Wiley.Games.on.Symbian.OS.A.Handbook.for.Mobile.Development.Apr.2008 (779888), страница 76
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(Note that Symbian OS v9 does have good support foron-device debugging and code profiling in the Carbide.c++ IDE.)This can add up to an extremely cumbersome, time-consuming andcostly exercise when working on multiple platforms.Airplay System removes every one of these restrictions. It abstractsthe technical details of the native operating systems, and even details ofthose operating systems’ proprietary SDKs because the developer doesnot need to install any OS-specific SDKs in order to develop games forthose platforms. Airplay System also provides full C and C++ standardlibraries, and a full STL implementation.Because one of the supported native operating systems is Windows,the game developer can do 95 % of their game development purelywithin a familiar desktop environment.
An x86 build of the game canbe debugged within the standard desktop IDE debugger. Currently therecommended IDE is Visual C++ (VC6, VC. NET 2003 and VC 2005 areall supported), because this is widely considered to be the most advancedand efficient development environment available. It has full support forboth code and data breakpoints, edit-and-continue, and fast compilation,and most developers are already very familiar with it.The Windows implementation of the solution is designed to modelas closely as possible all aspects of the target devices, and to raiseissues within the IDE before hardware testing takes place.
For example,screen size, available heap memory, available stack memory, portrait orlandscape display, CPU/GPU load balancing of graphics pipeline andmany more parameters can all be configured and respected within theWindows implementation.However, there are certain use cases that oblige a developer to testthe game within the simulator provided by the native target platformSDK (for example, the BREW simulators), because it may be requiredby certain platforms for their certification process (for example, TRUEBREW compatibility testing). For such cases, the Airplay System solutionseamlessly integrates with the simulator so that a developer can very easilytest and debug their application within the development environment.Reducing Code DebuggingAirplay System includes a real-time ARM emulator that allows executionof the single ARM binary within an ARM debugger (which is alsoincluded). This approach uniquely provides the ability to test and debugthe exact code that will be run on a device within a desktop environment,and results in a huge increase in productivity, compared to using ondevice debugging.346AIRPLAYThe real-time ARM emulator is fully integrated with Visual C++; ifbuilding an ARM Debug configuration, the ARM emulator is launchedinstead of the Microsoft x86 debugger.
Both software rendering andOpenGL ES targets can be debugged at source-level within the ARMemulator.Performance of the ARM emulator is roughly equivalent to a 150 MHzARM 9 target device with no hardware graphics acceleration.Reducing Art Development CostsPlatform fragmentation persists not only for the native OS but also for thegraphics capabilities of the device. Addressable devices typically rangefrom ARM9 100 MHz, all the way up to ARM11 400 MHz+ with GPU.Hardware acceleration can generally be addressed through OpenGLES drivers; however, OpenGL ES is not a good choice for pure softwarerendering, and typically developers are required to develop their ownsoftware renderer if they want to achieve any kind of interactivity onlow-end devices.Developing a high-performance software renderer is a costly exercise.Even then, the developer must write two sets of render code; one toaddress their software renderer, and one to address OpenGL ES (thefuture need to address other graphics APIs such as D3D Mobile will onlymakes this situation worse).Airplay Studio solves the graphics fragmentation problem by providinga complete end-to-end tools and runtime art pipeline, which seamlesslyaddresses low-end pure software rendering devices, high-end hardwareaccelerated devices, and all capabilities in between.
The runtime providesa graphics API abstraction layer that seamlessly supports software rendering and any other graphics APIs the device may provide. It includesan optimized software renderer (over six years in development) that iswidely considered to be the best-performing software renderer in mobilegames development today.The term ‘scalable content pipeline’ sums up the following featuresand efficiencies provided by Airplay Studio:• the ability to export models, animations and materials from 3DS Maxor Maya• software rendering and OpenGL ES 1.1 from a single set of art assets• software rendering and OpenGL ES 1.1 from a single set of rendercode• the ability to down-scale high-end art assets gracefully as required forsoftware rendering; for example, automatically palletizing textures,AIRPLAY347automatically merging triangles into n-gons for software rendering,automatically tri-stripped for OpenGL ES• load-balancing between CPU and GPU, according to the maturity ofthe GPU and drivers.The final point may benefit from some explanation.
At Ideaworks3D,we have been working for several years with prototype and shippingversions of first-generation hardware-accelerated mobile devices. Wequickly learned that the OpenGL ES drivers were a critical component inthe equation when trying to maximize graphics performance. Just becausea GPU driver is compliant with the OpenGL ES specification, it doesn’tmean that all the API calls are actually accelerated by the GPU – many willbe implemented purely in software. Often these implementations are soslow that the developer, knowing the specifics of their API usage, could doa better job themselves. We found that, to ensure maximum performanceacross all flavors of devices, there are three stages of the pipeline whichneed to be switchable between the OpenGL ES drivers and an optimizedsoftware solution: transform, lighting, and rasterization. Airplay Studiouniquely provides this flexibility, therefore providing optimal graphicsperformance across all devices from a single game binary.Reducing the Cost of Deploying to New HandsetsAirplay splits the production and post-production process, by havingseparate development and deployment environments, ensuring that gamedevelopers and deployment producers can concentrate on their specifictasks alone, resulting in much higher productivity.
Airplay is designed toallow additional platforms and handsets to be added, and to allow gamesthat have already been completed to be deployed to these new platformsor handsets, without needing to rebuild the game.Support for additional platforms is added by the Ideaworks3D teamresponsible for implementing the platform abstraction APIs. These engineers are experts in the wide range of issues related to working withnew platforms, and with all the subtleties involved in ensuring compliantbehavior.Once the additional platform support has been added, an updatedversion of the solution is distributed with the new deployment target.This deployment target can be accessed via both the development anddeployment environments, and it is not necessary to rebuild any projectsin order to deploy to the new platform.
Therefore, games that have alreadybeen completed, and verified to correctly use the platform abstractionAPIs, can trivially be packaged for the new platform in the deploymentenvironment, with no input from the game development team, and thuswith negligible deployment cost.348AIRPLAYThe solution offers a threefold approach to adding support for additional handsets:• each platform implementation is designed and developed to berobust – potential device-specific issues are anticipated and as manyparameters as feasible are obtained from the device.
This results in ahigh level of compatibility without any changes needed• in order to facilitate working around device issues and limitationswithout requiring a code rebuild, the solution offers a data-drivenapproach whereby device profiles can be specified (in a text file) toset parameters to correct common behavior faults• handset manufacturers and carriers inevitably find new and excitingways to break the platform implementations on their devices, in whichcase, it may be necessary to make code changes to correct for these.
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