《真实感光照效果》PPT课件

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1、真实感图形建模与绘制第二讲真实感光照模型视相关绘制方法2GlobalIlluminationExtendstheLocalIlluminationModeltoinclude:Reflection(oneobjectinanother)Refraction(Snell’sLaw)Transparency(bettermodel)Shadows(atpoint,checkeachlightsource)Antialiasing(usuallymeanssupersampling)3Wireframeviewofatestsce

2、ne.Orthographicviewfromabove4Locallyilluminatedtestscene.Ambienttermonly5Locallyilluminatedtestscene.Phongshading.AmbientandDiffusetermsonly6Locallyilluminatedtestscene.Phongshading.Ambient,diffuseandSpecularterms.Notes:Highlightonwallfromlightisinthewrongplace7Com

3、parison.FlatGouraudPhongCoarsermesh8UseLocalillumination.No.Inourtestscene,wecan’trepresent:MirrorChrometeapot.ShinyfloorShadowswithlocalillumination.9TestScene.Highqualityrenderingoftestscene.Note:Mirrorandchrometeapot.Shadowsonfloor.Shinyfloor.10Globalilluminatio

4、n.Twomethods:Viewdependentmethods.Calculatetheviewfromthecamerawithglobalillumination.Recursiveray-tracing.Viewindependentmethods.Solvelightingfortheentirescene.Radiositysolution.11Viewdependentmethods.Looproundthepixels…..Goodforlightingeffectswhichhaveastrongdepe

5、ndenceonviewlocation:Specularhighlights.Reflectionsfromcurvedsurfaces.Onlyasmallnumberofobjectsneedtobeconsideredatthesametime.PoorwhenmanyobjectsneedtobeconsideredE.gdiffuseinteractions(eg.colourbleeding).12Viewindependentmethods.Looproundthescene…Goodwhenmany(all

6、)objectsneedtobeconsideredatsametime.Diffuseinter-reflections.Poorwhenshadinghasstrongdependenceonviewlocation.Specularreflection.真实感图形建模与绘制视相关绘制方法14Ray-Tracing:WhyUseIt?SimulateraysoflightProducesnaturallightingeffectsRay-tracingeasiertoimplementFall201115Ray-Trac

7、ing:WhyUseIt?SimulateraysoflightProducesnaturallightingeffectsReflectionFall201116Ray-Tracing:WhyUseIt?Refraction,causticsFall201117Ray-Tracing:WhyUseIt?SimulateraysoflightProducesnaturallightingeffectsSoftshadowsFall201118Ray-Tracing:WhyUseIt?SimulateraysoflightPr

8、oducesnaturallightingeffectsdepthoffield,motionblur19Whitted模型特点：整体光照模型的典型代表；与光线跟踪技术密不可分；考虑了光源在物体表面的直接照射产生的光亮度，同时还考虑了环境光在镜面反射方向和规则透射方向对被照射点产生的光能贡