Visual C++游戏编程基础之位图绘制

一、位图绘制步骤

1.加载位图，这里要用到函数LoadImage( )，其函数原型如下：

HANDLE LoadImage（
    HINSTANCE hinst， //实例句柄
    LPCTSTR lpszName，//指向图像的名称
    UINT uType，      //指定图像类型，这里是装载位图
    int cxDesired，   //加载宽度
    int cyDesired     //加载高度
    UINT fuLoad；     //加载方式，这里是来自文件
}；

2.建立与窗口兼容的内存DC

函数原型：HDC CreateCompatibleDC(HDC hdc)；

       功能：创建一个与指定设备兼容的内存设备上下文环境（DC）；

函数原型：BOOL DeleteDC(HDC hdc)；

       功能：内存DC使用结束后，使用DeleteDC( )释放内存

3.选择位图对象

函数原型：HGDIOBJ SelectObject(HDC hdc, HGDIOBJ hgdiobj)；

      功能：选择一对象到指定的设备上下文环境中，该新对象替换先前的相同类型的对象

4.贴图

二、代码实现

#include "stdafx.h"

HINSTANCE hInst;
HBITMAP hbmp;//declare a bitmap object
HDC		mdc; //declare a memory DC

ATOM				MyRegisterClass(HINSTANCE hInstance);
BOOL				InitInstance(HINSTANCE, int);
LRESULT CALLBACK	WndProc(HWND, UINT, WPARAM, LPARAM);
void				MyPaint(HDC hdc);


int APIENTRY WinMain(HINSTANCE hInstance,
                     HINSTANCE hPrevInstance,
                     LPSTR     lpCmdLine,
                     int       nCmdShow)
{
	MSG msg;
	
	MyRegisterClass(hInstance);
	
	
	if (!InitInstance (hInstance, nCmdShow)) 
	{
		return FALSE;
	}
	
	
	while (GetMessage(&msg, NULL, 0, 0)) 
	{
		TranslateMessage(&msg);
		DispatchMessage(&msg);
	}
	
	return msg.wParam;
}


ATOM MyRegisterClass(HINSTANCE hInstance)
{
	WNDCLASSEX wcex;
	
	wcex.cbSize =sizeof(WNDCLASSEX); 
	wcex.style			= CS_HREDRAW | CS_VREDRAW;
	wcex.lpfnWndProc	= (WNDPROC)WndProc;
	wcex.cbClsExtra		= 0;
	wcex.cbWndExtra		= 0;
	wcex.hInstance		= hInstance;
	wcex.hIcon			= NULL;
	wcex.hCursor		= NULL;
	wcex.hCursor		= LoadCursor(NULL, IDC_ARROW);
	wcex.hbrBackground	= (HBRUSH)(COLOR_WINDOW+1);
	wcex.lpszMenuName	= NULL;
	wcex.lpszClassName	= "canvas";
	wcex.hIconSm		= NULL;
	
	return RegisterClassEx(&wcex);
}

BOOL InitInstance(HINSTANCE hInstance, int nCmdShow)
{
	HWND hWnd;
	HDC hdc;
	
	hInst = hInstance;
	
	hWnd = CreateWindow("canvas", "绘图窗口" , WS_OVERLAPPEDWINDOW,
		CW_USEDEFAULT, 0, CW_USEDEFAULT, 0, NULL, NULL, hInstance, NULL);
	
	if (!hWnd)
	{
		return FALSE;
	}
	
	MoveWindow(hWnd,10,10,600,450,true);
	ShowWindow(hWnd, nCmdShow);
	UpdateWindow(hWnd);
	
	hdc = GetDC(hWnd);
	mdc = CreateCompatibleDC(hdc);//create a DC-compatible environment
	
	hbmp = (HBITMAP)LoadImage(NULL,"bg.bmp",IMAGE_BITMAP,600,400,LR_LOADFROMFILE); 
	SelectObject(mdc,hbmp);
	
	MyPaint(hdc);
	ReleaseDC(hWnd,hdc);
	
	return TRUE;
}


void MyPaint(HDC hdc)
{
	BitBlt(hdc,0,0,600,400,mdc,0,0,SRCCOPY);//把内存DC上的位图贴到设备DC上	
}


LRESULT CALLBACK WndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
{
	PAINTSTRUCT ps;
	HDC hdc;
	
	switch (message)
	{
	case WM_PAINT:						
		hdc = BeginPaint(hWnd, &ps);
		MyPaint(hdc);
		EndPaint(hWnd, &ps);
		break;
	case WM_DESTROY:					
		DeleteDC(mdc);
		DeleteObject(hbmp);
		PostQuitMessage(0);
		break;
	default:						
		return DefWindowProc(hWnd, message, wParam, lParam);
	}
	return 0;
}

四、效果