ddutil.cpp

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//-----------------------------------------------------------------------------
// File: ddutil.cpp
//
// Desc: DirectDraw framewark classes. Feel free to use this class as a 
//       starting point for adding extra functionality.
//
//
// Copyright (c) 1995-1999 Microsoft Corporation. All rights reserved.
//-----------------------------------------------------------------------------
#define STRICT
#include <tchar.h>
#include <windows.h>
#include <windowsx.h>
#include <ddraw.h>
#include "ddutil.h"


//-----------------------------------------------------------------------------
// Name: CDisplay()
// Desc:
//-----------------------------------------------------------------------------
CDisplay::CDisplay()
{
    m_pDD                = NULL;	//设置初值
    m_pddsFrontBuffer    = NULL;
    m_pddsBackBuffer     = NULL;
}


//-----------------------------------------------------------------------------
// Name: ~CDisplay()
// Desc:
//-----------------------------------------------------------------------------
CDisplay::~CDisplay()
{
    DestroyObjects();
}


//-----------------------------------------------------------------------------
// Name: DestroyObjects()
// Desc: 释放已建立的对象
//-----------------------------------------------------------------------------
HRESULT CDisplay::DestroyObjects()
{
    SAFE_RELEASE( m_pddsBackBuffer );
    SAFE_RELEASE( m_pddsFrontBuffer );

    if( m_pDD )		
        m_pDD->SetCooperativeLevel( m_hWnd, DDSCL_NORMAL );//取消与窗口的关联

    SAFE_RELEASE( m_pDD );

    return S_OK;
}


//-----------------------------------------------------------------------------
// Name: CreateFullScreenDisplay()
// Desc: 创建DirectX对象
// 参数：窗口句柄，屏幕宽度，高度，深度
//-----------------------------------------------------------------------------
HRESULT CDisplay::Create( HWND hWnd, DWORD dwWidth, DWORD dwHeight, DWORD dwBPP )
{
    HRESULT hr;

    // 释放已建立的对象
    DestroyObjects();

    // 创建DirectX对象(NULL,DirectX对象指针,DirectX对象类型,NULL)
    if( FAILED( hr = DirectDrawCreateEx( NULL, (VOID**)&m_pDD,
                                         IID_IDirectDraw7, NULL ) ) )
        return E_FAIL;

    // 设置关联的窗口（窗口句柄，方式
    hr = m_pDD->SetCooperativeLevel( hWnd, DDSCL_EXCLUSIVE|DDSCL_FULLSCREEN );
    if( FAILED(hr) )
        return E_FAIL;

    // 设置显示的模式（设置颜色时应与深度位数相对应）
    if( FAILED( m_pDD->SetDisplayMode( dwWidth, dwHeight, dwBPP, 0, 0 ) ) )
        return E_FAIL;

    // 创建前平面结构
    DDSURFACEDESC2 ddsd;
    ZeroMemory( &ddsd, sizeof( ddsd ) );
    ddsd.dwSize            = sizeof( ddsd );	//设置结构长度
    ddsd.dwFlags           = DDSD_CAPS | DDSD_BACKBUFFERCOUNT;	//有效选项
    ddsd.ddsCaps.dwCaps    = DDSCAPS_PRIMARYSURFACE | DDSCAPS_FLIP |	//方式
                             DDSCAPS_COMPLEX | DDSCAPS_3DDEVICE;
    ddsd.dwBackBufferCount = 1;	//后平面个数
	
	//创建前平面（平面结构指针，前平面指针，NULL)
    if( FAILED( hr = m_pDD->CreateSurface( &ddsd, &m_pddsFrontBuffer,	
                                           NULL ) ) )
        return E_FAIL;

    // 设置平面信息结构
    DDSCAPS2 ddscaps;
    ZeroMemory( &ddscaps, sizeof( ddscaps ) );
    ddscaps.dwCaps = DDSCAPS_BACKBUFFER;	//设置为后平面

	//创建后平面对象
    if( FAILED( hr = m_pddsFrontBuffer->GetAttachedSurface( &ddscaps,
                                                            &m_pddsBackBuffer ) ) )
        return E_FAIL;

    m_pddsBackBuffer->AddRef();	//向系统申请加1

    m_hWnd      = hWnd;	//保存场口句柄
    return S_OK;
}
    

//-----------------------------------------------------------------------------
// Name: CDisplay::CreateSurfaceFromBitmap()
// Desc: Create a DirectDrawSurface from a bitmap resource or bitmap file.
//       Use MAKEINTRESOURCE() to pass a constant into strBMP.
// Desc: 通过位图创建一个位图平面
// 参数：平面类指针，位图字符串，希望使用的宽度，希望使用的高度
//-----------------------------------------------------------------------------
HRESULT CDisplay::CreateSurfaceFromBitmap( CSurface** ppSurface,
                                           TCHAR* strBMP,                                            
                                           DWORD dwDesiredWidth, 
                                           DWORD dwDesiredHeight )
{
    HRESULT        hr;
    HBITMAP        hBMP = NULL;
    BITMAP         bmp;
    DDSURFACEDESC2 ddsd;

    if( m_pDD == NULL || strBMP == NULL || ppSurface == NULL )	//判断创建条件 
        return E_INVALIDARG;

    *ppSurface = NULL;	//清除前面的内容

    //  从资源中调用位图
    hBMP = (HBITMAP) LoadImage( GetModuleHandle(NULL), strBMP, 
                                IMAGE_BITMAP, dwDesiredWidth, dwDesiredHeight, 
                                LR_CREATEDIBSECTION );
    if( hBMP == NULL )
    {
		//从文件中调用位图
        hBMP = (HBITMAP) LoadImage( NULL, strBMP, 
                                    IMAGE_BITMAP, dwDesiredWidth, dwDesiredHeight, 
                                    LR_LOADFROMFILE | LR_CREATEDIBSECTION );
        if( hBMP == NULL )
            return E_FAIL;
    }

    //得到位图句柄
    GetObject( hBMP, sizeof(bmp), &bmp );

    // 从位图创建平面结构
    ZeroMemory( &ddsd, sizeof(ddsd) );
    ddsd.dwSize         = sizeof(ddsd);	//设置结构尺寸
    ddsd.dwFlags        = DDSD_CAPS | DDSD_HEIGHT | DDSD_WIDTH;	//有效信息
    ddsd.ddsCaps.dwCaps = DDSCAPS_OFFSCREENPLAIN;
    ddsd.dwWidth        = bmp.bmWidth;	//平面的宽度和高度（不能更改）
    ddsd.dwHeight       = bmp.bmHeight;

    (*ppSurface) = new CSurface();	//创建新平面
    if( FAILED( hr = (*ppSurface)->Create( m_pDD, &ddsd ) ) )	//通过结构创建平面
    {
        delete (*ppSurface);
        return hr;
    }

    // 将位图画入平面
    if( FAILED( hr = (*ppSurface)->DrawBitmap( hBMP ) ) )
    {
        DeleteObject( hBMP );
        return hr;
    }

    DeleteObject( hBMP );	//删除位图指针

    return S_OK;
}


//-----------------------------------------------------------------------------
// Name: CDisplay::CreateSurfaceFromText()
// Desc: Creates a DirectDrawSurface from a text string using hFont or the default 
//       GDI font if hFont is NULL.
// Desc: 通过文字创建一个文字平面
// 参数：平面类指针，字体，文字内容，背景颜色，前景颜色
//-----------------------------------------------------------------------------
HRESULT CDisplay::CreateSurfaceFromText( CSurface** ppSurface,
                                         HFONT hFont, TCHAR* strText, 
                                         COLORREF crBackground, COLORREF crForeground )
{
    HDC                  hDC  = NULL;
    LPDIRECTDRAWSURFACE7 pDDS = NULL;
    HRESULT              hr;
    DDSURFACEDESC2       ddsd;
    SIZE                 sizeText;

    if( m_pDD == NULL || strText == NULL || ppSurface == NULL )//判断条件
        return E_INVALIDARG;

    *ppSurface = NULL;//清除前面的内容

    hDC = GetDC( NULL ); //创建设备DC

    if( hFont )
        SelectObject( hDC, hFont );	//如果没有设置字体，则使用默认字体

    GetTextExtentPoint32( hDC, strText, _tcslen(strText), &sizeText );	//得到显示文字的尺寸
    ReleaseDC( NULL, hDC );

    // Create a DirectDrawSurface for this bitmap
    ZeroMemory( &ddsd, sizeof(ddsd) );
    ddsd.dwSize         = sizeof(ddsd);	//设置结构尺寸
    ddsd.dwFlags        = DDSD_CAPS | DDSD_HEIGHT | DDSD_WIDTH;//有效信息
    ddsd.ddsCaps.dwCaps = DDSCAPS_OFFSCREENPLAIN;
    ddsd.dwWidth        = sizeText.cx;//平面的宽度和高度（不能更改）
    ddsd.dwHeight       = sizeText.cy;

    (*ppSurface) = new CSurface();
    if( FAILED( hr = (*ppSurface)->Create( m_pDD, &ddsd ) ) )	//通过结构创建平面
    {
        delete (*ppSurface);
        return hr;
    }

    // 将文字写入平面
    if( FAILED( hr = (*ppSurface)->DrawText( hFont, strText, crBackground, crForeground ) ) )
        return hr;

    return S_OK;
}


//-----------------------------------------------------------------------------
// Name: 交换前后平面
// 参数: 
//-----------------------------------------------------------------------------
HRESULT CDisplay::Present()
{
    HRESULT hr;

    if( NULL == m_pddsFrontBuffer && NULL == m_pddsBackBuffer )	//判断条件
        return E_POINTER;

    while( 1 )
    {
        hr = m_pddsFrontBuffer->Flip( NULL, 0 );	//将前后平面交换，来显示刚刚画好的屏幕

        if( hr == DDERR_SURFACELOST )	//平面丢失了
        {	
            m_pddsFrontBuffer->Restore();	//恢复平面
            m_pddsBackBuffer->Restore();
        }

        if( hr != DDERR_WASSTILLDRAWING )
            return hr;
    }
}


//-----------------------------------------------------------------------------
// Name: 将平面位图画到后平面上
// 参数: 后平面上的x坐标,后平面上的y坐标,平面对象，位图（文字）平面上的一个矩形区域，方式
//-----------------------------------------------------------------------------