Horde3D

That's probably more of an opinion. The fact is Python runs in some kind of VM, and there is no amount of optimizations that will outperform a compiled piece of code.



I don't know if you have any experience with ASM, but take it from me C/C++ aren't anything close to "map fairly closely". Just because it the compilers emit ASM doesn't mean they are similar.



Again, you are assuming that the C++ is poorly coded compared to the Python code. Just because the Python interpreter can optimize, doesn't mean that a well written C/C++ routine is slower because it can't be optimized much further.



I tried Python many times, but I just hate the concept of using indention to delimit blocks of code. I am however a huge fan of Lua, and scripting languages in general. Later.

Please note, that in general LUA is clearly faster than Python, that's why it is used in AAA games like Crysis. I have a factor of 5 in the back of my head.

EDIT: Check this: http://www.timestretch.com/FractalBenchmark.html

To reply to the original question: Why using LUA and Python scripts in game programming ?

Speed of development - no need to (re)compile. Both languages have easy to use and short syntax's, and are very good to develop task oriented systems, like AI agents and other sort of list oriented tasks, "rules" that tend to become very long C++ statements.

Another reason is reuse and manageability. Many studios have huge amounts of code written to do all sorts of tasks, and this code can be reused for multiple games, it is also much easier to simply swap a script than having to "digg" code, possibly breaking code or creating errors and warnings like "variable XYZ is never used".

Yet another reason, it's much easier to test and run LUA or python scripts in game editors, that run the game as a viewport DLL with pluggable behavior.

So bottom line: There are multiple advantages to using scripting languages for game development, and one big disadvantage, you do get a performance "run-time" penalty. How important that is, depends from project to project, and there are N possible solutions to boost your game performance.

http://shootout.alioth.debian.org/gp4/b ... &lang2=lua

http://shootout.alioth.debian.org/gp4/b ... ng2=luajit

Some nice language comparison.

Thanks a lot about benchmarking and showing differences clearly !
It was so much helpful !

I'm suprised to see that the JIT version of Lua actually beat C++ in one of the benchmarks on that site! (heavy floating point math)

The JIT version of python also beat C++ in one benchmark (heavy threading)

Wow, that's impressive. Just imagine if you could somehow use LuaJIT the way we use regular Lua now.

That higher level languages allow more scope for optimisation is a *fact*, well established in compiler theory.

I have been directly involved with compiler implementation, and have a lot of ASM experience (on x86, ARM and SPARC) - Believe me when I say that C very closely maps the underlying assembly. The syntax doesn't resemble ASM, but the structure does, loops are just conditionals tied to jumps, pointers are an ASM concept, all the types are matched to machine types, etc.

I am not saying that you can't tweak the C++ algorithm to perform better, I am saying that a naively written algorithm in python will be as fast or faster than a naively written algorithm in C++. Sure, by writing for the compiler you can get optimal ASM output, but a lot of programmers don't have the knowledge of compilers and ASM to do that.

Meaningful whitespace is one of my main gripes with python, but it does at least guarantee that everyone uses a consistent code format

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Tristam MacDonald - [swiftcoding]

I have been using a largely unknown, but great programming language for years now called Xblite(works with Horde3D great). It's BASIC syntax, and IMHO BASIC is far "higher" than Python when it some to "level":P It directly emits ASM (just like a C/C++ compiler), but does that make it possible for better optimization...not really. I personally would say C/C++ is a fairly high level language, and so is Python, Python just comes with a plethora of crap that you would otherwise have to implement yourself.



Well, you can say that about any compiled language. Code that runs on a VM is a little different obviously, but sure enough the VM had to come from somewhere. I was referring solely to syntax, as everything has to eventually resemble ASM. Does Python loops/conditionals not resemble C/C++/ASM/BASIC loops? Are Python types completely alien, or do the mimic types we've been using for ever?



Fair enough. But I disagree that you need a decent knowledge of ASM or the compiler to write concise/efficient code in anything other than an interpreted language like Python. To even write an algorithm faster/better than C++, wouldn't that require a very similar knowledge of the Python VM?



That was the whole reason for that right?

Nope. C is as close as you get to the metal without going to ASM (and C++ not much better). Python has garbage collection, doesn't have pointers, doesn't have declarations, doesn't use machine types... the list goes on. That the syntax resembles C++ is neither here nor there.

Compare these snippets, the first in python and the second in C++:

They both perform exactly the same operation (return a list of the squares of all items greater than 3 in a source list). However, even with the template, the C++ version still only works on one type of container, while the python version will work on any container (list, array, file, etc.). The C++ version is also 8 lines instead of 1, and is harder to read and maintain. But the big issue here, and the main win for Python, is that the python version can be automatically and transparently parallelised across multiple threads by the VM, and the C++ version cannot.

Nope, see the above example. High level languages express 'concepts', low-level languages express 'operations'. Operations can never be handled as well by the compiler as concepts.

This is the reason why Google wrote their backend in Python, Yahoo wrote theirs in LISP, Apple uses Objective-C for all their stuff, etc. You can't really write stuff like Google's distributed map-reduce search algorithm in a low-level language like C++. And even if you do, the performance wont be any better, and the maintainability will suck.

Quite likely.

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Tristam MacDonald - [swiftcoding]

I just came across two new native-compilation systems for Lua and Python:
http://code.google.com/p/llvm-lua/
http://code.google.com/p/py2llvm/

Is it possible to add some tutorials about binding Lua, JIT versions and "HOW TO INTEGRATE THEM" to the game on the wiki

Lua Bindings for C functions are easy to create. You can check the Horde Lua Bindings in the editor if you want to know how to create them.

PLEASE ADD SOME TUTORIALS ABOUT COMPILING LUA AND ... WITH MINGW

I don't think you understand how this whole "open source" thing works... Most of us have full-time jobs - Volker's contributions to the Horde project are entirely voluntary, so yelling at him with demands for help with things that are, frankly, not even related to horde is rather rude.

Have you read this page: http://lua-users.org/wiki/BuildingLua?