leant to warzone's own movement code and perhaps if it's mature enough it'll make it in the game.

here are some screenshots for those wo can't compile source code
i use codeblocks as ide, so .cbp is the project file.
i suggest to play around with main.c (escpecially where the tanks are initialised) and the constants in simulation.c

i made no cleanup and it has hardly any commentary xD

enjoy

[elio]

there are several bottlenecks in my code, i never used sqrt but cos / sin a lot.

this is what i found
http://gruntthepeon.free.fr/ssemath/

it is not as exact as the posix version but a lot faster

I chose to write them in pure SSE1+MMX so that they run on the pentium III of your grand mother, and also on my brave athlon-xp, since thoses beast are not SSE2 aware. Intel AMath showed me that the performance gain for using SSE2 for that purpose was not large enough (10%) to consider providing an SSE2 version (but it can be done very quickly).

benching sinf .. -> 3.2 millions of vector evaluations/second -> 142 cycles/value on a 1830MHz computer
benching cosf .. -> 3.2 millions of vector evaluations/second -> 142 cycles/value on a 1830MHz computer

benching sin_ps .. -> 18.1 millions of vector evaluations/second -> 25 cycles/value on a 1830MHz computer
benching cos_ps .. -> 18.2 millions of vector evaluations/second -> 25 cycles/value on a 1830MHz computer

[EvilGuru]

Performance wise there should be no need for a special/dedicated library.

The C standard math functions (-lm) are usually very well optimised and as of GCC 4.3 can be auto-vectorised (-ftree-vectorized) assuming your loops are written well. (GCC will auto-emit SSE/SSE2/SSE3/SSSE3/3dNow/MMX code depending on your compiler switches.) If you find yourself doing a lot of vector math, however, I highly recommend you take a look at Eigen (http://eigen.tuxfamily.org/index.php?title=Main_Page ) which is one of the fastest vector/matrix math libraries going. It is C++, which may or may not be an issue, however, is very well written and performs spectacularly.

Neat application (currently toying around with adding more tanks).

[elio]

it's just a header file:

sse_mathfun.h source code for sin_ps, cos_ps, sincos_ps, exp_ps, log_ps, as straight C. http://gruntthepeon.free.fr/ssemath/sse_mathfun.h

oh i just saw this awesome collection of "Steering Behaviors For Autonomous Characters" http://www.red3d.com/cwr/steer/
awesome, i'll take a look if i can implement these concepts. there is a library http://opensteer.sourceforge.net/ but it's c++ and - a library^^

[elio]

update!

ok, now it has a tank avoidance algorithm implemented, according to http://www.red3d.com/cwr/steer/Unaligned.html
i wrote it from scratch, because i didn't want to dig around in c++ (OpenSteer)

it works at least with two tanks, hmm but has some bugs, but development goes in the right direction xD

[qwerty800]

I would much more refer to this

[elio]

my algorithm is not pathfindig, it's after pathfinding, tank should avoid other tanks, drive backward etc..