Lesson 14: SDK文档：Tutorial02 Rendering a Triangle分析

头文件：

#include <windows.h>
#include <d3d11.h>
#include <d3dx11.h>
#include <d3dcompiler.h>
#include <xnamath.h>
#include "resource.h"

结构体声明：

// Structures
struct SimpleVertex
{
    D3DXVECTOR3 Pos;
};

全局变量声明：

// Global Variables
HINSTANCE               g_hInst = NULL; //实例句柄
HWND                    g_hWnd = NULL;  //窗口句柄
D3D_DRIVER_TYPE         g_driverType = D3D_DRIVER_TYPE_NULL;    //驱动类型
D3D_FEATURE_LEVEL       g_featureLevel = D3D_FEATURE_LEVEL_11_0;    //特征等级
ID3D11Device*           g_pd3dDevice = NULL;    //设备接口指针
ID3D11DeviceContext*    g_pImmediateContext = NULL; //设备上下文接口指针
IDXGISwapChain*         g_pSwapChain = NULL;    //交换链接口指针
ID3D11RenderTargetView* g_pRenderTargetView = NULL; //渲染目标视图接口指针
ID3D11VertexShader*     g_pVertexShader = NULL; //顶点着色器接口指针
ID3D11PixelShader*      g_pPixelShader = NULL;  //像素着色器接口指针
ID3D11InputLayout*      g_pVertexLayout = NULL; //输入布局接口指针
ID3D11Buffer*           g_pVertexBuffer = NULL; //缓冲区接口指针

注：
D3D10_DRIVER_TYPE的MSDN资料：
https://msdn.microsoft.com/pt-br/library/windows/apps/bb205042.aspx

函数声明：

// Forward declarations
HRESULT InitWindow( HINSTANCE hInstance, int nCmdShow );    //初始化窗口函数
HRESULT InitDevice();   //初始化设备函数
void CleanupDevice();   //清除设备函数
LRESULT CALLBACK    WndProc( HWND, UINT, WPARAM, LPARAM );  //窗口过程函数
void Render();  //渲染函数

程序的入口点函数：

// Entry point to the program. Initializes everything and goes into a message processing loop. Idle time is used to render the scene.
int WINAPI wWinMain( HINSTANCE hInstance, HINSTANCE hPrevInstance, LPWSTR lpCmdLine, int nCmdShow )
{
    UNREFERENCED_PARAMETER( hPrevInstance );
    UNREFERENCED_PARAMETER( lpCmdLine );

    //初始化窗口
    if( FAILED( InitWindow( hInstance, nCmdShow ) ) )
        return 0;

    //初始化设备
    if( FAILED( InitDevice() ) )
    {
        //初始化失败，清除设备
        CleanupDevice();
        return 0;
    }

    //消息主循环
    // Main message loop
    //消息结构体MSG
    MSG msg = {
  0};
    //当没有接收到退出程序消息时，继续循环
    while( WM_QUIT != msg.message )
    {
        //获取消息
        //如果有消息，则对消息进行转译、分发
        if( PeekMessage( &msg, NULL, 0, 0, PM_REMOVE ) )
        {
            TranslateMessage( &msg );
            DispatchMessage( &msg );
        }
        //如果没有消息，则进行渲染
        else
        {
            Render();
        }
    }

    //清除设备
    CleanupDevice();

    return ( int )msg.wParam;
}

初始化窗口函数：

// 该函数用于注册窗口类以及创建窗口
// Register class and create win