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# IGK Conference - Our Slides
Mon
28
Mar 2011
8th Polish Game Engineering Conference (VIII Ogólnopolska Konferencja Inżynierii Gier Komputerowych) IGK-8'2011 is over so now we can publish slides from our presentation:
Tworzenie wydajnego kodu c++ w podejściu zorientowanym na dane (PDF)
It's in Polish. Here is abstract of the paper:
(Polish) Artykuł opisuje wady programowania obiektowego – zarówno od strony projektowej, jak i ze względu na wydajność kodu. Porusza problem opóźnienia w dostępie do pamięci RAM we współczesnych architekturach komputerowych. Przedstawia programowanie zorientowane na dane (ang. DOD – Data-Oriented Design) jako alternatywne podejście do projektowania i implementowania silnika gry kładące nacisk na optymalizację struktur danych pod kątem szybkości. Porusza także problem wydajności poszczególnych konstrukcji języka C++.
(English) Paper describes pitfalls of object-oriented programming – from the design perspective, as well as regarding code performance. It mentions problem of latency in accessing data in RAM memory on today computer architectures. It shows DOD (Data-Oriented Design) as an alternative approach to design and implementation of a game engine focused on optimizing data structures in terms of performance. It also describes efficiency of different C++ language constructs.
Comments | #events #teaching #warsztat #igk #c++ #optimization Share
# IGK'8-2011 - 8th Polish Game Engineering Conference
Fri
25
Mar 2011
In just an hour we're leaving for this year's 8th Polish Game Engineering Conference (VIII Ogólnopolska Konferencja Inżynierii Gier Komputerowych) - IGK-8'2011 in Siedlce, Poland. As always, I will last 3 days and include lectures, as well as a competition where we have to make a game in 7 hours in teams of 4 developers. This time me and Tomasz Dąbrowski are giving a lecture entitled "Developing Efficient C++ Code with Data-Oriented Design" (Polish: "Tworzenie wydajnego kodu C++ w podejściu zorientowanym na dane"). We also plan to participate in the competition as team "Rzeźnicy Inc.", just like in the previous year. We will have access to the Internet there, so watch this forum topic for some updates and photos. See you in Siedlce!
Comments | #warsztat #igk #events Share
# Static C++ Code Analysis with PVS-Studio
Sat
12
Mar 2011
By the courtesy of its authors, I have a chance to evaluate PVS-Studio - a static code analyzer for C, C++ and C++0x. This commercial application is installed as a plugin in Visual Studio 2005/2008/2010. Fortunately I have Visual Studio 2008 Professional at home so I could try it with the code of my personal projects. PVS-Studio differs from other tools of this kind, like free Cppcheck, by finding three types of errors or warnings: general, related to OpenMP and 64-bit portability issues.
After opening my solution in Visual Studio, I choose a command from the special menu to analyze all the code.
A progressbar appears while PVS-Studio does the computations, utilizing almost 100% of all 4 CPU cores. Finally, a dockable panel appears with a list of found issues.
The general category warns about exact float comparison with == and stuff like that. It managed to find few places where I forgot the "&" character while passing a vector as const refefence parameter, rightly telling that it will cause "decreased performance". But its greatest find in my CommonLib library code was this unbelievable bug:
Some messages look funny. Should I code some general, abstract, portable, object-oriented, Alexandrescu-style template-based solution here just to avoid copying some code into several similar instructions? :)
I didn't check how the OpenMP validation works because I don't currently use this extension. As for 64-bit compatibility issues, I have lots of them - just because my code is not prepared to be compiled as 64-bit. PVS-Studio seem to do a good job pointing to places where fixed-length 32-bit integers are mixed with pointers, array indexing etc.
Overall, PVS-Studio looks like a good tool for C++ programmers who care about the quality of their code. Finding issues related to OpenMP and 64-bit compatibility can be something of a great value, if only you need such features.
Too bad that PVS-Studio, opposite to Cppcheck, is a Visual Studio plugin, not a standalone application, so it obviously requires you to have a commercial MSVS version and do not work with Express edition. But this is understandable - if you need OpenMP or 64-bit, you probably already use Visual Studio Professional or higher.
PVS-Studio analyzes C, C++ and C++0x. It doesn't work with C++/CLI language, but that's not a big flaw too. I use C++/CLI at work, but I can see it's quite unpopular, niche language. Its compilation or analysis would also be very difficult because it mixes all features from both native C++ and .NET. Even Microsoft didn't find resources to implement IntelliSense for C++/CLI in Visual Studio 2010.
Comments | #tools #c++ #software engineering #visual studio #pvs-studio Share
# Visual Studio 2010 Service Pack 1 Released Yesterday
Fri
11
Mar 2011
Yesterday Microsoft publicly released Visual Studio 2010 Service Pack 1. It is big (1.48 GB) and the installation takes quite long. It applies to all Visual Studio 2010 versions and components, including C++ Express, C# Express etc. Here is the list of changes and here is download link (you can find link to ISO file with offline installer at the bottom of that page). There are lots of fixes and improvements, but most of them apply to managed or web technologies like Silverlight. What's interesting for a C++ programmer is the addition of intrinsics to enable the extensions on the AMD and Intel new microprocessors that will be released next year - Intel AVX and AMD Bulldozer. Microsoft also claims to optimize and fix C++ compiler. Changelist mentions fixing lots of IDE crashes, including incompatibility with AMD CodeAnalyst.
Overall I think the new SP1 for VS2010 is worth installing, unless you have "Windows SDK for Windows 7 and .NET Framework 4" installed in your system. In that case an unsolved issue would happen so you should NOT install the Service Pack.
By the way: MSDN Library - the extensive documentation of C, C++, WinAPI, OpenGL, .NET and lots of other technologies - is available for free in form of an offline application for some time, but the latest version is MSDN Library for Visual Studio 2008 SP1. Do you know how to download some newer release? Or maybe that "Windows SDK" ships with it?
Comments | #c++ #visual studio #windows Share
# GDC 2011 Tag Cloud
Thu
03
Mar 2011
Today I made a tag cloud of words form titles and descriptions of GDC 2011.
To do it, I Entered the GDC website, session list, clicked on "export complete list" button and exported list to CSV file format. Next I imported the CSV file in OpenOffice Calc spreadsheet, deleted all columns except name (for the first cloud) or name and overview (for the second cloud). Then I exported this data to a CSV file again, opened in in a text editor, made all text lower-case and deleted some common words like CANCELLED using Find & Replace. Finally I pasted this text to Wordle script to create tag clouds and tweaked some parameters.
# Bit Tricks with Modulo
Sat
26
Feb 2011
I like to emphasize that programming is not so similar to maths as some people say. We are used to thinking about numbers in decimal numeral system and the operations that seem most natural for us are arithmetic computations like additions, multiplication and division. On the other hand, computer works with numbers stored in binary system and bitwise operations are most efficient and natural for it. Another difference is modulo operation (the remainder after division) - a function not so frequently used in math classes, but very important in programming. That's what I'd like to talk about here.
Modulo in C++ can be done using % operator, but just as division, it is quite slow. So when doing a common operation of cycling between subsequent numbers from a limited range:
x2 = (x1 + 1) % n;
few alternatives have been developed for some special cases, using bitwise operations.
First, when the divisor is a power of 2, we can use bitwise and (operator &) to mask only least significant bits of the addition result. But this optimization can be done automatically by the compiler (at least my Visual C++ 2010).
// 7 = 0b111, so it masks 3 least significant bits.
// Equal to (x1 + 1) % 8
x2 = (x1 + 1) & 7;
When we only cycle between two values - 0 and 1 - we can use XOR (operator ^):
// Equal to (x1 + 1) % 2, for values 0, 1.
x2 = x1 ^ 1;
Finally, when we cycle between three values - 0, 1, 2 (like when indexing x, y, z components of a 3D vector), we can use the trick invented by Christer Ericson (at the end of the linked page). I came across it recently on Twitter and that's what inspired me to write this article.
// Equal to (x1 + 1) % 3, for values 0, 1, 2.
x2 = (1 << x1) & 3;
Comments | #math #c++ #algorithms Share
# Automated Level Design Compo
Thu
24
Feb 2011
Last week an unusual competition took place on Warsztat, called Automated Level Design Compo (link to the forum thread, in Polish). Krzysiek K. coded a program that loads voxel maps in his text file format, renders them and allows to actually play such voxel games, including collision, physics and collecting some 3D models placed in the virtual world. Our task, as compo participants, was to code a small console program that takes random seed number and destination file name as its parameters and generates such voxel map. The theme for this edition was "flying islands". Here are some links related to this event:
I posted my entry and took 3rd place out of 5. Coding a voxel map generator was fun, because hacking with some math and being able to immediately see its visual results is one of the best things for someone fascinated in games and graphics programming, next to seeing your code running efficiently :) I took a screenshot from each compo entry. Mine is the 3rd one - the one with the forest (player's task on my map is to collect all mushrooms). Voxel technology is interesting. That's also why I play Minecraft a bit recently :)
Comments | #events #voxels #warsztat #competitions Share
# Naprawiacz nazw plików - My Little Tool
Fri
18
Feb 2011
Here I publish a small C# program that I developed for some specific needs of my father, but some of you may also find useful. It recursively searches selected directory for files and subdirectiores which names are too long or contain some non-ANSI characters, especially Russian cyryclic or Polish diacritic letters. It then presents the list and lets you manually rename or delete selected items, as well as automatically rename all selected items to convert these special letters to their English transcription.
This program can be useful if you collect some ebooks or other documents and need to store, pack or catalog these files in some way that doesn't like long names or nonstandard characters. The whole GUI is in Polish. The program requires .NET Framework 4. Source code in C# is attached. I think this code can be good entry point to write other similar programs that look for files and directories that meet some specific criteria.
Download:
Naprawiacz_nazw_plikow_bin.zip (EXE file)
Naprawiacz_nazw_plikow_src.zip (C# source code)
Now the Polish version:
Chciałbym opublikować mały program w C#, który napisałem dla specyficznych potrzeb mojego taty, ale może okazać się przydatny także innym. Program rekurencyjnie przeszukuje wskazany katalog w poszukiwaniu plików i podkatalogów, których nazwy są zbyt długie lub zawierają znaki spoza zakresu ANSI, szczególnie cyrylicę i polskie znaki diakrytyczne. Następnie prezentuje listę, na której można ręcznie zmieniać nazwy i usuwać wybrane elementy, a także automatycznie zmienić nazwy wszystkich zaznaczonych elementów konwertując te zestawy liter na ich transkrypcje po angielsku.
Ten program może się przydać, jeśli zbierasz ebooki czy inne dokumenty, a chcesz je zapisywać, pakować czy katalogować za pomocą takich programów, które nie radzą sobie ze zbyt długimi nazwami albo niestandardowymi znakami. Interfejs programu jest w języku polskim. Program wymaga zainstalowanego .NET Framework 4. Do archiwum dołączam kod źródłowy w C#. Myślę, że ten kod może być dobrym punktem wyjścia do pisania innych podobnych programów, które wyszukują pliki i katalogi spełniające podane kryteria.