DirectX3D中绘制立方体

IDirect3DDevice9* g_Device = NULL;
IDirect3DVertexBuffer9* g_VB = 0; //立方体顶点
IDirect3DIndexBuffer9*  g_IB = 0; //索引数据

struct Vertex {
	Vertex(){}
	Vertex(float x, float y, float z)
	{ _x = x; _y=y; _z=z; }

	float _x, _y, _z;
	static const DWORD FVF;
};
const DWORD Vertex::FVF = D3DFVF_XYZ;

//创建顶点，索引缓存
	g_Device->CreateVertexBuffer(8*sizeof(Vertex),
								 D3DUSAGE_WRITEONLY,
								 Vertex::FVF,
								 D3DPOOL_MANAGED,
								 &g_VB,
								 0);

	g_Device->CreateIndexBuffer(36*sizeof(DWORD),
		D3DUSAGE_WRITEONLY,
		D3DFMT_INDEX16,
		D3DPOOL_MANAGED,
		&g_IB,
		0);

	//向立方体的顶点缓存填充数据
	Vertex* vertices;
	g_VB->Lock(0, 0, (void**)&vertices, 0);
	vertices[0]=Vertex(-1.0f, -1.0f, -1.0f);
	vertices[1]=Vertex(-1.0f, 1.0f, -1.0f);
	vertices[2]=Vertex(1.0f, 1.0f, -1.0f);
	vertices[3]=Vertex(1.0f, -1.0f, -1.0f);
	vertices[4]=Vertex(-1.0f, -1.0f, 1.0f);
	vertices[5]=Vertex(-1.0f, 1.0f, 1.0f);
	vertices[6]=Vertex(1.0f, 1.0f, 1.0f);
	vertices[7]=Vertex(1.0f, -1.0f, 1.0f);
	g_VB->Unlock();

	//定义立方体的三角形
	WORD* indices = 0;
	g_IB->Lock(0,0,(void**)&indices, 0);
	//前面
	indices[0]=0; indices[1]=1; indices[2]=2;
	indices[3]=0; indices[4]=2; indices[5]=3;
	//背面
	indices[6]=4; indices[7]=6; indices[8]=5;
	indices[9]=4; indices[10]=7; indices[11]=6;
	//左面
	indices[12]=4; indices[13]=5; indices[14]=1;
	indices[15]=4; indices[16]=1; indices[17]=0;
	//右面
	indices[18]=3; indices[19]=2; indices[20]=6;
	indices[21]=3; indices[22]=6; indices[23]=7;
	//顶部
	indices[24]=1; indices[25]=5; indices[26]=6;
	indices[27]=1; indices[28]=6; indices[29]=2;
	//底部
	indices[30]=4; indices[31]=0; indices[32]=3;
	indices[33]=4; indices[34]=3; indices[35]=7;

	g_IB->Unlock();

	//照相机位置（视图矩阵）
	D3DXVECTOR3 poistion(0.0f,0.0f,-5.0f);
	D3DXVECTOR3 target(0.0f,0.0f,0.0f);
	D3DXVECTOR3 up(0.0f,1.0f,0.0f);
	D3DXMATRIX V;
	D3DXMatrixLookAtLH(&V, &poistion, &target, &up);
	g_Device->SetTransform(D3DTS_VIEW, &V);

	//投影矩阵
	D3DXMATRIX proj;
	D3DXMatrixPerspectiveFovLH(&proj,
							   D3DX_PI*0.5f, //90-degree
							   (float)WINDOW_WIDTH/(float)WINDOW_HEIGHT,
							   1.0f,
							   1000.0f);
	g_Device->SetTransform(D3DTS_PROJECTION, &proj);

	//渲染状态（填充模式：框架填充）
	g_Device->SetRenderState(D3DRS_FILLMODE, D3DFILL_WIREFRAME);

if (g_Device)
	{
		//旋转立方体
		D3DXMATRIX Rx, Ry;
		//x轴旋转45弧度
		D3DXMatrixRotationX(&Rx, 3.14f/4.0f);
		//每一帧中增加y轴的弧度
		static float y = 0.0f;
		D3DXMatrixRotationY(&Ry, y);
		y += timeDelta;

		//当y轴旋转2周时，重新回到0弧度
		if (y>=6.28f)
			y=0.0f;

		//结合x轴与y轴的旋转矩阵
		D3DXMATRIX p = Rx * Ry;
		g_Device->SetTransform(D3DTS_WORLD, &p);

		//清空目标缓存和深度缓存
		g_Device->Clear(0,0,D3DCLEAR_TARGET | D3DCLEAR_ZBUFFER,
			0xffffffff, 1.0f, 0);

		//开始绘制场景
		g_Device->BeginScene();
		g_Device->SetStreamSource(0, g_VB, 0,sizeof(Vertex)); //设置资源流
		g_Device->SetIndices(g_IB); //设置索引缓存
		g_Device->SetFVF(Vertex::FVF); //设置顶点格式
		//利用索引缓存绘制
		g_Device->DrawIndexedPrimitive(D3DPT_TRIANGLELIST,0,0,8,0,12);
		g_Device->EndScene();//结束绘制场景

		//翻转表面
		g_Device->Present(0,0,0,0);