Visual C++游戏编程基础之透明动画

一、原理

1.利用前面学过的透明处理，这一次相当于是对每一帧图片进行透明处理，如第一次循环对第一帧进行透明处理，接着显示；第二次对第二帧透明处理，接着显示，直到最后一帧，然后再从第一帧开始，就这样无限循环

二、代码如下

#include "stdafx.h"

HINSTANCE hInst;
HBITMAP dra,bg;//bg为背景图，dra为恐龙连续跑动，前景图及屏蔽图
HDC		hdc,mdc,bufdc;//hdc为窗口DC句柄；mdc储存要贴到窗口上的内容，并在此内存DC上进行透明处理；bufdc选取位图时用的DC
HWND	hWnd;
DWORD	tPre,tNow;//记录上一次绘图的时间；记录此次准备绘图的时间
int		num,x,y;//通过改变位图坐标，来改变恐龙的运动位置，相当于利用坐标更换来刷新图片;num用来记录图号

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( msg.message!=WM_QUIT )
    {
        if( PeekMessage( &msg, NULL, 0,0 ,PM_REMOVE) )
        {
            TranslateMessage( &msg );
            DispatchMessage( &msg );
        }
		else
		{
			tNow = GetTickCount();
			if(tNow-tPre >= 100)//每隔0.1s贴一次
				MyPaint(hdc);
		}
    }

	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)
{
	char filename[20] = "";
	HBITMAP bmp;
	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,10,10,640,520,true);
	ShowWindow(hWnd, nCmdShow);
	UpdateWindow(hWnd);

	hdc = GetDC(hWnd);
	mdc = CreateCompatibleDC(hdc);
	bufdc = CreateCompatibleDC(hdc);
	bmp = CreateCompatibleBitmap(hdc,640,480);//建立空的位图对象bmp

	SelectObject(mdc,bmp);//将bmp存储到mdc中

	dra = (HBITMAP)LoadImage(NULL,"dra.bmp",IMAGE_BITMAP,760,198,LR_LOADFROMFILE);
	bg = (HBITMAP)LoadImage(NULL,"bg.bmp",IMAGE_BITMAP,640,480,LR_LOADFROMFILE);

	num = 0;    //图号
	x = 640;	//贴图起始X坐标，这时候恐龙在窗口的外面
	y = 360;    //贴图起始Y坐标

	MyPaint(hdc);

	return TRUE;
}

void MyPaint(HDC hdc)
{
	if(num == 8)
		num = 0;

	SelectObject(bufdc,bg);
	BitBlt(mdc,0,0,640,480,bufdc,0,0,SRCCOPY);//先把背景图贴到mdc

	SelectObject(bufdc,dra);
	BitBlt(mdc,x,y,95,99,bufdc,num*95,99,SRCAND);
	BitBlt(mdc,x,y,95,99,bufdc,num*95,0,SRCPAINT);//对恐龙图进行透明处理后贴到mdc

	BitBlt(hdc,0,0,640,480,mdc,0,0,SRCCOPY);//把mdc中的位图贴到hdc中，即每paint一次，就贴一次，bg每次都重复贴，恐龙位置发生变化

	tPre = GetTickCount();     //记录绘图后的时间，到下一轮准备绘图之间的时间，这个用来调整游戏运行速度，即每一帧的刷新频率
	num++;

	x-=20;					   
	if(x<=-95)//95是指恐龙图的宽，也就是它跑过窗口的最左侧至完全消失，其左上角坐标为(-95,y)
		x = 640;
}

LRESULT CALLBACK WndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
{
	switch (message)
	{
		case WM_DESTROY:					
			DeleteDC(mdc);
			DeleteDC(bufdc);
			DeleteObject(dra);
			DeleteObject(bg);
			ReleaseDC(hWnd,hdc);
			PostQuitMessage(0);
			break;
		default:							
			return DefWindowProc(hWnd, message, wParam, lParam);
   }
   return 0;
}

三、效果