外文翻译-解决嵌入式OPENGL能在高度嵌入和安全的环境中

1、外文原文：SOLVINGTHEEMBEDDEDOPENGLPUZZLEMAKINGSTANDARDS,TOOLS,ANDAPISWORKTOGETHERINHIGHLYEMBEDDEDANDSAFETYCRITICALENVIRONMENTSAbstract：EmbeddedgraphicalHumanMachineInterfaces(HMIs)areincreasinglymakinguseoftheOpenGLrenderingAPIasastandardfordefiningandrenderingscreengraphics.Thistrendissupportedbytheemergenceofhardwareacceleratedgraphicssubsystemsandcommerciallyavailabledriversoftware.Meanwhile,embeddedgraphicstoolandsoftwarevendorshaveadoptedOpenGLinvariousformsastherenderingAPItheysupport.Forhighlyembeddedandsafetycriticalenvironments,however,fullOpenGLisnotanarrowenoughstandard.Inordertoachievelow-cost/lowpowerhardwareimplementationsandreducedrivercomplexitytoachievesafety-criticalcertification,OpenGLsubsetsmustbeembraced.Inrecentyears,themobilegraphicsindustryhasbenefitedfromtheeffortsofindustryconsortiumstodefinecapableOpenGLsubsets.Thesesubsets,orprofiles,existinvariousversionsintendedtofacilitatethedevelopmentofapplicationsforwidelydifferingembeddedmarkets,fromcellphonegraphicstosafetycriticalhigh-poweredembeddedgraphicssubsystems.Itisclearthatsuchwell-definedstandardscanandwillhaveabeneficialimpactontheembeddedandsafety-criticalgraphicsindustries,offeringunprecedentedportabilityandsimplicityforHMIapplications.Whatisnotasclearistheleveltowhichgraphicstoolandsoftwarevendorsaresupportingthenewstandards.Thestakesarehighfortheenddeveloper,asrelianceonAPIcapabilitiesthatareeitherunsupportedordifficulttocertifycanpresentserioussystemintegrationandcertificationpitfalls.Thispaperpresentsrecommendationsinsuchareasastoolselection,standardstolevyonvendorsanddevelopers,approachesforachievinguserinterfacesandfontrenderingusingtheOpenGLstandards,andrecommendationstoensurethesuccessfulengineeringandwidedeploymentofHMIsoftware.BackgroundGraphicalProcessingUnits(GPUs)Overthepast10years,displayrenderingtechnologyforplatformembeddedsystemshasundergonefundamentalchanges.Thesechangeshavebeendrivenprimarilybytwotwintechnologicalthrustsflat-paneldisplayhardwareandadvancedraster-basedEGSsystemsusingOpenGL.Flatpanelshaveenabledanincreaseindisplayresolutionwhilestillsupportingembeddedsizeandweightconstraints.RasterbasedEGS,particularlybasedoncommodityOpenGLhardware,hasprovidedthehorsepowertodrivetheincreasedresolution.Therenderingengine,orgraphicschip,isthepartofthemobilecomputingdevicethatprocessesgraphicsandcreatesorrendersthedisplay.Onthedesktop,hardwarerenderingenginesdominate,resultingintwoseparatehighperformanceprocessorsbeingpresentinmostsystemsoneforgeneralcomputing,andoneforprocessinganddisplayinggraphics.ThedevelopmentoftheGPU,hasbeenlargelydrivenbythedesireforbettervideogamingcapability,butalsobythedesireforbetterworkstationanddesktopgraphicalprocessing.GPUtechnologyhasfoundanicheinembeddedsystems,providingadvanceddisplaycapabilitiesthatweredifficultorevenimpossibletoachieveinlegacygraphicaldisplaysystems.TheseembeddedGPUsareembeddedvariantsofdesktoporlaptopgraphicscards,featuringGPUs,onboardtexturememory,andhardwareacceleratedlighting,transformation,andrasterization.Offeringsfeaturinghardwarefrommajordesktopgraphicscompaniesarebeingwidelyusedinmilitaryapplications.AnembeddedGPUisshowninFigure1.MostGPUtechnologydeployedinembeddedsystemstodayhasitsrootsindesktoporlaptopbasedgraphicsaccelerators.PowerconsumptionfortheGPUalonecanrangefrom5to15W.Thesedesignscanprovidepowerequivalenttoadesktoporlaptopwithinanembeddedenvironment,providedthesupportingdriversoftwareisavailable.OpenGLisbyfarthemostcommonlyusedstandardtosupplythesedrivers.OpenGLasanEmbeddedStandardTheadventoftheGPUhasbeenaccompaniedbywidespreaduseofnewstandardsdesignedtofacilitatedevelopmentofgraphicalapplicationsthattakeadvantageofthehardware.OnesuchlowlevelApplicationsProgrammingInterface(API)isOpenGL.OpenGLprovidesasoftwareinterfacethatsupports2Dand3Ddefinitionofgeometryandrenderingfunctions.SomeofthemajorfunctionsOpenGLsupportsinclude:Matrix-basedgeometrytransformationsViewportandclippingregionsTexturedgeometryGraphicspipelinestatemanagementGeometrycachingThesefunctionsaresupportedthroughalogicalpipelinethattheGPUimplements.Thepipelineexpectsgeometryspecificationintheformoftriangles,points,andlines,alongwithtransformation,clipping,color,andtextureinformationusedtoconverttheintotheformrenderedintotheframebuffer.InnewerGPUs,thefixedfunctionpipelinewhichrepresentsstandardmethodsofprocessinggeometryhasbeenaugmentedwithvertexandpixelshaderoperations,whichallowmoreprogrammabilityofthepipelinefunctions.APIslikeOpenGL,alongwithotherpopularstandardssuchasMicrosoftDirect3D,providesoftwareinterfacestodrawgraphicsintheGPUpipeline.TheGPUpipelineforOpenGLisshowninFigure2,wheretheblueAPIbubbleontheleftrepresentsOpenGL.Figure2.OpenGLPipelineOpenGLisastandardizedAPIthathasevolvedovermanyyears,initiallythroughtheeffortsofgraphicsindustrypioneerSiliconGraphicsTM.Ithasachievedwidespreadadoptioninthesimulation,gaming,CAD,andprofessionalgraphicsmarkets,andisthede-factostandardforembeddedapplications.Itiswidelyavailableonmanyplatforms.OpenGLisalsomeanttoprovideastandardinterfacetomultiplegraphicsrenderingdevices,allowinganapplicationtorunwithconfidenceongraphicschipsfrommultiplevendors.Itisakeystandardintheembeddedavionicsmarketduetoitspowerandcrossplatformnature.OpenGLasanAPIhasundergonemuchgrowthinthepast15yearsorso.Asmoreclassesofapplicationssoughttoexploititscapabilities,successiveversionsofthestandardhaveevolved,bringingmorecallsandmorecomplexitytothestandard.OpenGListypicallyimplementedusingadriverarchitecture.OpenGLdriversencapsulatesalow-levelinterfacetotherenderinghardware,andpresentsahigh-levelinterfacetoapplicationsthatneedtousethehardwaresfeatures.AsOpenGLhasgrown,sohaveitsdrivers.AmodernOpenGLdriverforadesktophigh-endgraphicscardcaneasilyrunintomillionsoflinesofcode.Embeddedvariantscanbesmaller,dependingonwhatsubsetofOpenGLtheysupport.OpenGLsubsetsareakeytechnologyinthenextwaveofmobileGPUtechnology,targetedformoreintegratedmarkets.OpenGLandMobileGPUsInthelastfewyears,mobilecomputersfeaturingadvancedrenderingtechnologyusinglow-powerGPUshavebeguntoappearonthemarket.Thesedevices,targetedforcellphone,mobilegamesystems,PDAs,automotiveuses,medicaluses,andotherdeeplyembeddedapplications,arecurrentlyoneofthemajordevelopmentareasinmobiletechnology.Asmobilegamingreachesitsmarketpotential,mobiledevicemanufacturershavebeguntoaddresstheGPUintheirdevicedevelopment.OftenastandardgraphicsAPI,suchasOpenGL,istoolargeorcostlytoimplementonthesedevices,soCOTSdriveranddevicemanufacturersrelyonsubsetsoftheAPI.Thesesubsetsmanufacturerstooffercapabilitiestargetedtospecificmarkets.Applicationsmustbewrittentoworkwiththesmallersubsets,whichoftenmeanstheycannotbeportedeasilyfromonesubsetenvironmenttoanother.MobileGPUtechnologyenabledbywell-definedAPIsubsetshasledtotheemergenceofSystemOnChip(SoC)designs.InaSoCdesign,theGPUiscombinedwiththeprocessortoencapsulateacompletegeneralpurposeanddigitalmediaprocessingcoreonasinglechip.Suchadesigncanbeintegratedintoverysmall,lowcostapplicationssuchashandheldmedicalequipment,cellularphones,automotivetelematicsdisplays,etc.MobileGPUshaveanobviousapplicationinembeddedandsafety-criticalmarkets.Oftentimes,powerconsumption,weight,andsimplicityofdesignarekeyfactorsinsystemdesign,andmobileGPUtechnologywillhaveabigimpactintheseareas.AsentirelynewclassesofdevicesbegintoemergeandofferOpenGLcapabilities,thepotentialusageofOpenGLbysafety-criticalapplicationstargetingthesedevicesmustbeaddressed.RecommendationsEmbracingAPIStandardizationWhileOpenGLisagoodstandardforsafetycriticalsystemsandshouldbeused,ithasgrownlargeasanAPI.StandardizedsubsetsprovideakeytousingOpenGLinthesafety-criticalanddeeplyembeddedenvironments.TheOpenGLESstandardbytheKhronosGroupisanimportantdevelopmentinstandardizedspecialpurposesubsetsofOpenGL.KhronosisanindustryconsortiumdesignedtofostertheadoptionofOpenGLintoembeddedandmultimediamarkets.Khronosissupportedbyallmajorgraphicschipmanufacturers,mobilephonemanufacturers,andthemobilesoftwaredevelopmentcommunity.OpenGLESisawell-definedsubsetofOpenGLthatisdesignedtoprovideacapablesubsetforadvancedgraphicsondemandingembeddedplatforms,includingmobiledeviceswhileeliminatingredundantcapabilityandstressingsimplicityandsmallfootprint.SincethefullOpenGLspecificationislargeandgraphicssubsystemsthatsupportthefullspecareresourceintensive,awell-definedsubsetisrequiredtoprovideatargetrenderingcapabilityforembeddedapplications.OpenGLESisthatsubset.entirelynewclassesofdevicesbegintoemergeandofferOpenGLcapabilities,thepotentialusageofOpenGLbysafety-criticalapplicationstargetingthesedevicesmustbeaddressed.RecommendationsEmbracingAPIStandardizationWhileOpenGLisagoodstandardforsafetycriticalsystemsandshouldbeused,ithasgrownlargeasanAPI.StandardizedsubsetsprovideakeytousingOpenGLinthesafety-criticalanddeeplyembeddedenvironments.TheOpenGLESstandardbytheKhronosGroupisanimportantdevelopmentinstandardizedspecialpurposesubsetsofOpenGL.KhronosisanindustryconsortiumdesignedtofostertheadoptionofOpenGLintoembeddedandmultimediamarkets.Khronosissupportedbyallmajorgraphicschipmanufacturers,mobilephonemanufacturers,andthemobilesoftwaredevelopmentcommunity.OpenGLESisawell-definedsubsetofOpenGLthatisdesignedtoprovideacapablesubsetforadvancedgraphicsondemandingembeddedplatforms,includingmobiledeviceswhileeliminatingredundantcapabilityandstressingsimplicityandsmallfootprint.SincethefullOpenGLspecificationislargeandgraphicssubsystemsthatsupportthefullspecareresourceintensive,awell-definedsubsetisrequiredtoprovideatargetrenderingcapabilityforembeddedapplications.OpenGLESisthatsubset.ToolsandAPIsOpenGLgraphicsdeveloperstypicallyemployseveralstrategiestosuccessfullycreatetheOpenGLsoftwaretodrawscreens,includingtool-baseddevelopmentandhand-code.Bothapproachescanmakeuseofsoftwaremodularity,encapsulatinghigherlevelinterfaces,suchasadigitalmaplibrary,userinterfacelibrary,orfontrenderinglibraryintoSDKsforreuseinthesystem.ThesetoolsandSDKsmaymakeassumptionsaboutsupportedfeaturesoftheunderlyingOpenGLdriverandgraphicshardware.Ifagoaloftheapplicationistobeportabletoenvironmentswheredrivercapabilitymaybelimited,theseassumptionswillalmostcertainlyneedtobechallenged.Manytoolsoperateusingcodegenerationtogeneratecoderepresentingadisplaydefinition.Displaydefinitionsareenteredintoauserinterface,andthetoolthenemployscodegenerationtocreateOpenGLsoftwareimplementingthedisplay3.SuchOpenGLsoftwarecanencompasstensorevenhundredsofthousandsoflinesofcode,mostofitdevotedtogeometryspecification.UsefulnessofthiscodeforallOpenGLenvironmentsmaybelimitedunlessitscodegenerationisflexibleenoughtotakeintoaccountallOpenGLsubsetstheoutputmightneedtosupport.ThecodegenerationapproachisillustratedinFigure4.Inadditiontotooloutputlimitingflexibility,ifareusableOpenGLlibraryhasbeenwrittentorelyoncertainconstructs,suchasOpenGLdisplaylistsorthestandardglBegin-glEndparadigm,itwillnotbeusefulonplatformswherethedriverdoesnotsupportthisparadigm.Therearesometechnicalapproachesthatcanbeconsideredtoalleviatesomeoftheseproblems.ConclusionsEmbeddedOpenGLisakeytechnologythathasbeenandwillcontinuetobeusedonsafety-criticalembeddedsystems.GPUtechnologyborrowedfromthedesktopandworkstationmarketshaslargelybeenusedfortheseapplications.TheadventofnewembeddedchipsetsemployingOpenGLwillincreasethisusageandpotentiallyextenditintonewareaswherecost,power,andweightbarriersarebeingbrokendown.InordertotakeadvantageofOpenGLinalltheseapplicationareas,thewidespreadusageofOpenGLsubsetspresentsaprogrammingandintegrationchallenge.Subsets,suchastheOpenGLESSafety-CriticalprofilefromtheKhronosgroup,representeffortstostandardizeOpenGLandprovideacommonsubsetapplicationscanrelyon.SoftwareapproachestohandlingdifferingOpenGLsubsetscanbeemployed,buttheseapproachescansufferperformanceandcomplexityissues.AmoreflexibleapproachistoconsidergeometryspecificationasdataTheresultoffailingtopayattentiontoOpenGLanditssubsetscanbecostlyforasafety-criticalapplicationdevelopment.WhenportabilitytodifferingOpenGLenvironmentsisdesired,ortheabilitytoemploylowcostSoCormobilerenderingGPUsisneeded,theOpenGLstrategymustberigorouslyscrutinizedtoensuresuchportabilitycanbeachieved.Thealternativeiscostlyreworkoftheapplicationtoaddressdifferingstandards.02、外文资料翻译译文：解决嵌入式OPENGL能在高度嵌入和安全的环境中摘要在支持新的标准的水平是不清晰的。对于终端开发者来说，这些要求是非常高的，就像既不支持或很难的保证的API的可靠性。这篇论文在对厂商和开发者征税方面提出了些建议，获得用户接口和用OPENGL标准来确保工程的成功作为定义和表现屏幕图象来说，嵌入式的HMIS正在使用OpenGL来表现API.由于图形加速子系统和商业驱动的出现，这一趋势能被很好的支持。同时，嵌入的图形工具和软件厂商已经在他们的API中支持OpenGL。因为其高度的嵌入和关键的安全环境，完整的OpenGL不是一个狭窄的标准。为了能获得低价格/低功耗的硬件设备和减少获得关键安全证书的驱动的复杂性，必须包含OpenGL的子集。近些年，移动图形工业已经从定义合适的OpenGL子集的工业联盟的努力中获得利益。这些子集，或外形,存在于趋向为广泛的不同的嵌入式市场的应用的不同版本提供服务。它很清楚如此定义明确的标准罐子和将会有一种在嵌入式和关键安全的图形业上的有益的影响，提供空前的便携和简单的HMI程序.图形工具和软件厂商正和HMI软件的广泛调度的建议。背景图形处理单元（GPUs）在过去10年内,嵌入式的系统经历了基本的变化的平台显示技术。这些变化已经主要被两个相似技术所控制，使用了OPENGL的显示硬件和高级的以光栅为基础的EGS系统。平面显示已经在支持嵌入式尺寸和宽度限制方面有了很大的提高。以光栅为基础的EGS已经在解决增强的方法方面提供了足够的马力，特别是建立在日常的OPENGL硬件上。那些渲染引擎或图形芯片是处理图形和创建或渲染图形的移动处理设备的一部分。在桌面系统方面，硬件渲染引擎起处于统治地位，导致了两个高性能的处理器的分离，这两个处理器目前存在于大部分的系统中。一个是一般计算，一个是处理和显示图形。GPU的发展已经在很大程度上被较好的游戏能力和好1的工作站和桌面图形处理的需求所控制。GPU技术在嵌入式系统中寻得了一片生存空间，能提供在高级的在线的显示系统中很难或不可能达到的显示能力。这些嵌入式的GPU被嵌入到不同的桌面式的图形卡片中，是GPU的特征：随身携带的存储器，硬件加速光设备，转换设备，光栅设备。大型的桌面式图形公司提供有特色的硬件，在军事方面得到了广泛的使用。一个嵌入式的GPU如下：图1GPU图例目前大部分的GPU技术被用到嵌入式的系统中，它已经在桌面式图形加速方面占据一席之地。对于GPU有个大胆的设想：将其功耗限制在515瓦。这些设计在嵌入式的环境中能提供一个相等的功耗给桌面式或手提式的设备，并能提供一个可用的软件驱动程序。OpenGL是目前大部分的共同的标准所提供的驱动程序。作为一个嵌入式标准的OpenGLGPU的出现是伴随着那些新设计的标准而出现的，这些新设计的标准的出现是为了适应能充分利用硬件优势的图形程序的发展。OpenGL是一个比较底层的应用程序接口，能提供支持2D和3D的几何绘图的函数的软件接口。一些主要的OpenGL所支持的头文件如下：几何矩阵变换视口和裁剪变换纹理变换图形传递途径状态的管理几何变换缓存2这些函数得到了能被GPU执行的逻辑的传递途径所支持。这个传递途径在三角形、点、线和变换、裁剪颜色、纹理信息方面期望有一个几何规范，这些三角形、点、线和变换、裁剪颜色、纹理信息通常被用来转换几何图形，使这些几何图形能变成一种绘图模式存于帧缓存中。在较新的GPU中，那些代表标准几何图形处理的固定的函数传递途径已经增强了顶点和像素明暗的操作,能允许更多传递途径函数的可编程性。应用程序接口同OpenGL类似，是伴随着其它流行的标准而发展起来的，比如MircrosoftDirect3D,能在GPU传递途径方面提供可以画图的软件接口。OpenGL是一个经过多年发展的标准的应用程序接口，最初是通过图形工业先锋.图2OpenGL框架SiliconGraphicsTM的努力。在模拟、游戏、计算机辅助制造和专业图形处理市场方面，已经获得了广泛的应用。此外它还成为嵌入式应用的事实上的标准，在许多平台上是非常有用的。OpenGL还打算提供一个标准接口到多图形绘图设备上，允许一个应用能伴随着厂商在图形芯片的信心而运行。OpenGL能在嵌入式电子设备市场上成为一个关键的标准，主要归功于其超强的处理能力和跨平台的的特性。作为一个应用程序接口，OpenGL经历了15年的发展。当更多的应用去扩展能力途径时，OpenGL的经成功版本的发行，给这个标准带来了更多的需要3和更多的复杂性。OpenGL是一个典型的用驱动体系结构来执行的。OpenGL给绘图设备封装了一个底层接口，给那些需要使用硬件特性的应用程序提供一个高级的接口。当OpenGL在发展时，它的驱动程序也随着发展。为一个桌面式高级的终端图形硬件提供的现代OpenGL驱动使其能轻松地运行上百万条的直线的代码。嵌入式变量之所以能变得越来越小，主要得益于OpenGL的子集的划分。OpenGL子集在下一个移动GPU技术的浪潮中是一个关键的技术。它的目标是更多的集成芯片市场。OpenGL和移动的GPU在最近几年，一些具有高级绘图技术和低功耗的GPU的移动计算机开始在市场上出现。这些设备是目前移动技术的一个主要的发展领域，它们的目标是单个的电话、移动游戏系统、PDA、汽车行业、医药行业以及其他的深入的嵌入式的应用。当移动游戏发掘出其潜在的市场时，移动设备制造商开始从事GPU驱动程序的开发。通常一个标准的图形应用程序接口，太大或太昂贵而不能在这些设备上得到应用，比如OpenGL，所以检测设备驱