游戏脚本管理 (一)

前言：

在自己制作了单机泡泡堂的游戏之后,感觉应该加入游戏脚本的支持,通过一段时间学习,我将学的一些步骤和经验包括代码写了下来.
　

一、实现以指令为基础的游戏脚本语言

　　现在说的是理论方法，你马上可以实现一种以指令为基础的语言。首先设计一组简单的指令，用于显示文本,并加入简单的循环。最终用MessageBox对话框显示出来。

设计语言第一个步骤，建立自己的指令，为了更直观我建立一个指令表,列表如下：

二、编写一个脚本

首先确认你认为所需要的功能，目前它就是上表列的４条指令。它最好为一个标准的文本文件。

PrintString "这是一种以指令为基础的语言"
PrintString "也是一个简单的脚本代码"
Newline
PrintString "但它相当的简单"
Newline
PrintStringLoop "将被输出４次" 4
Newline
PrintString "等下将执行等待按键操作"
WaitForKeyPress
　

三、编写TScript类

这段代码相当简单，主要体现于分解字符串的操作，根据不同的指令来执行不同的代码。

unit uScripting;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms;

const

 //四个指令的常量定义
  COMMAND_PRINTSTRING = 'PrintString';
  COMMAND_NEWLINE   = 'Newline';
  COMMAND_PRINTSTRINGLOOP = 'PrintStringLoop';
  COMMAND_WAITFORKEYPRESS = 'WaitForKeyPress';

type
  TScript = class
  private
    FCommandList: TStrings;  //保存脚本
    procedure GetCommand(Index: integer; var strCommand: string);  //获取一个命令
    procedure GetStrParam(Index: integer; var strParam: string);  //获取一个字符串参数
    procedure GetIntParam(Index: integer; var intParam: integer);  //获取一个整形参数
  public
    constructor Create;
    destructor Destroy; override;
    procedure LoadScript(AFile: string);  //装入脚本
    procedure UnLoadScript;  //清空脚本
    procedure RunScript();  //运行脚本
  end;

implementation

{ TScript }

constructor TScript.Create;
begin
  FCommandList := TStringList.Create;
end;

destructor TScript.Destroy;
begin
  FCommandList.Clear;
  FCommandList.Free;
  inherited Destroy;
end;

procedure TScript.GetCommand(Index: integer; var strCommand: string);
begin
  if Pos(#32, Trim(FCommandList.Strings[Index])) <> 0 then
    strCommand := Trim(Copy(Trim(FCommandList.Strings[Index]), 1, Pos(#32,
      Trim(FCommandList.Strings[Index]))))
  else
    strCommand := Trim(FCommandList.Strings[Index]);
end;

procedure TScript.GetIntParam(Index: integer;
  var intParam: integer);
var
  cCurrChar         : string;
  g_iCurrScriptLineChar: Integer;
begin

  g_iCurrScriptLineChar := Pos('"', FCommandList.Strings[Index]) + 1;
  g_iCurrScriptLineChar := Pos('"', Copy(FCommandList.Strings[Index],
    g_iCurrScriptLineChar + 1, length(FCommandList.Strings[Index]))) +
    g_iCurrScriptLineChar + 1;
  intParam := 0;

  while (g_iCurrScriptLineChar <= Length(FCommandList.Strings[Index])) do
  begin
    cCurrChar := copy(FCommandList.Strings[Index], g_iCurrScriptLineChar, 1);
    if (cCurrChar = '#') or (cCurrChar = #13) or (cCurrChar = #10) then
      break;
    if (cCurrChar[1] in ['0'..'9']) then
      intParam := StrToInt(IntToStr(intParam) + cCurrChar);
    inc(g_iCurrScriptLineChar, 1);
  end;

end;

procedure TScript.GetStrParam(Index: integer;
  var strParam: string);
var
  cCurrChar         : string;
  g_iCurrScriptLineChar: Integer;
begin

  g_iCurrScriptLineChar := Pos('"', FCommandList.Strings[Index]) + 1;
  strParam := ';

  while (g_iCurrScriptLineChar < Length(FCommandList.Strings[Index])) do
  begin
    cCurrChar := copy(FCommandList.Strings[Index], g_iCurrScriptLineChar, 1);
    if (cCurrChar = '"') or (cCurrChar = #13) or (cCurrChar = #10) then
      break;
    strParam := strParam + cCurrChar;
    inc(g_iCurrScriptLineChar, 1);
  end;

end;

procedure TScript.LoadScript(AFile: string);
begin
  if FileExists(AFile) then
    FCommandList.LoadFromFile(AFile)
  else
    raise Exception.Create('无效的脚本文件');
end;

procedure TScript.RunScript;
var
  strCommand        : string;
  strParam          : string;
  intParam          : integer;
  i                 : Integer;
  iCurr             : integer;
  sResult           : string;
begin
  if FCommandList.Count < 0 then
    Exit;
  sResult := ';

  for i := 0 to FCommandList.Count - 1 do
  begin
    GetCommand(i, strCommand);
    if Uppercase(strCommand) = Uppercase(COMMAND_PRINTSTRING) then  //检查指令是否匹配
    begin
      GetStrParam(i, strParam);  //获取字符串参数
      sResult := sResult + strParam + #13#10;  //保存结果
    end
    else if UpperCase(strCommand) = UpperCase(COMMAND_PRINTSTRINGLOOP) then
    begin
      GetStrParam(i, strParam);
      GetIntParam(i, intParam);  //获取整形参数

      for iCurr := 0 to intParam - 1 do
      begin
        sResult := sResult + strParam + #13#10;  //循环输出次数
      end;
    end
    else if UpperCase(strCommand) = UpperCase(COMMAND_NEWLINE) then
    begin
      sResult := sResult + #13#10;
    end
    else if UpperCase(strCommand) = UpperCase(COMMAND_WAITFORKEYPRESS) then
    begin
      Application.Title := '等待按键';
      while true do
      begin
        Application.ProcessMessages;
        if GetInputState() then
          break;
      end;
      Application.Title := '按键完成'; 
    end
    else
    begin
      sResult := sResult + '无效指令！' + #13#10;
    end;

  end;

  Application.MessageBox(PAnsiChar(sResult), '运行结果', 0);

end;

procedure TScript.UnLoadScript;
begin
  FCommandList.Clear;
end;

end.

这里是测试代码。

procedure TGameMain.Button1Click(Sender: TObject); //请在form中放入一个button 后粘贴代码到单击事件中
var
FScript : TScript;
begin
FScript := TScript.Create;
FScript.LoadScript('E:\projects\GameEngine\Scripts\Test.src');  //修改为你保存脚本的路径
(Sender as TButton).Enabled := FALSE;
FScript.RunScript;  //等待按键时只需要单击一下form即可继续运行。
(Sender as TButton).Enabled := TRUE;
FScript.Free;
end;

这里是关于上面代码的图解说明：

 

PrintString

NewLine

WaitForKeyPress

RunScript()

Text Console

 阅读完上述的内容后，下一回将讲解如何解释向这样的脚本指令：

DrawBitmap "gfx/copyright.bmp"
PlaySound "sound/ambient.wav"
Pause 3000
PlaySound "sound/wipe.wav"
FoldCloseEffectY
DrawBitmap "gfx/ynh_presents.bmp"
PlaySound "sound/ambient.wav"
Pause 3000
PlaySound "sound/wipe.wav"
FoldCloseEffectX
DrawBitmap "gfx/title.bmp"
PlaySound "sound/title.wav"
WaitForKeyPress
PlaySound "sound/wipe.wav"
FoldCloseEffectY
Exit

再见！2004年11月