Direct3D学习笔记

1. 初始化

a. 获得IDirect3D9 接口的指针

b. 检查设备（显卡）的能力， D3DCAPS9

c. 初始化D3DPRESENT_PARAMETERS结构，这个结构是为下一步服务的

d. 基于D3DPRESENT_PARAMETERS结构，创建IDirect3DDevice9

相关代码：

  
 IDirect3DDevice9* Device = 0; 
    HRESULT hr = 0;

	// Step 1: Create the IDirect3D9 object.

	IDirect3D9* d3d9 = 0;
    d3d9 = Direct3DCreate9(D3D_SDK_VERSION);

    if( !d3d9 )
	{
		::MessageBox(0, _T("Direct3DCreate9() - FAILED"), 0, 0);
		return false;
	}

	// Step 2: Check for hardware vp.

	D3DCAPS9 caps;
	d3d9->GetDeviceCaps(D3DADAPTER_DEFAULT, deviceType, &caps);

	int vp = 0;
	if( caps.DevCaps & D3DDEVCAPS_HWTRANSFORMANDLIGHT )
		vp = D3DCREATE_HARDWARE_VERTEXPROCESSING;
	else
		vp = D3DCREATE_SOFTWARE_VERTEXPROCESSING;

	// Step 3: Fill out the D3DPRESENT_PARAMETERS structure.
 
	D3DPRESENT_PARAMETERS d3dpp;
	d3dpp.BackBufferWidth            = 640;
	d3dpp.BackBufferHeight           = 480;
	d3dpp.BackBufferFormat           = D3DFMT_A8R8G8B8;
	d3dpp.BackBufferCount            = 1;
	d3dpp.MultiSampleType            = D3DMULTISAMPLE_NONE;
	d3dpp.MultiSampleQuality         = 0;
	d3dpp.SwapEffect                 = D3DSWAPEFFECT_DISCARD; 
	d3dpp.hDeviceWindow              = hwnd;
	d3dpp.Windowed                   = windowed;
	d3dpp.EnableAutoDepthStencil     = true; 
	d3dpp.AutoDepthStencilFormat     = D3DFMT_D24S8;
	d3dpp.Flags                      = 0;
	d3dpp.FullScreen_RefreshRateInHz = D3DPRESENT_RATE_DEFAULT;
	d3dpp.PresentationInterval       = D3DPRESENT_INTERVAL_IMMEDIATE;

	// Step 4: Create the device.

	hr = d3d9->CreateDevice(
		D3DADAPTER_DEFAULT, // primary adapter
		D3DDEVTYPE_HAL,         // device type
		hwnd,               // window associated with device
		vp,                 // vertex processing
	    &d3dpp,             // present parameters
	    device);            // return created device
         d3dpp.Release();

上面代码的执行结果就是生成一个窗口， 得到了一个IDirect3DDevice9。

注：这里省略了Windows 32窗体的生成过程

2. 画面的现实

在上面我们得到了一个IDirect3DDevice9, 我们就可以用此device进行画图等操作。

bool Display()
{
	if( Device ) // Only use Device methods if we have a valid device.
	{
		// Instruct the device to set each pixel on the back buffer black -
		// D3DCLEAR_TARGET: 0x00000000 (black) - and to set each pixel on
		// the depth buffer to a value of 1.0 - D3DCLEAR_ZBUFFER: 1.0f.
		Device->Clear(0, 0, D3DCLEAR_TARGET | D3DCLEAR_ZBUFFER, 0x00000000, 1.0f, 0);

		// Swap the back and front buffers.
		Device->Present(0, 0, 0, 0);
	}
	return true;
}

这样一个可以画图的device就形成了