Development and Debugging Tools for Windows Phone 7 Series Cullen Waters Software Development Engineer II Advanced Technology Group, Microsoft Corporation

Who Should Stay for This Talk? Game Developers working on other mobile platforms interested in branching out to mobile Folks who have not used XNA professionally

Who Might Want to Leave? who have shipped an XNA XBLA title People who are uninterested in Windows Phone 7 Series development Game Developers

Toolset Silverlight 3 (plus) XNA Visual Studio 2010 Visual Phone Developer Express Single, integrated download

Silverlight 3 (Plus) Silverlight 3 with some device-specific additions Accelerometer Touch Location

XNA Framework 4.0 A new version of XNA Full 3D support on the device APIs similar to those we know and love from Windows and Xbox 360

Visual Studio 2010  Full debugging support on the device  Lots of new goodness in Visual Studio 2010

Visual Studio &.NET  Productive development with.NET & C#  High performance IDE  Intellisense makes coding faster  Integrated build/deploy/debug experience  MSBuild engine for build automation

Visual Phone Developer Express New Express SKU for Visual Studio 2010 Supports Silverlight and XNA development Full device debugging support

Windows Phone 7 Series Emulator Supports full application development Reduces costs of test and development Emulator, not a simulator

XNA Project System  C# is the only language for XNA development for Windows Phone 7 Series  All code files are organized into.csproj project files .csproj is an MSBuild-based project system

XNA Content Pipeline Simplify Your Content Usage! Provides build-time modification of source content Customizable, extensible Runs only on Windows Full.NET support p/invoke Managed C++, VB.Net, IronPython, and so on

Content Pipeline Project Changes  Makes for easier parallel development of art and code  Content pipeline is extremely extensible, so integration with existing tools is possible  Content projects no longer appear as child projects of the game project

There are lots of great tools out there, both free and commercial These are my “must-have” tools

Explore, browse, and analyze.NET assemblies Understand relationships between classes Verify code obfuscation.NET Reflector

MSIL disassembler Useful for seeing what code is being generated at build time ildasm

Also known as F1 profiler Performs code performance profiling, using sampling or instrumentation Visual Studio Team System Profiler

Sampling vs. Instrumentation  Sampling takes samples at regular intervals  Generally better for initial investigation  Instrumentation inserts probes into the code  Use for more targeted profiling

Profiles managed memory usage Invaluable for debugging game memory management CLR Profiler

Pix for Windows Graphics debugger GPU performance investigation Semi-transparent view into DirectX 3D Shader debugging Ships with DX SDK

FxCop Static code analysis tool Integrated into Visual Studio Analyzes compiled code Not all rules will likely apply to games

Code Obfuscation  All un-obfuscated code is open source  Dotfuscator Community Edition bundled with Visual Studio

Obfuscation

Wait a Minute!  Most of those tools are Windows tools  I’m developing a game for Windows Phone 7 Series!  How do those tools apply to development for Windows Phone 7 Series?

Debugging NetCF Titles Cross-Platform Solution Develop on Windows Profile on Windows Deploy to Device

Getting Info from the Device  Roll your own on-device tools  Visual information, from the game  Check out Ito’s debugging toolset

Timing on the Phone  No high-precision timer  ≈ 1 ms resolution  How do you get accurate timings from that?  Capture multiple frames of data and calculate an average  Multiple 0 or 1 values, averaged over a bunch of frames, gives you a pretty accurate result  FPS component from Shawn Hargreaves

Heightmap Collision Sample

Build and Run on Windows  Frame rate is good  Iteration time is wonderful  Life is good, ship it™!

But Then We Run on a NetCF Device  Frame rate is poor  Gameplay is affected by unpredictable stalls  What’s going on?  Most likely cause: Garbage collections

Sidebar: NetCF Garbage Collector  Mark and Sweep  Not generational  Halts all managed threads on the device

We’re Allocating During Gameplay?!?  Let’s figure out where  Run the game on PC, under CLR Profiler

CLR Profiler

Kill the Collector!  Remove allocations during gameplay  Pre-allocate  Be careful of hidden allocators  How could this be easier?  Run it again on the device, and we get constant frame rate

Constant FPS != Good FPS  Constant + Low == still bad  Fire up the VSTS profiler, and figure out where we’re spending our time

VSTS Profiler

Sidebar: NetCF Jitter  Non-optimizing jitter  Primarily designed for application development  Apps bound by I/O, not by CPU/GPU  High latency toleration  No inlining

There’s the Culprit!  Make changes to fix the code  Run on the device again  FPS is good, ship it™!

Wrapping It Up  Use Windows to your advantage  Keep your game running on the target platform  Design with the target platform in mind

Additional Resources      CLR Profiler download page CLR Profiler download page  Ito's debugging tools Ito's debugging tools