Visual C++游戏编程基础之多背景循环动画 - 好文

一、基本思路

1.现在有三张背景图：天空和草地、山峦、房屋；

2.天空在最远处，其次是草地和山峦(因为山峦在草地上)，最后是房屋；

3.背景的循环速度是天空最慢、然后是山峦、最后是草地和房屋；

4.恐龙让它原地跑动，以num记录图号，每次到末尾号，再从第0号开始；

二、背景循环贴图

1.以天空为例，设x0表示背景图从左向右滚动右边需要切割的宽度，初值为0；

2.设背景图宽度640，裁剪的右边区域的左上角坐标为：(640-x0,0)，把该区域贴到mdc以(0,0)为起点的坐标区域上;

3.然后把天空图剩下的部分贴到mdc中以(x0,0)为起点的坐标上;

4.假设每次x0增加5，每次贴图就实现了背景图的移动，直到x=640时，再重新设为0；

5.需要注意，山峦和房屋除了实现循环外，还要进行透明处理；

三、代码如下
#include "stdafx.h" HINSTANCE hInst; HBITMAP dra,bg[3]; HDC hdc,mdc,bufdc;
HWND hWnd; DWORD tPre,tNow; int
x0=0,x1=0,x2=0,num=0;//x0、x1、x2三张背景图由左向右移动时所要切割的宽度;num表示图号 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) 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) { 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);
SelectObject(mdc,bmp); bg[0] =
(HBITMAP)LoadImage(NULL,"bg0.bmp",IMAGE_BITMAP,640,480,LR_LOADFROMFILE); bg[1]
= (HBITMAP)LoadImage(NULL,"bg1.bmp",IMAGE_BITMAP,640,600,LR_LOADFROMFILE);
bg[2] =
(HBITMAP)LoadImage(NULL,"bg2.bmp",IMAGE_BITMAP,640,600,LR_LOADFROMFILE); dra =
(HBITMAP)LoadImage(NULL,"dra.bmp",IMAGE_BITMAP,760,198,LR_LOADFROMFILE);
MyPaint(hdc); return TRUE; } void MyPaint(HDC hdc) { //贴上天空背景图
SelectObject(bufdc,bg[0]); BitBlt(mdc,0,0,x0,300,bufdc,640-x0,0,SRCCOPY);
BitBlt(mdc,x0,0,640-x0,300,bufdc,0,0,SRCCOPY); //贴上草地图
BitBlt(mdc,0,300,x2,180,bufdc,640-x2,300,SRCCOPY);
BitBlt(mdc,x2,300,640-x2,180,bufdc,0,300,SRCCOPY); //贴上山峦并透明
SelectObject(bufdc,bg[1]); BitBlt(mdc,0,0,x1,300,bufdc,640-x1,300,SRCAND);
BitBlt(mdc,x1,0,640-x1,300,bufdc,0,300,SRCAND);
BitBlt(mdc,0,0,x1,300,bufdc,640-x1,0,SRCPAINT);
BitBlt(mdc,x1,0,640-x1,300,bufdc,0,0,SRCPAINT); //贴上房屋并透明
SelectObject(bufdc,bg[2]); BitBlt(mdc,0,250,x2,300,bufdc,640-x2,300,SRCAND);
BitBlt(mdc,x2,250,640-x2,300,bufdc,0,300,SRCAND);
BitBlt(mdc,0,250,x2,300,bufdc,640-x2,0,SRCPAINT);
BitBlt(mdc,x2,250,640-x2,300,bufdc,0,0,SRCPAINT); SelectObject(bufdc,dra);
BitBlt(mdc,250,350,95,99,bufdc,num*95,99,SRCAND);
BitBlt(mdc,250,350,95,99,bufdc,num*95,0,SRCPAINT);
BitBlt(hdc,0,0,640,480,mdc,0,0,SRCCOPY); tPre = GetTickCount(); //控制各个背景图的循环速度
x0 += 5; if(x0==640) x0 = 0; x1 += 8; if(x1==640) x1 = 0; x2 += 16; if(x2==640)
x2 = 0; num++; if(num == 8) num = 0; } LRESULT CALLBACK WndProc(HWND hWnd, UINT
message, WPARAM wParam, LPARAM lParam) { switch (message) { case WM_DESTROY:
DeleteDC(mdc); DeleteDC(bufdc); DeleteObject(bg[0]); DeleteObject(bg[1]);
DeleteObject(bg[2]); DeleteObject(dra); ReleaseDC(hWnd,hdc);
PostQuitMessage(0); break; default: return DefWindowProc(hWnd, message, wParam,
lParam); } return 0; }
四、效果

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