《几何模型显》PPT课件

第3章坐标系与基本图元,Direct3D坐标系,在空间几何中，绝大多数情况下使用笛卡尔坐标系为参照系来表示图形，表三维图形时需要使用三维笛卡尔坐标系。三维笛卡尔坐标系根据z坐标轴相对x,y坐标轴方向的不同，可分为左手坐标系和右手坐标系，它们的区别方法是：将右手食指、中指、无名指和小拇指顺着x轴正向到y轴正向旋转的方向，如果大拇指的方向和z轴正向相同，就是右手坐标系，反之就左手坐标系。,左手坐标系,右手坐标系,Direct程序中常用坐标系,(150,50),(50,250),(250,250),本程序执行结果,FVF灵活顶点格式,FVF(FlexibleVertexFormat)用来描述在顶点缓冲区中的顶点存储格式中包含了哪些属性。根据图形显示的需要，顶缓冲区中的格式可以包含顶点坐标、颜色、法线方向、纹理坐标等属性。,FVF标记数据的用途,FVF灵活顶点格式说明符,structCUSTOMVERTEXfloatx,y,z,rhw,color;#defineD3DFVF_CUSTOMVERTEX(D3DFVF_XYZ|D3DFVF_DIFFUSE)CUSTOMVERTEXvertices=150.0f,50.0f,0.5f,1.0f,0 xffff0000,/x,y,z,rhw,color250.0f,250.0f,0.5f,1.0f,0 xff00ff00,50.0f,250.0f,0.5f,1.0f,0 xff00ffff,;,三角形的FVF定义如下：,文件首部,#includeLPDIRECT3D9g_pD3D=NULL;LPDIRECT3DDEVICE9g_pd3dDevice=NULL;LPDIRECT3DVERTEXBUFFER9g_pVB=NULL;/顶点缓冲区structCUSTOMVERTEXFLOATx,y,z,rhw;/顶点坐标DWORDcolor;/顶点颜色;#defineD3DFVF_CUSTOMVERTEX(D3DFVF_XYZRHW|D3DFVF_DIFFUSE),颜色值的顺序,0 xAARRGGBBALPHA值：0 x000 xffR、G、B均为：0 x000 xff,HRESULTInitVB()CUSTOMVERTEXvertices=150.0f,50.0f,0.5f,1.0f,0 xffff0000,/x,y,z,rhw,color250.0f,250.0f,0.5f,1.0f,0 xff00ff00,50.0f,250.0f,0.5f,1.0f,0 xff00ffff,;if(FAILED(g_pd3dDevice-CreateVertexBuffer(3*sizeof(CUSTOMVERTEX),0,D3DFVF_CUSTOMVERTEX,D3DPOOL_DEFAULT,创建顶点缓冲区,在使用顶缓冲区绘图前，首先要创建顶点缓冲区，其原型如下：HRESULTIDirect3DDevice9:CreateVertexBuffer(UINTLength,/顶点缓冲区的大小DWORDUsage,/顶点缓冲区的属性DWORDFVF,/灵活顶点格式D3DPOOLPool,/在内存中的位置IDirect3DVertexBuffer9*ppVertexBuffer,/缓冲/区指针Handle*pSharedHandle/保留参数),CreateVertexBuffer()参数说明,Usage：一般设为0或取下列值,D3DPOOL取值,向顶点缓冲区写入数据,如果不向顶点缓冲区填入有用数据的话，顶点缓冲是没有用的，所以必须向顶点缓冲填充数据，在写入数据前需要调用Lock函数加锁缓冲区。,Lock()函数原型,HRESULTIDirect3DVertexBuffer:Lock(UINTOffsetToLock,/加锁地址UINTSizeToLock,/加锁内存大小VOID*ppbDATA,/内存指针地址DWORDflags/加锁属性);,Lock参数说明,缓冲区加锁属性可取下列值或0,顶点缓冲区图形显示,Render()函数,VOIDRender()g_pd3dDevice-Clear(0,NULL,D3DCLEAR_TARGET,D3DCOLOR_XRGB(0,0,255),1.0f,0);if(SUCCEEDED(g_pd3dDevice-BeginScene()g_pd3dDevice-SetStreamSource(0,g_pVB,0,sizeof(CUSTOMVERTEX);g_pd3dDevice-SetFVF(D3DFVF_CUSTOMVERTEX);g_pd3dDevice-DrawPrimitive(D3DPT_TRIANGLELIST,0,1);g_pd3dDevice-EndScene();g_pd3dDevice-Present(NULL,NULL,NULL,NULL);,SetStreamSource()函数原型,HRESULTIDirect3DDevice9:SetStreamSource(UINTStreamNumber,/渲染数据流序号IDirect3DVertexBuffer9*pStreamData,/进行绑定链接的顶点缓冲区指针UINTOffsetInBytes,/进行绑定链接的渲染数据流的起始位置UINTStride/渲染数据流中一个顶点所占的内存大小。);,SetFVF()函数原型,HRESULTIDirect3DDevice9:SetFVF(DWORDFVF/渲染数据流中的灵活顶点格式);,D3D图元绘制函数,HRESHULTIDirect3DDevice9:DrawPrimive(D3DPRIMIVETYPEPrimitiveType,/图元类型UINTStartVertex,/起始点位置UINTPrimitiveCount/图元数目);,6种基本图元,g_d3dDevice-DrawPrimitive(D3DPT_POINTLIST,0,6),(0.0,5.0,0.0),(0.0,5.0,0.0),(0.0,5.0,0.0),(0.0,5.0,0.0),(0.0,5.0,0.0),(0.0,5.0,0.0),g_d3dDevice-DrawPrimitive(D3DPT_LINELIST,0,3),(0.0,5.0,0.0),(0.0,5.0,0.0),(0.0,5.0,0.0),(0.0,5.0,0.0),(0.0,5.0,0.0),(0.0,5.0,0.0),g_d3dDevice-DrawPrimitive(D3DPT_LINESTRIP,0,5),(0.0,5.0,0.0),(0.0,5.0,0.0),(0.0,5.0,0.0),(0.0,5.0,0.0),(0.0,5.0,0.0),(0.0,5.0,0.0),g_d3dDevice-DrawPrimitive(D3DPT_TRIANGLELIST,0,2),(0.0,5.0,0.0),(0.0,5.0,0.0),(0.0,5.0,0.0),(0.0,5.0,0.0),(0.0,5.0,0.0),(0.0,5.0,0.0),g_d3dDevice-DrawPrimitive(D3DPT_TRIANGLESTRIP,0,4),(0.0,5.0,0.0),(0.0,5.0,0.0),(0.0,5.0,0.0),(0.0,5.0,0.0),(0.0,5.0,0.0),(0.0,5.0,0.0),D3DPTTRIANGLEFAN示例,基本图元显示实例,使用索引缓冲区绘制图形,顶点结构及类型的定义,StructCUSTOMVERTEXFLOATx,y,z,rhw;DWORDcolor;#defineD3DFVF_CUTOMVERTEX(D3DFVF_XYZRHW|D3DFVF_DIFFUSE),顶点数组及索引数组的定义,CUSTOMVERTEXg_Vertices9;g_Vertices0.x=300;g_Vertices0.y=250;g_Vertices0.z=0.5f;g_Vertices0.rhw=1.0f;g_Vertices0.color=0 xffff0000;for(inti=0;iCreateIndexBuffer(sizeof(g_Index),0,D3DFMT_INDEX16,D3DPOOL_DEFAULT,CreateIndexBuffer函数原型,CreateIndexBuffer(UINTLength,DWORDUsage,D3DFORMATformat,D3DPOOLPool,IDirect3DIndexBuffer9*ppIndexBuffer,Handle*pHandle);,使用索引绘图的代码片段,if(SUCCEEDED(g_pD3DDevice-BeginScene()g_pD3DDevice-SetStreamSource(0,g_pVB,0,sizeof(CUSTOMVERTEX);g_pD3DDevice-SetFVF(D3DFVF_CUSTOMVERTEX);g_pD3DDevice-SetIndices(g_pIB);g_pD3DDevice-DrawIndexedPrimitive(D3DPT_TRIANGLELIST,0,0,4,0,2);g_pD3DDevice-EndScene();g_pD3DDevice-Present(NULL,NULL,NULL,NULL);,D