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[size="3"][font="Calibri"][heading]XNA 4.0 Scripting[/heading][/font]

[subheading]Objectives of this journal:[/subheading][/font][font="Calibri"][size="3"]
[/font][font="Calibri"][size="3"][font="Calibri"][size="3"][font="Calibri"][size="3"][font="Calibri"][size="3"][font="Calibri"][size="3"][font="Calibri"][size="3"][font="Calibri"][size="3"][font="Calibri"][size="3"][/font][/font][/font][/font][/font][font="Calibri"][size="3"]-Receive feedback on the whole thing and especially alternatives to my ObjectTranslator, because it is extremely sloppy and I do not like it. It feels like a complete hack.[/font][/font][/font][font="Calibri"][size="3"]

[/font][/font][size="3"][font="Calibri"][subheading]Notes:[/subheading]
[/font][font="Calibri"][size="3"][font="Calibri"][size="3"][/font][/font][font="Calibri"][size="3"]-[/font][font="Calibri"][size="3"]This is a quick and dirty starting point written in a couple hours; its purpose is to give you a starting point that you can either take and write your own or build on to.[/font]
[font="Calibri"][size="3"]-[/font][font="Calibri"][size="3"]This is a very BASIC implementation, meaning it is very limited such as it does not handle chained together method calls etc. I needed something with the ability to move elements around at runtime for design purposes and that is what this achieves. [/font]
[font="Calibri"][size="3"]-[/font][font="Calibri"][size="3"]You can download a sample solution at the end of the article to see it in action.[/font]
[font="Calibri"][size="3"]-[/font][font="Calibri"][size="3"]The sample you have to manually close the scripting window because I did not look into tying the rest of the tear down method to timeout the Console.ReadLine().[/font]
[font="Calibri"][size="3"]-[/font][font="Calibri"][size="3"]There is also a video included to show it in action[/font]
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[font="Calibri"][size="3"][/font][subheading]Back history:[/subheading][/font]
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[subheading]Quick, what is command based scripting:[/subheading][/font]
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[subheading]Technique:[/subheading]
[/font][font="Calibri"][size="3"]-[/font][font="Calibri"][size="3"]Have a system of receiving input running either externally or internally, in its own thread.[/font]
[font="Calibri"][size="3"]-[/font][font="Calibri"][size="3"]Take the commands input to said system and send them to a parser.[/font]
[font="Calibri"][size="3"]-[/font][font="Calibri"][size="3"]The parser determines if we are running a high level command such as getValue or help or a command against a registered object.[/font]
[font="Calibri"][size="3"]-[/font][font="Calibri"][size="3"]If the command is high level, it simply executes[/font]
[font="Calibri"][size="3"]-[/font][font="Calibri"][size="3"]If the command is against a registered object, we first have to find our registered object via the reference name specified on creation.[/font]
[font="Calibri"][size="3"]-[/font][font="Calibri"][size="3"]Once we find the object, we pass the registered object the input and it is parsed again to determine if it is a method or property.[/font][size="3"][font="Calibri"][size="3"][font="Arial"]-[/font]Then it is further parsed to determine if parameters were specified such as: test.Position = Vector2(10,10)[/font][font="Calibri"][size="3"]-[/font][font="Calibri"][size="3"]Once a command and its parameters (if any) are found, the command is executed.[/font]
[font="Calibri"][size="3"]-[/font][font="Calibri"][size="3"]Now you need to design error handling so that if you put in an invalid command it will not crash your game (defeats the purpose of on the fly changes) and it will provide useful feedback as to WHY the command was invalid.[/font]
[font="Calibri"][size="3"]-[/font][font="Calibri"][size="3"]Now that you have your scripting system in place, just wrap everything about scripting in like the below example to ensure it only runs on WINDOWS and in DEBUG mode;[/font][font="Calibri"][size="3"]
protected override void LoadContent() {

// Create a new SpriteBatch, which can be used to draw textures.

spriteBatch = new SpriteBatch(GraphicsDevice);

this.spriteFont = Content.Load("SpriteFont1");

this.text = new Test("Foo bar", new Vector2(100f,100f));

#if WINDOWS

#if DEBUG

// register objects

ScriptManager.getInstance().registerObject(this.text, "text");

Thread consoleInputThread =

new Thread(new ThreadStart(listenForInput));

consoleInputThread.Start();

this.running = true;

#endif

#endif

}



#if WINDOWS

#if DEBUG

private void listenForInput() {

string input;

do {

Console.Write(">>");

input = Console.ReadLine();

ScriptManager.getInstance().handleInput(input);

} while (running);

}

#endif

#endif



[size="3"][font="Calibri"][subheading]Programmers speak:[/subheading][/font]
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[font="Calibri"][size="3"][subheading]Video:[/subheading][/font]
[subheading]Example program download (Written in Visual Studio Express 2010 with Game Studio 4):[/subheading][/font]


Thank you for reading my blog entry on XNA 4.0 Scripting and I hope you found it interesting, helpful and most importantly; understandable.
Thanks, XXChester



**EDIT** Fixed the link and changed to mediafire because not only did my link become broken, rapdishare actually deleted my file as well. I am still working with admins to figure out why I cannot just attach the source here to avoid the third party software. Also please note that I deleted the old .rar I had saved off my desktop so this one is a bit different because it has some enhancements (such as automatic closing of the window on destruction) and the start of some rework(should all be commented out). This example should however still work. I also embedded the YouTube video.

Thanks again.

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