《几何模型显》PPT课件.ppt

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1、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(Flexible Vertex Format)用来描述在

2、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,struct CUSTOMVERTEXfloat x,y,z,rhw,color;#define D3DFVF_CUSTOMVERTEX(D3DFVF_XYZ|D3DFVF_DIFFUSE)CUSTOMVERTEX vertices=150.0f,50.0f,0.5f,1.0f,0 xffff0000,/x,y,z,rhw,color 250.0f,250.0f,0.5f,1.0f,0 xff00ff00,50.0f

3、,250.0f,0.5f,1.0f,0 xff00ffff,;,三角形的FVF定义如下：,文件首部,#include LPDIRECT3D9 g_pD3D=NULL;LPDIRECT3DDEVICE9 g_pd3dDevice=NULL;LPDIRECT3DVERTEXBUFFER9 g_pVB=NULL;/顶点缓冲区struct CUSTOMVERTEX FLOAT x,y,z,rhw;/顶点坐标 DWORD color;/顶点颜色;#define D3DFVF_CUSTOMVERTEX(D3DFVF_XYZRHW|D3DFVF_DIFFUSE),颜色值的顺序,0 xAARRGGBBALPH

4、A值：0 x000 xffR、G、B均为：0 x00 0 xff,HRESULT InitVB()CUSTOMVERTEX vertices=150.0f,50.0f,0.5f,1.0f,0 xffff0000,/x,y,z,rhw,color 250.0f,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

5、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：HRESULT IDirect3DDevice9:CreateVertexBuffer(UINT Length,/顶点缓冲区的大小 DWORD Usage,/顶点缓冲区的属性 DWORD FVF,/灵活顶点格式 D3DPOOL Pool,/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

6、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,HRESULT IDirect3DVertexBuffer:Lock(UINT OffsetToLock,/加锁地址 UINT SizeToLock,/加锁内存大小 VOID*ppbDATA,/内存指针地址 DWORD flags/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,VOID Render()g_pd3dDevice-Clear(0,NULL,D3DCLEAR_TARGET,D3D

7、COLOR_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

8、()函数原型,HRESULTIDirect3DDevice9:SetStreamSource(UINT StreamNumber,/渲染数据流序号 IDirect3DVertexBuffer9*pStreamData,/进行绑定链接的顶点缓冲区指针 UINT OffsetInBytes,/进行绑定链接的渲染数据流的起始位置 UINT Stride/渲染数据流中一个顶点所占的内存大小。);,SetFVF()函数原型,HRESULT IDirect3DDevice9:SetFVF(DWORD FVF/渲染数据流中的灵活顶点格式);,D3D图元绘制函数,HRESHULT IDirect3DDevic

9、e9:DrawPrimive(D3DPRIMIVETYPE PrimitiveType,/图元类型 UINT StartVertex,/起始点位置 UINT PrimitiveCount/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),(

10、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

11、,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,Struct CUSTOMVERTEX FLOAT x,y,z,rhw;DWORD color;#define D3DFVF_CUTOMVERTEX(D3DFV

12、F_XYZRHW|D3DFVF_DIFFUSE),顶点数组及索引数组的定义,CUSTOMVERTEX g_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(int i=0;i8;i+)g_Verticesi+1.x=(float)(200*sin(i*3.14159/4.0)+300;g_Verticesi+1.y=-(float)(200*cos(i*3.14159/4.0)+250;g_Vertices

13、i+1.z=0.5f;g_Verticesi+1.rhw=1.0f;g_Verticesi+1.color=0 xff00ff00;/顶点索引数组WORD g_Indices=0,1,2,0,2,3,0,3,4,0,4,5,0,5,6,0,6,7,0,7,8,0,8,1;,建立索引缓冲区的代码片段,LPDIRECT3DINDEXBUFFER9 g_pIB=NULL;if(FAILED(g_pD3DDevice-CreateIndexBuffer(sizeof(g_Index),0,D3DFMT_INDEX16,D3DPOOL_DEFAULT,CreateIndexBuffer函数原型,Crea

14、teIndexBuffer(UINT Length,DWORD Usage,D3DFORMAT format,D3DPOOL Pool,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_pI

15、B);g_pD3DDevice-DrawIndexedPrimitive(D3DPT_TRIANGLELIST,0,0,4,0,2);g_pD3DDevice-EndScene();g_pD3DDevice-Present(NULL,NULL,NULL,NULL);,DrawIndexedPrimitive函数原型,DrawIndexedPrimitive(D3DPRIMITIVETYPE Type,INT BaseVertexIndex,UINT MinIndex,UINT NumVertices,UINT StartIndex,UINT PrimitiveCount);,作业：利用索引缓冲区绘制下列矩形,0(50,50),3(250,50),2(50,250),1(250,250),