《Unity虚拟现实技术及其应用》 课件 6 render-pipeline-game-engine

Material,Shader,Texture

材质，着色器，纹理Material:definehowasurfaceshouldberendered.TheavailableoptionsforamaterialdependonwhichShadertheMaterialisusing.Shader:scriptsthatcontainalgorithmsforcalculatingthecolorofeachpixel,basedonlightinginputandthematerialconfiguration.Texture:bitmapimages.AMaterialcancontainreferencestotextures.MaterialAMaterialcanbeconsideredacollectionofelementsthatproducetherenderingeffects.Importantproperties:

color,

texture,

shader创建Material

MaterialProperties

（对应StandardShader）RenderingMode:Opaque,Cutout,Transparent,Fade.AlbedoColorandTransparencyAlbedoparametercontrolsthebasecolorofthesurface.ThealphavalueoftheAlbedocolorcontrolsthetransparencylevelforthematerial.将材质添加到游戏对象Codingformaterials//Createsamaterialfromshaderandtexturereferences.

Shader

shader;Texturetexture;Colorcolor;voidStart(){Rendererrend=GetComponent<Renderer>();

rend.material=newMaterial(shader);

rend.material.mainTexture=texture;

rend.material.color=color;}MaterialnewMat=Resources.Load("DEV_Orange",typeof(Material))asMaterial;gameObject.GetComponent<Renderer>().material=newMat;UsingcolorspublicclassExample:MonoBehaviour{ColorcolorStart=Color.red;ColorcolorEnd=Color.green;floatduration=1.0f;Rendererrend;voidStart(){rend=GetComponent<Renderer>();}voidUpdate(){floatlerp=Mathf.PingPong(Time.time,duration)/duration;rend.material.color=Color.Lerp(colorStart,colorEnd,lerp);}}Parametersoftextures纹理形状(TextureShape)：2D，缺省下为2D，用于大多数情形下。所有的图片都作为2D纹理处理，用于3D网格的纹理映射。纹理大小(Dimensionsize)：纹理的长和宽应满足2的n次方(2、4、8、…、1024、2048pixels)等等。要注意的是，给定平台能支持的最大纹理大小是有规定的，同时，Unity允许导入的最大纹理为8k，即8192x8192pixels。Unity也支持非2n大小的纹理，但需要更多的内存和计算量进行取样处理，所以尽量将纹理处理为2n要求的大小。重复或拼接模式(Wrapmode)：Repeat，重复模式，将贴图重复平铺到物体表面。Clamp，强制拉伸，将纹理拉伸以覆盖物理表面。UsingTexturesOperatingtextureswithcodespublicclassExampleClass:MonoBehaviour

{publicTexture[]textures;publicfloatchangeInterval=0.33F;publicRendererrend;

voidStart(){rend=GetComponent<Renderer>();}

voidUpdate(){if(textures.Length==0)return;

intindex=Mathf.FloorToInt(Time.time/changeInterval);index=index%textures.Length;rend.material.mainTexture=textures[index];}}MeshFilter&MeshRendererTheMeshFilter

takesameshfromyourassets

andpassesittothemeshrendererforrendering

onthescreen.ToseetheMeshinyourscene,youshouldaddaMeshRenderertotheGameObject.MeshAmeshcontainsverticesandtrianglearraysofaGameObject.Twoimportantproperties:verticestrianglesThetrianglearraysaresimplyindicesintothevertexarrays;threeindicesforeachtriangle.MeshFilterAclasstoaccessthemeshofagameobject.Properties:mesh,gameObject,transform,name,MeshRendererAclasstorenderthemeshofagameobject.Properties:material,gameObject,transform,name,drawatrianglevoidStart(){Vector3[]vs=newVector3[3];vs[0]=newVector3(0,0,0);vs[2]=newVector3(1,0,0);vs[1]=newVector3(0,1,0);int[]ts=newint[3];ts[0]=0;ts[1]=1;ts[2]=2;///左手Meshmesh=newMesh();GetComponent<MeshFilter>().mesh=mesh;mesh.vertices=vs;mesh.triangles=ts;}021createandrenderatrianglegameobject,

onlyusingC#codesWriteC#codes,createandrenderageometry014230,3,1,0,1,2,0,2,3,4,1,3,4,2,1,4,3,2MaterialAMaterialcanbeconsideredacollectionofelementsthatproducetherenderingeffects.Importantproperties:

color,

texture,

shader创建Material

将材质添加到游戏对象利用EditorC#RenderingPipeline（渲染管线）DongfengLiuSchoolofInformationEngineeringGuangdongUniversityofTechnologyGuangzhou,ChinaOutline

计算机图形技术：3Dworldto2Dimage;三个步骤：变换（transform），模型变换、视点变换和投影变换裁剪，剔除位于裁剪面之外的物体视口变换，上述变换后的坐标与屏幕像素之间建立对应关系。

geometricalinformation—图元RenderingPipelineCoordinatesystemsinUnity

ZYX1.坐标系统对象坐标系(objectcoordinatesystem:OCS)x,y,z世界坐标系(worldcoordinatesystem:WCS)X,Y,Z相机坐标系(viewingcoordinatesystem:VCS)n,u,v（n的方向是从视点指向center的方向）投影坐标系(clippingcoordinatesystem:CCS)X,Y,Z(规格化设备坐标系，坐标值-1~1之间)窗口坐标系(devicecoordinatesystem:DCS)x,y,z(z:0~1,x,y以窗口左下角为坐标原点)2.模型视点变换场景从世界坐标系到相机坐标系的变换。2.1模型变换在WCS中改变物体的位置、姿态、或缩放2.2视点变换调整相机位置和方向，对场景进行取景3.投影变换场景从相机坐标系到投影坐标系的变换。通过投影矩阵Mprojection来实现：4.视口变换场景从投影坐标系到窗口坐标系的变换。通过投影矩阵Mwindow来实现：ModelTransformOCSMTWCSViewTransformWCSVT（Camera）VCSProjectionTransformVCSPTCCSViewFrustum(视景体)近剪切面远剪切面透视投影，正交投影ViewportTransformCCSVTDCSSomeConcepts

the“camera”you’vecreatedinyour3Dpackageisn’treallyacameraatall.Itjustrepresentsaviewtransformation.Cameraincomputergraphics,wedothisbydefiningwhat’scalleda“viewfrustum”.

Withaviewfrustum,anythinginsidethevolumeofthefrustumisdrawn.Everythingoutsideisexcludedor“clipped”.Projection

Getridofanythingthatisnotintheviewfrustum.ClippingAlloftheoperationsthatwe’vedoneabovearestillin3D(X,Y,Z)coordinates.Weneedtomapthesecoordinatestotheviewpo