游戏编程中的人工智能(2－3)

来源：互联网发布：apache ftpclient 530 编辑：程序博客网时间：2024/06/16 12:12

2.2 文本

如何在画布上签名？下面就要解决这个问题。

2.2.1 TextOut

朝屏幕输出文本最简单的方法就是使用TextOut函数。下面看一下它的原型：

BOOL TextOut(

HDC hdc, //DC句柄

int nXStart, //开始写入位置的X坐标

int nYStart, //开始写入位置的Y坐标

LPCTSTR lpString, //指向字符串的指针

int cbString //字符串的字符数

);

首先向TextOut传入DC句柄，还有需要文本显示的坐标，一个字符串指针，最后是一个表示文本长度的整数。文本默认的颜色是黑色，默认的背景色是WHITE_BRUSH。

2.2.2 DrawText

DrawText比TextOut稍微复杂一点。它的原型如下：

int DrawText(

HDC hdc, //DC句柄

LPCTSTR lpString, //指向待写入字符串的指针

int nCount, //字符串的长度(字符个数)

LPRECT lpRect, //指向格式化大小结构的指针

UINT uFormat //文本书写标识

);

这个函数在lpRect指定的文本框里显示文本。文本根据uFormat标志设置。

uFormat：设置文本格式化

表2.2DrawText格式化标志

样式

描述

DT_BOTTOM

文本在文本框内底部对齐。若要使用本标志，必须同时使用DT_SINGLELINE标志

DT_CENTER

这个标志使文本在文本框内水平居中

DT_LEFT

文本左对齐

DT_RIGHT

文本右对齐

DT_SINGLELINE

在单行里显示所有文字。有回车键文字也不换行

DT_TOP

文本顶部对齐

DT_WORDBREAK

这个标志的效果类似于字的换行

2.2.3 加入颜色和透明度

在Windows中可以自己定义背景色和前景色，还可以设置文本的透明度。为了设置文本颜色，需要利用SetTextColor函数：

COLORREF SetTextColor(

HDC hdc, //DC句柄

COLORREF crColor //文本颜色

);

设置背景色用SetBkColor函数：

COLORREF SetBkColor(

HDC hdc, //DC句柄

COLORREF crColor //背景颜色

);

设置完成以后，前景和背景色会一直有效，直到再次修改为止。两个函数都返回当前的颜色值，用户可以记录最初的设置，以便在必要时恢复。

为了将文本颜色设为红色而背景设为黑色，可以执行下面这些语句。

除了能够设置前景和背景色以外，还可以设置透明度。这把显示到屏幕上的文本的背景部分变成了透明(例如，如果文本背后是一个图案，则看起来就像是把文字直接打印到图案上一样)。

可以用SetBkMode函数设置背景的透明度：

int SetBkMode(

HDC hdc, //DC句柄

int iBkMode //用以指明背景模式标志

);

只有两个标志可用：OPAQUE(不透明)和TRANSPARENT(透明)。因此，要使用透明背景绘制文本的时候，在具体绘制之前，应设置合适的背景模式。

GDI_Text的源代码示范了所有这些函数的使用。

默然：这里有两个文件：main.cpp和defines.h

首先是main.cpp

嗯，我不逐句翻译了，只把与前面不同的地方翻译一下。

//-----------------------------------------------------------------------

// Name: GDI_Text示例工程

// Author: Mat Buckland 2002

// Desc: 代码演示了文本输出

//------------------------------------------------------------------------

#include <windows.h>

#include <time.h>

#include "defines.h"

//--------------------------------- Globals ------------------------------

//------------------------------------------------------------------------

char* g_szApplicationName = "The Groovy GDI - Text Output";

char* g_szWindowClassName = "MyWindowClass";

//---------------------------- WindowProc ---------------------------------

// This is the callback function which handles all the windows messages

//-------------------------------------------------------------------------

LRESULT CALLBACK WindowProc (HWND hwnd,

UINT msg,

WPARAM wParam,

LPARAM lParam)

{

//these hold the dimensions of the client window area

static int cxClient, cyClient;

switch (msg)

{

//A WM_CREATE msg is sent when your application window is first

//created

case WM_CREATE:

{

//to get get the size of the client window first we need to create

//a RECT and then ask Windows to fill in our RECT structure with

//the client window size. Then we assign to cxClient and cyClient

//accordingly

RECT rect;

GetClientRect(hwnd, &rect);

cxClient = rect.right;

cyClient = rect.bottom;

}

break;

case WM_KEYUP:

{

switch(wParam)

{

case VK_ESCAPE:

{

PostQuitMessage(0);

}

break;

}

case WM_PAINT:

{

PAINTSTRUCT ps;

BeginPaint (hwnd, &ps);

//Make the bottom part of window a pattern so you can see what

//the transparency flag does

HBRUSH PatternBrush = CreateHatchBrush(HS_BDIAGONAL, RGB(0,0,255));

HBRUSH OldBrush = (HBRUSH)SelectObject(ps.hdc, PatternBrush);

Rectangle(ps.hdc,0, cyClient/2, cxClient, cyClient);

//替换回旧画刷

SelectObject(ps.hdc, OldBrush);

//首先，演示用TextOut输出演示文本

char* text = "1. I ain't got time to bleed.";

TextOut(ps.hdc, 5, 5, text, strlen(text));

//现在是DrawText.首先我们创建一个文本框

RECT TextBox;

TextBox.top = 30;

TextBox.left = 100;

TextBox.bottom = 200;

TextBox.right = cxClient-100;

//文本赋值

text = "2. You take the blue pill and the story ends.You wake in your bed and believe whatever you want to believe.You take the red pill and you stay in Wonderland and I show you how deep the rabbit-hole goes.";

//现在，画文本

DrawText(ps.hdc, text, strlen(text), &TextBox, DT_WORDBREAK);

//现在改变颜色，先设置文本为红色

SetTextColor(ps.hdc, RGB(255, 0, 0));

//设置背景为黑色

SetBkColor(ps.hdc, RGB(0, 0, 0));

TextBox.top = 200;

TextBox.left = 5;

TextBox.bottom = 300;

TextBox.right = cxClient-200;

text = "3. The greatest trick the devil ever pulled was convincing the world he didn't exist.";

DrawText(ps.hdc, text, strlen(text), &TextBox, DT_WORDBREAK);

//现在，设置背景透明

SetBkMode(ps.hdc, TRANSPARENT);

TextBox.top = 300;

TextBox.left = 100;

TextBox.bottom = cyClient;

TextBox.right = cxClient-50;

text = "4. ...I抦 42 years old. In less than a year I抣l be dead";

DrawText(ps.hdc, text, strlen(text), &TextBox, DT_WORDBREAK);

EndPaint (hwnd, &ps);

}

break;

//has the user resized the client area?

case WM_SIZE:

{

//if so we need to update our variables so that any drawing

//we do using cxClient and cyClient is scaled accordingly

cxClient = LOWORD(lParam);

cyClient = HIWORD(lParam);

}

break;

case WM_DESTROY:

{

// kill the application, this sends a WM_QUIT message

PostQuitMessage (0);

}

break;

}//end switch

//this is where all the messages not specifically handled by our

//winproc are sent to be processed

return DefWindowProc (hwnd, msg, wParam, lParam);

}

//-------------------------------- WinMain -------------------------------

// The entry point of the windows program

//------------------------------------------------------------------------

int WINAPI WinMain (HINSTANCE hInstance,

HINSTANCE hPrevInstance,

LPSTR szCmdLine,

int iCmdShow)

{

//handle to our window

HWND hWnd;

//our window class structure

WNDCLASSEX winclass;

// first fill in the window class stucture

winclass.cbSize = sizeof(WNDCLASSEX);

winclass.style = CS_HREDRAW | CS_VREDRAW;

winclass.lpfnWndProc = WindowProc;

winclass.cbClsExtra = 0;

winclass.cbWndExtra = 0;

winclass.hInstance = hInstance;

winclass.hIcon = LoadIcon(NULL, IDI_APPLICATION);

winclass.hCursor = LoadCursor(NULL, IDC_ARROW);

winclass.hbrBackground = (HBRUSH)GetStockObject (WHITE_BRUSH);

winclass.lpszMenuName = NULL;

winclass.lpszClassName = g_szWindowClassName;

winclass.hIconSm = LoadIcon(NULL, IDI_APPLICATION);

//register the window class

if (!RegisterClassEx(&winclass))

{

MessageBox(NULL, "Registration Failed!", "Error", 0);

//exit the application

return 0;

}

//create the window and assign its ID to hwnd

hWnd = CreateWindowEx (NULL, // extended style

g_szWindowClassName, // window class name

g_szApplicationName, // window caption

WS_OVERLAPPEDWINDOW, // window style

0, // initial x position

0, // initial y position

WINDOW_WIDTH, // initial x size

WINDOW_HEIGHT, // initial y size

NULL, // parent window handle

NULL, // window menu handle

hInstance, // program instance handle

NULL); // creation parameters

//make sure the window creation has gone OK

if(!hWnd)

{

MessageBox(NULL, "CreateWindowEx Failed!", "Error!", 0);

}

//make the window visible

ShowWindow (hWnd, iCmdShow);

UpdateWindow (hWnd);

//this will hold any windows messages

MSG msg;

//entry point of our message handler

while (GetMessage (&msg, NULL, 0, 0))

{

TranslateMessage (&msg);

DispatchMessage (&msg);

}

UnregisterClass( g_szWindowClassName, winclass.hInstance );

return msg.wParam;

}

然后，是defines.h

#ifndef DEFINES_H

#define DEFINES_H

#define WINDOW_WIDTH 400

#define WINDOW_HEIGHT 400

#endif

2.2.4 实时消息抽取循环

在GDI_Polygon例子里，每次需要显示一个新的多边形，就得按一次空格键，这可能显得有点繁琐。但怎样才能在屏幕上连续不断地显示新的多边形来催眠用户呢？仅用GetMessage是办不到的。如果消息队列中没有消息，GetMessage就会等待，直到新的消息出现在队列中。需要这样一种消息循环，只有在需要处理消息时才去处理消息，其余的时间都让游戏代码去自动产生激动的场面。为了做到这一点，可以使用PeekMessage函数。其原型如下：

BOOL PeekMessage(

LPMSG lpMsg, //message结构指针

HWND hWnd, //窗口句柄

UINT wMsgFilterMin, //指定被检查的消息范围里的第一个message

UINT wMsgFilterMax, //指定被检查的消息范围里的最后的message

UINT wRemoveMsg //移走标志

);

最后一个参数wRemoveMsg，它的值可以是PM_NOREMOVE(消息处理后仍保留在队列中)，或PM_REMOVE(消息处理后移走)，通常选择后者。如果队列中有消息，PeekMessage将返回true，否则返回false。

要创建实时的消息抽取循环，就需要更复杂一些，如果只把GetMessage替换作PeekMessage，那么，当队列中没有消息时，PeekMessage返回零，应用程序会因此而终止。下面尝试用另一种形式来修改绘制多边形的例子。

while(PeekMessage(&msg,NULL,0,0,PM_))

{

TranslateMessage(&msg);

DispatchMessage(&msg);

}

这样只会见到应用程序窗口闪电般地打开，接着就立即关闭。而实际中需要的是一个更为强健的设计，过程如下：

//进入message抽取循环

bool bDone=false;

MSG msg;

while(!bDone){

while(PeekMessage(&msg,NULL,0,0,PM_REMOVE)){

if(msg.message==WM_QUIT){

//如果是quit消息，就退出循环

bDone=true;

}else{

TranslateMessage(&msg);

DispatchMessage(&msg);

}

//下面是调用WM_PAINT绘制场景

InvalidateRect(hWnd,NULL,TRUE);

UpdateWindow(hWnd);

}

从GDI_Polygon2例子里的消息循环的运行情况中，可以发现WindowProc中的WM_PAINT部分现在包含产生新多边形的代码。这里利用了小巧的Sleep函数让程序每帧有几毫秒的延迟，这样就能实际看清每个多边形。调用Sleep时，参数表示程序应当暂停的毫秒数，暂停过后，程序接着就自动继续运行。

默然：下面公布GDI_Ploygon2的源代码，由于只有main.cpp与GDI_Ploygon不同，所以这里只列出了main.cpp的源代码，并只翻译了改变部分的注释。

//-----------------------------------------------------------------------

// Name: GDI_Polygon2 example project

// Author: Mat Buckland 2002

// Desc: Code demonstrating the creation and use of a realtime message

// pump

//------------------------------------------------------------------------

#include <windows.h>

#include <time.h>

#include "defines.h"

#include "utils.h"

//--------------------------------- Globals ------------------------------

//------------------------------------------------------------------------

char* g_szApplicationName = "The Groovy GDI - Dazzle";

char* g_szWindowClassName = "MyWindowClass";

//---------------------------- WindowProc ---------------------------------

// This is the callback function which handles all the windows messages

//-------------------------------------------------------------------------

LRESULT CALLBACK WindowProc (HWND hwnd,

UINT msg,

WPARAM wParam,

LPARAM lParam)

{

//create some pens to use for drawing

static HPEN BluePen = CreatePen(PS_SOLID, 1, RGB(0, 0, 255));

static HPEN OldPen = NULL;

//create a solid brush

static HBRUSH RedBrush = CreateSolidBrush(RGB(255, 0, 0));

static HBRUSH OldBrush = NULL;

//these hold the dimensions of the client window area

static int cxClient, cyClient;

//this will hold the vertices of the polygons we create

static POINT verts[NUM_VERTS];

static int iNumVerts = NUM_VERTS;

switch (msg)

{

//A WM_CREATE msg is sent when your application window is first

//created

case WM_CREATE:

{

//to get get the size of the client window first we need to create

//a RECT and then ask Windows to fill in our RECT structure with

//the client window size. Then we assign to cxClient and cyClient

//accordingly

RECT rect;

GetClientRect(hwnd, &rect);

cxClient = rect.right;

cyClient = rect.bottom;

//seed random number generator

srand((unsigned) time(NULL));

//now lets create some random vertices

for (int v=0; v<iNumVerts; ++v)

{

verts[v].x = RandInt(0, cxClient);

verts[v].y = RandInt(0, cyClient);

}

break;

case WM_KEYUP:

{

switch(wParam)

{

case VK_SPACE:

{

//create some new points for our polygon

//now lets create some random vertices

for (int v=0; v<iNumVerts; ++v)

{

verts[v].x = RandInt(0, cxClient);

verts[v].y = RandInt(0, cyClient);

}

//refresh the display so we can see our

//new polygon

InvalidateRect(hwnd, NULL, TRUE);

UpdateWindow(hwnd);

}

break;

case VK_ESCAPE:

{

PostQuitMessage(0);

}

break;

}

case WM_PAINT:

{

//create some random vertices for the polygon

for (int v=0; v<iNumVerts; ++v)

{

verts[v].x = RandInt(0, cxClient);

verts[v].y = RandInt(0, cyClient);

}

PAINTSTRUCT ps;

BeginPaint (hwnd, &ps);

//first select a pen to draw with and store a copy

//of the pen we are swapping it with

OldPen = (HPEN)SelectObject(ps.hdc, BluePen);

//do the same for our brush

OldBrush = (HBRUSH)SelectObject(ps.hdc, RedBrush);

//draw the polygon

Polygon(ps.hdc, verts, iNumVerts);

//replace the original pen

SelectObject(ps.hdc, OldPen);

//and brush

SelectObject(ps.hdc, OldBrush);

EndPaint (hwnd, &ps);

//使用这个简单的Sleep，我们就可以控制绘制多边形的频率，以便让我们看清多边形

Sleep(100);

}

break;

//has the user resized the client area?

case WM_SIZE:

{

//if so we need to update our variables so that any drawing

//we do using cxClient and cyClient is scaled accordingly

cxClient = LOWORD(lParam);

cyClient = HIWORD(lParam);

//create a new polygon

for (int v=0; v<iNumVerts; ++v)

{

verts[v].x = RandInt(0, cxClient);

verts[v].y = RandInt(0, cyClient);

}

break;

case WM_DESTROY:

{

//delete the pens

DeleteObject(BluePen);

DeleteObject(OldPen);

//and the brushes

DeleteObject(RedBrush);

DeleteObject(OldBrush);

// kill the application, this sends a WM_QUIT message

PostQuitMessage (0);

}

break;

}//end switch

//this is where all the messages not specifically handled by our

//winproc are sent to be processed

return DefWindowProc (hwnd, msg, wParam, lParam);

}

//-------------------------------- WinMain -------------------------------

// The entry point of the windows program

//------------------------------------------------------------------------

int WINAPI WinMain (HINSTANCE hInstance,

HINSTANCE hPrevInstance,

LPSTR szCmdLine,

int iCmdShow)

{

//handle to our window

HWND hWnd;

//our window class structure

WNDCLASSEX winclass;

// first fill in the window class stucture

winclass.cbSize = sizeof(WNDCLASSEX);

winclass.style = CS_HREDRAW | CS_VREDRAW;

winclass.lpfnWndProc = WindowProc;

winclass.cbClsExtra = 0;

winclass.cbWndExtra = 0;

winclass.hInstance = hInstance;

winclass.hIcon = LoadIcon(NULL, IDI_APPLICATION);

winclass.hCursor = LoadCursor(NULL, IDC_ARROW);

winclass.hbrBackground = (HBRUSH)GetStockObject (WHITE_BRUSH);

winclass.lpszMenuName = NULL;

winclass.lpszClassName = g_szWindowClassName;

winclass.hIconSm = LoadIcon(NULL, IDI_APPLICATION);

//register the window class

if (!RegisterClassEx(&winclass))

{

MessageBox(NULL, "Registration Failed!", "Error", 0);

//exit the application

return 0;

}

//create the window and assign its ID to hwnd

hWnd = CreateWindowEx (NULL, // extended style

g_szWindowClassName, // window class name

g_szApplicationName, // window caption

WS_OVERLAPPEDWINDOW, // window style

0, // initial x position

0, // initial y position

WINDOW_WIDTH, // initial x size

WINDOW_HEIGHT, // initial y size

NULL, // parent window handle

NULL, // window menu handle

hInstance, // program instance handle

NULL); // creation parameters

//make sure the window creation has gone OK

if(!hWnd)

{

MessageBox(NULL, "CreateWindowEx Failed!", "Error!", 0);

}

//make the window visible

ShowWindow (hWnd, iCmdShow);

UpdateWindow (hWnd);

//进行消息循环

bool bDone = false;

MSG msg;

while(!bDone)

{

while( PeekMessage( &msg, NULL, 0, 0, PM_REMOVE ) )

{

if( msg.message == WM_QUIT )

{

// 如果是程序退出消息则停止循环

bDone = true;

}

else

{

TranslateMessage( &msg );

DispatchMessage( &msg );

}

//这里会调用WM_PAINT，完成对我们的窗口的重绘

InvalidateRect(hWnd, NULL, TRUE);

UpdateWindow(hWnd);

//*** 你的游戏主循环应该就放在这里 ***//

}//end while

UnregisterClass( g_szWindowClassName, winclass.hInstance );

return msg.wParam;

}

您好：
    当您在阅读和使用我所提供的各种内容的时候，我非常感谢，您的阅读已是对我最大的支持。
    我更希望您能给予我更多的支持。
    1.希望您帮助我宣传我的博客，让更多的人知道它，从中获益(别忘记了提醒他们帮我点点广告，嘿嘿)。
    2.希望您能多提出宝贵意见，包括我所提供的内容中的错误，建设性的意见，更希望获得哪些方面的帮助，您的经验之谈等等。
    3.更希望能得到您经济上的支持。

    我博客上面的内容均属于个人的经验，所有的内容均为开源内容，允许您用于任何非商业用途，并不以付费为前提，如果您觉得在阅读和使用我所提供的各种内容的过程中，您得到了帮助，并能在经济上给予我支持，我将感激不尽。

您可以通过点击我网站上的广告表示对我的支持。

    您可以通过银行转帐付款给我：
    招商银行一卡通：
    卡号：6225888712586894
    姓名：牟勇

    您也可以通过汇款的方式：
    通讯地址：云南省昆明市女子(28)中学人民中路如意巷1号
    收信人：陈谦转牟勇收
    邮编：650021

    无论您给予我怎么样的支持，我都衷心的再次感谢。
    欢迎光临我的博客，欢迎宣传我的博客
    http://blog.csdn.net/mouyong
    http://blog.sina.com.cn/mouyong
    EMail:mouyong@yeah.net
    QQ:11167603
    MSN:mouyong1973@hotmail.com