3.实现人机交互

    玩家利用键盘的四个方向键操纵小动物在迷宫中移动，为了捕获玩家对键盘的操作，需要在对话框中重载PreTranslateMessage函数，函数只对上、下、左、右四个按键进行处理，根据前进方向是否有围墙来移动小动物，移动小动物的函数为MoveIcon()。实现的代码如下：

BOOL CMyDlg::PreTranslateMessage(MSG* pMsg)

{

    // TODO: Add your specialized code here and/or call the base class

    if (pMsg->message == WM_KEYDOWN)        /*如果玩家按下按键*/

    {

        switch (pMsg->wParam)

        {      

        case VK_UP:     /*按“上”键，如上方无围墙，则调用MoveIcon移动小动物*/

            if ( !maze.HWall[int(maze.current_x)][int(maze.current_y)] )

                MoveIcon(VK_UP);

            break;

        case VK_DOWN:       /*向下*/

            if ( !maze.HWall[int(maze.current_x)][int(maze.current_y+1)] )

                MoveIcon(VK_DOWN);

            break;

        case VK_LEFT:       /*向左*/

            if ( !maze.VWall[int(maze.current_x)][int(maze.current_y)] )

                MoveIcon(VK_LEFT);

            break;

        case VK_RIGHT:      /*向右*/

            if ( !maze.VWall[int(maze.current_x+1)][int(maze.current_y)] )

                MoveIcon(VK_RIGHT);

            break;

        default:

            break;

        }

    }