Direct3D中的绘制—例：绘制正方体

1. 创建顶点缓存和索引缓存
2. 访问缓存内容
3. 设置绘制状态
4. 绘制的准备工作(1)指定数据流输入源。(2)设置顶点格式。(3)设置索引缓存
5. 使用顶点缓存和索引缓存绘制所有的绘制方法要在IDirect3DDevice9::BeginScene()和IDirect3DDevice9::EndScene()之间绘制。
6. const float PI = 3.1415926;
7. IDirect3DDevice9* Device = 0;
8. const int Width = 640;
9. const int Height = 480;
11. IDirect3DVertexBuffer9* VB = 0;
12. IDirect3DIndexBuffer9* IB = 0;
14. //Class and Struct
15. struct Vertex
16. {
17.     Vertex(){}
18.     Vertex(float x, float y, float z)
19.     {
20.         _x = x;
21.         _y = y;
22.         _z = z;
23.     }
24.     float _x, _y, _z;
25.     static const DWORD FVF;
26. };
27. const DWORD Vertex::FVF = D3DFVF_XYZ;
29. //Framework Function
30. bool SetUp()
31. {
32.     //create vertex and index buffer
33.     Device->CreateVertexBuffer(
34.         8*sizeof(Vertex),
35.         D3DUSAGE_WRITEONLY,
36.         Vertex::FVF,
37.         D3DPOOL_MANAGED,
38.         &VB,
39.         0);
40.     Device->CreateIndexBuffer(
41.         36*sizeof(WORD),
42.         D3DUSAGE_WRITEONLY,
43.         D3DFMT_INDEX16,
44.         D3DPOOL_MANAGED,
45.         &IB,
46.         0);
47.     //fill the buffer with the cube data
48.     Vertex* vertices;
49.     VB->Lock(0, 0, (void**)&vertices, 0);
51.     // vertices of a unit cube
52.     vertices[0] = Vertex(-1.0f, -1.0f, -1.0f);
53.     vertices[1] = Vertex(-1.0f, 1.0f, -1.0f);
54.     vertices[2] = Vertex( 1.0f, 1.0f, -1.0f);
55.     vertices[3] = Vertex( 1.0f, -1.0f, -1.0f);
56.     vertices[4] = Vertex(-1.0f, -1.0f, 1.0f);
57.     vertices[5] = Vertex(-1.0f, 1.0f, 1.0f);
58.     vertices[6] = Vertex( 1.0f, 1.0f, 1.0f);
59.     vertices[7] = Vertex( 1.0f, -1.0f, 1.0f);
61.     VB->Unlock();
63.     // define the triangles of the cube:
64.     WORD* indices = 0;
65.     IB->Lock(0, 0, (void**)&indices, 0);
67.     // front side
68.     indices[0] = 0; indices[1] = 1; indices[2] = 2;
69.     indices[3] = 0; indices[4] = 2; indices[5] = 3;
71.     // back side
72.     indices[6] = 4; indices[7] = 6; indices[8] = 5;
73.     indices[9] = 4; indices[10] = 7; indices[11] = 6;
75.     // left side
76.     indices[12] = 4; indices[13] = 5; indices[14] = 1;
77.     indices[15] = 4; indices[16] = 1; indices[17] = 0;
79.     // right side
80.     indices[18] = 3; indices[19] = 2; indices[20] = 6;
81.     indices[21] = 3; indices[22] = 6; indices[23] = 7;
83.     // top
84.     indices[24] = 1; indices[25] = 5; indices[26] = 6;
85.     indices[27] = 1; indices[28] = 6; indices[29] = 2;
87.     // bottom
88.     indices[30] = 4; indices[31] = 0; indices[32] = 3;
89.     indices[33] = 4; indices[34] = 3; indices[35] = 7;
91.     IB->Unlock();
93.     D3DXVECTOR3 position(0.0f, 0.0f, -5.0f);
94.     D3DXVECTOR3 target(0.0f, 0.0f, 0.0f);
95.     D3DXVECTOR3 up(0.0f, 1.0f, 0.0f);
96.     D3DXMATRIX V;
97.     D3DXMatrixLookAtLH(&V, &position, &target, &up);
99.     Device->SetTransform(D3DTS_VIEW, &V);
100.     //set projection matrix
101.     
102.     D3DXMATRIX proj;
103.     D3DXMatrixPerspectiveFovLH(
104.         &proj,
105.         D3DX_PI*0.5f,
106.         (float)Width/(float)Height,
107.         1.0f,
108.         1000.0f);
109.     Device->SetTransform(D3DTS_PROJECTION, &proj);
110.     //Swtich to wirefarm mode
112.     Device->SetRenderState(D3DRS_FILLMODE, D3DFILL_WIREFRAME);
113.     return true;
114. }
115. void CleanUp()
116. {
117.     d3d::Release<IDirect3DVertexBuffer9*>(VB);
118.     d3d::Release<IDirect3DIndexBuffer9*>(IB);
119. }
120. bool Display(float timeDetla)
121. {
122.     if(Device)
123.     {
124.         D3DXMATRIX Rx,Ry;
125.         D3DXMatrixRotationX(&Rx, 3.14/4.0f);
126.         static float y = 0.0f;
127.         D3DXMatrixRotationY(&Ry, y);
128.         y+=timeDetla;
130.         if(y>=6.28)
131.         {
132.             y = 0.0f;
133.         }
134.         D3DXMATRIX p = Rx * Ry;
135.         //把旋转后的矩阵转换到世界坐标系中
136.         Device->SetTransform(D3DTS_WORLD, &p);
137.         //绘制scence
138.         Device->Clear(0, 0, D3DCLEAR_TARGET|D3DCLEAR_ZBUFFER, 0xffffffff, 1.0f, 0);
139.         Device->BeginScene();
141.         Device->SetStreamSource(0, VB, 0, sizeof(Vertex));            //指定数据流输入源
142.         Device->SetIndices(IB);                                        //设置索引缓存
143.         Device->SetFVF(Vertex::FVF);                                //指定定点格式
144.         
146.         //绘制正方体
147.         Device->DrawIndexedPrimitive(D3DPT_TRIANGLELIST, 0, 0, 8, 0, 12);
148.         Device->EndScene();
149.         Device->Present(0,0,0,0);
150.     }
151.     return true;
152. }