25 November 2015

Don't Repeat Yourself

Something that I've been working with the Planetside 2 team lately has been a more strategic direction in how we write maintainable code for the future. Part of my direction for this has been adherence to the D.R.Y. principle--Don't Repeat Yourself. Namely, instead of distributing authority out by the expression of Interfaces (and writing a lot of repetitive code), we are architecting unambiguously authoritative systems that can handle all functionality in a common way.

One of our most recent realizations of this principle is in our new UI data-source layer.

Previously, Planetside 2 (and previous Forgelight Engine ancestors) had a concept of a DataSource interface. This was a simple interface that allowed sub-systems (such as Skills or Items) to express data in a string-based row/column format to the UI layer (Planetside 2 uses Scaleform GFx, a Flash-based interpreter/renderer). The Actionscript 3 UI code could find a DataSource by name and query it in the ways expressed by the interface (it could also register as a listener to determine if anything changed).
class IUIDataSourceTable {
    virtual int GetData(int row, int column, String& output) = 0;
    virtual int GetRowCount() = 0;
    virtual int GetColumnCount() = 0;
    virtual String GetColumnName(int column) = 0;
    virtual void AddListener(IUIListener*) = 0;
    virtual void RemoveListener(IUIListener*) = 0;
    virtual void NotifyChanges() = 0;

Seems great so far, right?

Because this is an interface, each system is responsible for surfacing internal data to the UI through the GetData call. But each system can implement it completely different. As long as 'output' receives the value of a given cell, where that data comes from isn't important to the UI layer. Also, detecting when that data changed (and notifying listeners) became the responsibility of each system.

Okay... So?

Well, now let's say that you want to do more complex operations with that data, such as sorting, filtering or joining with another IUIDataSourceTable. Sure we could add additional functions to the IUIDataSourceTable, but as our codebase grows, we're faced with a quandary: how do shrinking development teams maintain ever-growing codebases??

Let's look at it a different way. Say I wanted to add a Filter function to my IUIDataSourceTable. Planetside 2 has on the order of about 130 implementations of this interface (give or take) in very disparate systems such as Character Select, Skills, Items, Marketplace, Social, Experience, etc. If I want to add another function to my interface, I'm looking at actually writing 130 functions and doing a lot of research into those systems to find out how they actually surface the data.

This is the problem with distributed authority: it exponentially extends a simple change. Work-arounds in the past involving just two things that we always want to do--filtering and sorting--required either a C++ engineer to add to a specific DataSource implementation, or a UI engineer to gather everything and sort it in Actionscript 3. This is not a very productive or sustainable model and it's ridiculously time intensive (both on the CPU and in development time).

Ok, now let's adopt a don't-repeat-yourself strategy.

Instead of declaring an Interface that each system must adhere to, let's design a system that is unambiguously authoritative in terms of UI data. We want one system that we can tune and add functionality to. And since we're talking about UI datasources, can you think of anything that is designed to store row/column data and has sorting and filtering capabilities? Maybe... like... a database?! Turns out there is such a beast that we can use as the core of our new authoritative UI data system: sqlite3! This gives us a light-weight, in-memory SQL database that we can use to store our data and slice it any way we need! And better yet, browsers (and even mobile devices) have been using it for years!

After getting an engineer excited about this prospect and putting her on the project, she turned out an awesome system called uiDB that exposed game data to the Flash-based UI through SQL and tables. This has some really cool features:

  • Adding new functionality is trivial. We just added some very broad functionality in less than a day because we changed one authoritative system instead of 130 interface implementations.
  • sqlite has a callback mechanism, so we can use Actionscript 3's event mechanism to notify the UI when data changes--automatically. C++ just updates the game data in the uiDB system as it changes, and the authoritative uiDB system notifies any listeners. No extra code required.
  • The AS3 code can create a view to slice, sort, filter, or join data however it wants and can still get notified when any of that data changes. Without having to write any additional C++ code.
  • The AS3 code can also perform any SQL query on the in-memory UI database whenever it wants. Need data one time? No problem. Need to display data and refresh when it changes? Equally trivial.
  • We wrote a DataProvider implementation for uiDB tables and views. This is the standard DataProvider that Flash widgets use, so our UI engineers don't have to write any code to handle change events or anything--the DataProvider can do all of that and the UI just updates automatically. Talk about code reduction! 
Another surprise out of changing from the interface to authoritative model is that our UI data performance increased, even though we were now using a SQL-interpreting database! This is because of a few different reasons:
  • In the Interface model, each system retrieved its data through different means. Some could be woefully inefficient.
  • sqlite3 is a well-tested, highly optimized, tightly-packed, small C library. It has a development team that cares only about its performance and functionality in a variety of settings. As such, we are gaining the wealth of knowledge and experience of another team focusing intently on one piece of technology, allowing us to focus on making a game. (This could branch into another discussion about utilizing as much third-party technology as makes sense).
  • By consolidating authority in one system instead of spreading it out, we had one target to focus on for performance testing and optimization.
We are continuing to provide additional functionality through this system to our UI engineers in order to make their lives easier (and we're doing this across the board for all disciplines). This is looking forward to the future of Daybreak Games and the Forgelight Engine as much as the future of Planetside2.

All in all, work smarter, save time across the board, and don't repeat yourself!

30 June 2014

By the Library of Thor!

I recently uploaded to github a C++ template library called Thor, which is something that I've been playing around with. It's really just a way for me to write some crazy template code--a creative outlet if you will. This blog post is meant to show off some of the things that I'm proud of in Thor. The name Thor came in part because of inspiration from Andrei Alexandrescu's template library Loki and his book Modern C++ Design (an excellent advanced C++ book).

Some things in my Thor library are just me implementing things in the way I would if I had full control, and some are a slightly different take on popular concepts. Some things are already outmoded based on offerings in C++11 (especially in terms of atomic support), but are included for posterity.

I apologize that the code samples are images (Blogger currently doesn't do well with template syntax), but generally a link is provided to the code on github.


The C++ standard library includes several standard, well-known and well-documented containers, however these containers don't often allow for much customization. For instance, std::vector (up until the C++11 standard) had no obvious means to free memory (C++11 adds the shrink_to_fit() function). Although not technically correct, I'll refer to the C++ standard library as STL below for brevity's sake.


Thor's string class works very similarly to std::string and std::wstring with a few changes. First, the strings are atomically reference counted, so the underlying string data is shared when possible. Secondly, a template parameter can be specified to pre-reserve (as part of the basic_string instance, not a separate heap allocation) space for the string. The default of zero is a fully dynamic string, but if you need a quick string on the stack and don't want to allocate anything from the heap, it is easily done with the addition of a size template paramter:

Furthermore, in addition the STL constructors for basic_string, additional options are available for printf-style formatting and literal strings (that don't require copying or allocation):

The printf-style formatting is also supported for append, insert, replace and assign variants.

Thor's string also supports conversion between UTF-8 and "wide" (wchar_t). If wchar_t is 32-bits, then the conversion will be between UTF-8 and UTF-32, however the more likely case is that wchar_t is 16-bits, in which case the conversion will be between UTF-8 and UTF-16, complete with support for UTF-16 surrogate pairs.


In general node-based STL containers (such as std::list) will allocate a 'dead node' or a terminator node from the heap as soon as they're constructed (even default constructed). Usually this terminator node will include space for the 'T' stored type, although that space will never be used and therefore wastes space. I frown upon the fact that wasted space is allocated from the slower heap for such a simple operation as default constructing a list.

Consider Thor's list class. Instead of heap-allocating a terminator node, the head/tail pointers for the list class use a list_node_base and the address of the list_node_base is used as the terminator. Thus, the terminator (used by the end() iterator) is implemented as such:

This has the advantage of not requiring a heap allocation for the terminator node while still allowing for simple reverse iteration and no need for null-pointer checking at head/tail. However, there are two disadvantages. The first is that any accidental writes to the end() iterator (which is completely invalid anyways) may cause memory corruption. This can be prevented in checked/debug builds with asserts when trying to dereference the end() iterator. The second is that swap semantics require slightly more finesse (although these are more complicated in Thor for another reason explained below). In std::list the swap() function must only exchange pointers and counts between two lists--since the terminator node is allocated on the heap it is not tied to either list and is automatically part of the swap. However, since Thor's list essentially has a local terminator node as part of the instance, care must be taken to fix up the terminators during swap:

Notice that the swap function handles a concept of shareable. This is because of another enhancement of Thor's containers. Essentially, space for a certain number of items can be pre-allocated along with the container, similarly to the string class mentioned above. For instance, thor::list<T,5> specifies that no heap allocations must occur for the first five list entries. Fortunately, thor::list<T,5> inherits from thor::list<T> so that it can be used anywhere where a list is required. However, it also means that the problem of swap() now must handle pre-allocated nodes. It is less efficient to swap() a list with pre-allocated nodes as this requires the nodes be converted to heap allocated nodes.

There are many other extensions to all of the containers, yet they all try to remain true to the C++ standard library specification.

thor::hash_map (et al)

The thor::hashtable class (which forms the basis of hash_map, hash_set and the multi- versions of each) has a noteworthy feature: a policy class that controls how the stored values are organized into buckets. The options are a power-of-two system that is very fast by using bitwise masks instead of divide/mod instructions (although this method can be terrible for pointers as keys as they typically are multiples of 4 or 8 and the bucket strategy loses efficiency leading to collisions), or a more traditional (and slower yet less collision-prone) prime-number strategy.

The C++ standard library hash containers are undefined order containers. This means that the order in which you insert items is not necessarily the same order in which you would iterate over the items. However, thor's hash containers are a fusion of a list and a hashtable, which allows for a defined iteration order as well as amortized O(1) lookup time. This does require a slight change to how iteration starts: the begin() function defaults to 'list' iteration mode but can be changed to 'hash' iteration mode, whereas find() operations default to 'hash' iteration mode.

Embedded Containers

For std::list (or thor::list for that matter), the 'T' type that you're storing in the container is contained within a node that tracks other information for the container. If you had a list of pointers to objects in the heap, then the objects were allocated and the list container must allocate a small node to store the pointer. This is wasteful. The embedded containers can alleviate this by having the node tracking information as part of the object that is being stored. For instance, the 'T' type stored in a thor::embedded_list must contain an embedded_list_link member and the member is given as a template parameter to thor::embedded_list.

Atomic integer/pointer

The thor::atomic_integer system is similar to C++11's atomic wrapper, so while not completely necessary it was a fun exercise to write. The real meat of how it works is based in the platform-specific interlocked system (the Windows version is interlocked_win). This uses template specialization to handle one-, two-, four- and eight-byte integers. By using intrinsics, these atomic_integers actually compile down to very few inline instructions for most operations. Consider how declaring interlocked works on a platform with a 32-bit integer. First, some magic happens based on how the non-specialized interlocked class is declared. There is a second template parameter that is required, but defaults to sizeof(T):

The template parameter T_SIZE defaults to 4 for int, which causes a specialization to be selected:

This specialization uses the correct functions/intrinsics for the numeric type that we're wrapping in atomic_integer. This allows atomic_integer to do the correct operation based on size of the integer parameter:

Memory Alignment

Another place where Thor uses template specialization is with memory alignment. All of the containers do memory allocation through Thor's memory functions. There is a simple class called the align_selector:

This class's only job is to determine if an object can use system-guaranteed alignment or not (most objects can). If the system alignment will suffice, alignment_selector::alignment will be zero. The align_alloc class uses the align_selector as a default template parameter to select the proper specialization for the alignment:

The system default alignment just allocates raw bytes:

But the default version that handles non-default alignments will over-allocate and offset:

Arguably, this version could use _aligned_malloc or memalign or similar, but by using new[] an application may still override new and use their own memory manager if so desired.

There is a lot more to the Thor library. Take a look at it on github and let me know what you think.

15 May 2014

Busting Mines

Behold: Bust A Mine. My first iOS development project.

Not a bad run!


When I set out to (once again) try my hand at iOS development, I didn't know what the future would hold. It was around the time that a former game that I worked on, Clone Wars Adventures, had announced that it would be ending on 31 March 2014. One of my favorite mini-games in CWA was called Mine Buster, a simple game that involved creating a chain reaction for points. It was also a mini-game that would soon cease to exist. And a good mini-game that could use a Spiritual Successor.


I started working on my own rendition in early March while professionally employed as the Director of Technology at Molten Games. Within two weeks of late-night spare time I had a working prototype that functioned similarly to its inspiration. I had heard good things about using Cocos2D 3.0 and it seemed to fit the bill. My prototype was still very rough and could only run on the iOS Simulator that comes with Xcode 5. However, I was happy enough with the progress that I decided to spring for the iOS Developer Program so that I could actually run and debug on my iPhone and iPad. There was a little learning curve to overcome as running code on the device requires creating App Identifiers, Certificates for code signing and Provisioning Profiles for signed code to be allowed to run on the device. Being able to run and debug on my devices was instantly gratifying, but also revealed another issue: the need to deal with different screen sizes (iPad vs. iPhone) and aspect ratios.

Artist Wanted

It was time to start finalizing the art--getting real assets at the necessary sizes and building out the art style. For this, I'd actually need an artist. Fortunately, Molten's UI artist was on-board with the project after seeing the prototype running on my phone. He had free reign with the art style and created a look inspired by the likes of Geometry Wars yet unique in its own right. We worked together to integrate the art into the game and iterate on the style. Unfortunately, Molten Games collapsed around this time, towards the end of March. Priorities shifted to finding a new day job since this project was a journey of Experience and less of Business.

To Test or not to Test

Working with an artist brought to light another need that I'd have to figure out: distributing test builds of my app to other people. For this I began using Test Flight. This provided a great way to bring testers on board and get feedback. The only issue was minor: when a new device was registered, I would have to add the device's unique identifier to the provisioning profile and upload another build of the app. I started acquiring testers with a broad spectrum of devices. I also acquired a few devices of my own: non-Retina iPad and older iPhone. I was also blessed with winning an iPad Mini in a contest! I made sure to also test on the newer 64-bit devices. Through this I actually discovered some 64-bit compatibility issues with Cocos2D 3.0 (in beta at the time) and worked with the developers to solve them.

Sprechen Sie Deutsche?

I can understand exactly one of these.
Having visited Moscow and Shanghai for assisting Planetside 2 localization (and working on games for the past decade or so), I'm constantly reminded of the worldwide gaming community. The English-speaking community might be easier for me to market, but it's a small part of the world. Therefore, I wanted to make sure that my app could be distributed and popular in other locales. I had a very small number of strings (less than 100), so professional localization would be fairly easy. I originally started working with Rev.com but found them difficult and obtuse. I ended up going with e2f and found them slightly more expensive, but very easy to work with. They appreciated all of my contextual notes and turned around six languages (French, Italian, German, Spanish, Russian and Simplified Chinese) in less than 24 hours. In hindsight, I should have included a few more items in the translations, such as future (generic) update notes and anything that I would potentially need in the next few months.

Finishing Touches

This game, since it was an exploration of experience, was going to be free and advertisement-supported. However, given the ease of doing in-app purchases, I would offer an in-app purchase to remove the ads. I also wanted GameKit integration to essentially have free Leaderboards. Fortunately many kind developers have written simple APIs around these pieces of functionality and have shared them for free. Integrating the likes of ABGameKitHelper and MKStoreKit was very easily done. My testers also suggesting graphical features such as using UIMotionEffect to simulate a parallax display on iOS 7+.

A Different Beat

Having some manner of background music was important to me. However, I'm not a composer. I don't really know many composers. So I started looking for free music. Interestingly, though, "free" isn't always free. Some companies let you use their music for free for certain purposes, and an app is not generally one of those free uses. I originally wanted to use some songs from Freeplay Music, but after seeing their licensing requirements and reading about their litigation processes, I decided against it. I ended up using music by Chris Zabriskie who offers his music for free with a Creative Commons Attribution license. I feel that his music meshes well with the peaceful, soothing nature of Bust A Mine's laid-back gameplay.

Pre-Launch Checklist

I've heard of using a test market to pre-launch, so I figured I'd give that a try. I have some friends with family in the Philippines and it seems to be a fairly popular test market. Launching in the Philippines also revealed an interesting fact: iAd isn't available in all parts of the world. Therefore, my advertisement strategy would have to change for a worldwide launch.

3... 2... 1... Liftoff!

Bust A Mine officially launched in a limited capacity on 9 May 2014, about 9 weeks after development started. Considering that it was my first foray into iOS development and Objective-C programming in general, I'm calling that a success. Not a business success, but an experiential success. For the full worldwide launch, I'm waiting for Apple to approve the next version that will integrate Google AdMob as a backup to iAd.

To Infinity and Beyond

The background reverberates with explosive force
I really enjoy iOS development. The Objective-C language allows for easy checking to see if features are available on the device it's running on. Furthermore, the Xcode integration with Apple back-end services is very well done and easy to use. Want GameKit integration? Flip a switch and you've got it.

Several people have asked about an Android port as well. Interestingly, no one has asked about a Windows phone version. In any case, I'm considering a port to Cocos2D-X, a C++ library that supports all major mobile platforms.

I've got plenty of ideas for Bust A Mine for the future. And a few of my game designer friends have offered some feedback and ideas of their own. Plus, I have more ideas for future games as well. Mobile development has become a fun little hobby for me.

Download Bust A Mine and give it a try. Leave a review or rating if you feel so inclined. And let me know what you think in the comments!

04 February 2014


I just created a repository on github.


For a while I've been writing a json parser (fully RFC-4627 compliant) similar in interface to rapidxml as a fun way to write some simple code that ended up being fairly complex. I mean, there's a good bit of template partial specialization in there, exception/non-exception handling, Unicode support, unit-testing, etc.

It even figures out if you've given it UTF-8, UTF-16 or UTF-32 and whether the endianness matches your machine or not.

Yeah, so that's how I have fun. Enjoy, universe!

21 November 2013

Catching Fire

Well, it happened.

Nearly two months ago I took the plunge and left Sony Online Entertainment to be the Director of Technology at Molten Games. Molten is a small but well-funded and growing start-up in the San Diego area.

I. Am. Having. A. Blast.

We're building a rock-star team and making a great game. I can't wait until I can talk about it, but you're going to have to stay tuned for a bit.

08 January 2013

Getting Ripped

For the past few weeks I've been converting my DVD and Blu-ray Disc (BD) collection to MP4 format so everything can be easily viewed on the Apple TV. Generally, this has been fairly painless (especially for DVDs), but there is one thing that I desire that most people probably don't care about: captions.

Maybe I'm getting old, but for about a decade I've preferred to watch shows with captions. There are basically three types of captions present on DVD and BD media:

  1. Closed Captions - text-based captions that may include hard-of-hearing information.
  2. Bitmap Captions - bitmaps that are overlaid on the screen.
  3. Forced Bitmap Captions - technically a subset of (2). Typically shown for foreign languages.
Bitmap Captions allow the DVD/BD publisher to ensure that captions look the same on every player, whereas text-based Closed Captions can look and perform differently on different players, TVs, etc. And in my experience, Bitmap Captions don't display on the Apple TV whereas Closed Captions will. Also of note is that DVD and BD each use a separate type of Bitmap Captions--VobSub for DVD and PGS for BD.

Now, if Bitmap Captions don't show on the Apple TV, why do I care about them? There are two main reasons: 1). If Closed Captions don't exist and 2). Forced Subtitles.

At this point I should mention that I'm using Handbrake to encode my movies for the Apple TV. Several pages exist as guides to using Handbrake, so I'm not going to cover it in much detail, except for dealing with captions.

If Closed Captions Don't Exist

If a DVD has Bitmap Captions (VobSub) but no Closed Caption, then we need to find a way to add text-based Closed Captions. Fortunately, there are a few options.

The first option is my least favorite. Handbrake has the ability to burn-in Bitmap Captions. This means that captions will be present, but there will be no way to turn them off. For all captions, that's not desirable, but as seen below it can be quite handy for Forced Captions.

The second option is to find a SubRipper (SRT) file that someone has created. Fortunately there are some great crowd-sourced resources for this, like Open Subtitles and my personal favorite, SubScene. These sites allow you to search for a SRT file that someone has created and uploaded. Handbrake can import the SRT file by using the Import SRT button (seen in the picture above). The downside to this method is that timing is everything. There can be Special Editions and Director's Cut versions of the movie you're searching for, so ensuring that you have the correct file will involve using Handbrake's Preview feature or using a player (like VLC Media Player) to preview before encoding. Otherwise you could end up with captions that don't match.

The final option is to create your own SRT file from the Bitmap Caption. This can either be done manually (VERY time consuming) or with the aid of OCR software. This was more of a last resort for me, but I did do it for a few of my DVDs. I used a program called Subresync. It is about as naive as OCR software can be, essentially asking the user the first time it encounters a specific pixel pattern:

Forced Captions

This is where things get a bit trickier. Forced captions were typically not a problem for DVDs as all of my DVDs that used Forced Captions actually had them burned in to the video stream. Not so for my BDs. A good example is Star Trek VI: The Undiscovered Country where the Klingon speech is a Forced Caption track and is not burned in to the video stream. And Forced Captions are something that everyone should want as they are essentially part of the movie.

Also complicating this process is the fact that Handbrake does not yet understand PGS-style Bitmap Captions (the system used for BDs). Therefore, the PGS (or 'Sup') Captions must be converted to VobSub before using Handbrake. This involves the following steps:
  1. I use MakeMKV to get the BD data on the hard disk in MKV format.
  2. Load the .mkv file in the mkvmerge tool from MKVToolNix. This will tell you which tracks contain PGS Caption data:

    In this example, IDs 2, 3, 4 and 5 contain PGS subtitle data. Leave this program open as we'll come back to it if we do indeed find Forced Captions.
  3. Extract the subtitle data using mkvextract on the command line:
    mkvextract tracks Star_Trek_VI...mkv 2:sub2.sup 3:sub3.sup 4:sub4.sup 5:sub5.sup
    This will extract tracks 2-5 into files sub2.sup, sub3.sup, sub4.sup and sub5.sup
  4. Open each extracted PGS Subtitle file using BDSup2Sub to see if it contains Forced Captions. In the Star Trek 6 example, we find that track 3 contains nothing but Forced Captions:
  5. Since we've found Forced Captions, we need to convert them to a format that Handbrake understands. Fortunately, this is what BDSup2Sub was designed to do. File->Export gives the following dialog (make sure that 'Export only forced' is checked):

    Interestingly, VobSub is made up of a .idx text file and a .sub binary file.
  6. Now we need to add the newly created VobSub captions and re-mux into a new .mkv file. Go back to the mkvmerge that was open from step 2. Click the Add button and select the new .idx file that was created in step 5, then press Start Muxing:
  7. When the muxing finishes, you can now load the new .mkv file up in Handbrake and burn-in the Forced Captions:

Getting captions to work correctly on the Apple TV with custom-encoded movies can be a bit tricky, but if you're hard-of-hearing or just used to using captions, hopefully this guide can help you.

02 May 2012

New Domain!

Well, I've finally gotten around to registering joshuakriegshauser.com. It's about time. Which means that this blog will appear at blog.joshuakriegshauser.com.

Oddly enough, kriegshauser.com is considered a premium domain and is listed for about $1600. I honestly hope whoever is holding it never gets that.