Clearing the browser cache of the Unity Web Player

For my current Unity web project, I am downloading scenes as AssetBundles hosted on my server, and now I have found myself constantly uploading the updated scenes whenever I make these (constant) changes.

Problem is, when I try the game online to see how the downloaded scene looks, my main game file which is downloading these scenes keeps on using the cached scenes from before.

That's because I am downloading the AssetBundles using WWW.LoadFromCacheOrDownload

To clear the cache, just head on over to http://unity3d.com/webplayer_setup/setup-3.x/ where you will see something like this:


And from there, you can simply delete the cache, or even make sure that while you're still working on the game, don't keep a cache at all.

Showing a Kongregate user's avatar image in a Unity 3D game

I decided that the game I'm currently working on is going to be tied to Kongregate, and since I'm doing that, might as well try to use as many features of the API as I can.

One of the features I'm trying to integrate in my game is the ability to render a Kongregate user's avatar in the game itself. For this tutorial, I will be using Kongregate's JSON REST API to fetch user data.

After skimming through the Kongregate API documentation, I found the page about the user-info REST call.

The url for a user-info call is formatted as follows: http://www.kongregate.com/api/user_info.json?username=<username> where username is obviously the username for the user account you're searching for.

This provides you with a response such as the following:

{
   "friends":[],
   "muted_users":[],
   "friend_ids":[],
   "muted_user_ids":[],
   "user_id":3590097,
   "username":"agnt666",
   "private":false,
   "page_num":1,
   "num_pages":1,
   "success":true,
   "user_vars":{
      "username":"agnt666",
      "level":3,
      "points":165,
      "avatar_url":"http://cdn4.kongcdn.com/assets/resize-image/50x50/assets/avatars/defaults/ant.png",
      "chat_avatar_url":"http://cdn4.kongcdn.com/assets/resize-image/16x16/assets/avatars/defaults/ant.png",
      "developer":false,
      "moderator":false,
      "admin":false,
      "gender":"Male",
      "age":25,
      "game_title":"Typocalypse 3D",
      "game_url":"http://www.kongregate.com/games/agnt666/typocalypse-3d"
   }
}

And the above response provides me with what I needed; the avatar url:

"avatar_url" : "http://cdn4.kongcdn.com/assets/resize-image/50x50/assets/avatars/defaults/ant.png"

Getting the avatar url in C#

Getting the username of the current Kongregate logged-in user is beyond the scope of this post (TODO: maybe in another one), so for this code I'm assuming you already have it.

public UITexture kongregateTexture;

IEnumerator FetchUserDetails(string username) {
    // Build the url for the REST call
    var detailsUrl = String.Format("/api/user_info.json?username={0}", username);

    // Do the call 
    var www = new WWW(detailsUrl);

    // ...and wait until we get back a response
    yield return www;

    // Get the JSON response text
    var responseText = www.text;

    // Deserialize it into a statically typed object to read to be able to read it's contents
    // For this demo, I'm using this JSON deserializer script: https://raw.github.com/gist/1411710/MiniJSON.cs
    var deserialized = MiniJSON.Json.Deserialize(responseText) as Dictionary<string,object>;

    //// TODO: a null check would be nice here

    // Get the user_vars object
    var userVars = deserialized["user_vars"] as Dictionary<string,object>;

    // Read the avatar url
    var avatar_url = user_vars["avatar_url"].ToString(); // http://cdn4.kongcdn.com/assets/resize-image/50x50/assets/avatars/defaults/ant.png

    //// Do the same routine to fetch the image
    var wwwAvatar = new WWW(avatar_url);
    yield return wwwAvatar;

    // And now we have the texture!
    Texture2D avatarTexture = wwwAvatar.texture;

    // Render the texture (I'm using an NGUI SimpleTexture widget)
    kongregateTexture.mainTexture = avatarTexture;
}

And this is the result with a shitty border I made around it:

Possible exception: Security Exception: No valid crossdomain policy available to allow access

Notice that in the above code, to build the url of the REST call, I used Kongregate's relative url: "/api/user-info.json...".

If I had used this instead String.Format("http://www.kongregate.com/api/user_info.json?username={0}", username);, I would have received this exception when running the game and looking at the debug log (console):


This error is thrown when reading the text field of the WWW instance (get_text).

So be very careful about that when doing the REST calls; always use relative urls! ...and this of course works because the game is hosted on http://www.kongregate.com.

Auto-Generating generic Tuple classes with T4 in C#

And yet again, here's another perfect example for using the T4 code generation toolkit in Visual Studio.

For a recent project, I wanted to use the Tuple class provided in the .NET Framework...problem was, I was stuck with .NET 3.5 and the Tuple class was introduced in version 4 of the framework. So, instead of writing a single Tuple class by hand (which would have been very trivial to do), I decided to write a T4 template which would generate all the Tuple classes I needed automatically.

The template itself is very trivial and the number of Tuple classes it generates is dependent on the value that I specify in the max variable at the top of the template.

For each of the Tuple classes the template generates, it creates a contructor which accepts all of the properties that the tuple will contain and also the actual properties that will be accessed from the outside.

Here's an example of what the template autogenerates for me when using max = 3 (granted, the first class it generates is a bit pointless but that can be easily omitted from within the template if it bothers you):

namespace FunWithTuples
{
    /// <summary>
    /// Represents a 1-tuple
    /// </summary>
    public class Tuple<T1>
    {
        public T1 Item1 { get; set; }

        public Tuple(T1 item1) 
        {
            Item1 = item1;
        }
    }

    /// <summary>
    /// Represents a 2-tuple
    /// </summary>
    public class Tuple<T1, T2>
    {
        public T1 Item1 { get; set; }
        public T2 Item2 { get; set; }

        public Tuple(T1 item1, T2 item2) 
        {
            Item1 = item1;
            Item2 = item2;
        }
    }

    /// <summary>
    /// Represents a 3-tuple
    /// </summary>
    public class Tuple<T1, T2, T3>
    {
        public T1 Item1 { get; set; }
        public T2 Item2 { get; set; }
        public T3 Item3 { get; set; }

        public Tuple(T1 item1, T2 item2, T3 item3) 
        {
            Item1 = item1;
            Item2 = item2;
            Item3 = item3;
        }
    }
}

---

And this is the full T4 Template:

<#@ template debug="false" hostspecific="false" language="C#" #>
<#@ assembly name="System.Core" #>
<#@ import namespace="System.Linq" #>
<#@ import namespace="System.Text" #>
<#@ import namespace="System.Collections.Generic" #>
<#@ output extension=".cs" #>

<#
var max = 3; // The total number of classes to generate
#>
namespace FunWithTuples
{
<#
max += 1;
for (var i = 1; i < max; ++i) {
#>
    /// 

    /// Represents a <#=i#>-tuple
    /// 
    public class Tuple<#=GetGenericTypesSignature(i)#>
    {
<#
for (var j = 1; j < i + 1; ++j) {
#>
        public T<#=j#> Item<#=j#> { get; set; }
<#
}
#>

        public Tuple(<#=GetConstructorArguments(i)#>) 
        {
<#
for (var j = 1; j < i + 1; ++j) {
#>
            Item<#=j#> = item<#=j#>;
<#
}
#>
        }
    }

<#
}
#>
}
<#+
    public string GetGenericTypesSignature(int total) {
        return String.Format("<{0}>", String.Join(", ", Enumerable.Range(1, total).Select(n => "T" + n).ToArray()));
    }

    public string GetConstructorArguments(int total) {
        return String.Join(", ", Enumerable.Range(1, total).Select(n => String.Format("T{0} item{0}", n)).ToArray());
    }
#>

Absolute value bars for fractions in LaTeX

The simplest way on how to include |absolute value| bars in LaTeX is to use the this notation: \left| and \right|.

Here's an example:

y = \left|\frac{1}{x}\right|

And that would be rendered as:

Common CIL incantations

Since I recently decided to try my hand at CIL by writing assemblies by hand, I'm now writing this post where I will list down a couple of basic CIL routines.

I am of course primarily writing this post for myself so that future me will have a reference if he (I?) decides to do something with it again.

Hello World

.assembly helloworld {}
.assembly extern mscorlib {}

.method public static void Main () {
    .entrypoint
    ldstr "Hello World!"
    call void [mscorlib]System.Console::WriteLine(string)
    ret
}

Including external assemblies

.assembly extern mscorlib {}

Pushing a 32 bit integer constant to the stack

ldc.i4 42

Pushing a 64 bit integer constant to the stack

ldc.i8 829190

Pushing a string constant to the stack

ldstr "Andreas"

Declaring and loading unnamed variables (popping elements off the stack)

.locals init (int32, string) // init specifies that the variables must be initialized to the default types
ldc.i4 42
stloc.0 // storing the 32 bit integer at position 0 by popping it off the stack
ldstr "CIL"
stloc.1

Defining a class

.class MathHelpers extends [mscorlib]System.Object {
    .method void .ctor() { // Constructor
        ldarg.0
        call instance void [mscorlib]System.Object::.ctor()
    }

    .method public instance int32 Inc(int32) { // Instance method; the instance keyword can be omitted
        ldarg.0
        ldc.i4.1
        add
        ret
    }
    
    .method public static int32 Add(int32 n, int32 m) {  // Static method
        ldarg n
        ldarg m
        add
        ret
    }
}

Invoking methods from external assemblies

.assembly extern mscorlib {}

// ...

ldstr "Writelining"
call void [mscorlib]System.Console::WriteLine(string)

Invoking an instance method

.locals init (class MathHelpers mh)

newobj instance void MathHelpers::.ctor()
stloc mh

call instance void MathHelpers::Show()

Invoking a static method

call void MyNamespace.MyClass::StaticMethod()

Using an array

.locals init (string[] names);

.ldc.i4.4 // the int32 constant that's used for the size of the array: new string[4]
newarr string
stloc names

// Add element 0
ldloc names
ldc.i4.0 // array index
ldstr "Dreas"
stelem.ref

// Add element 1
ldloc names
ldc.i4.1 // array index
ldstr "John"
stelem.ref

Adding a line break for IntelliSense in XML documentation comments

This is a quick post on how to insert a line break for XML documentation comments in C#.

The easiest way I've found is to use a non breaking space (ASCII code 255) in combination with the paragraph tags: <para>

To insert the non breaking space, press ALT + 255 (from the numeric keypad).

Here's an example:

/// <summary>
/// <para>This method does everything.</para>
/// <para> </para>
/// <para>...and I mean everything.</para>
/// </summary>
private void DoEverything() {

And this is how it looks in IntelliSense:

Preventing Vim from automatically inserting line breaks

I recently had a very frustrating issue with Vim where it was inserting a line break automatically for me whenever a line exceeded the 80 character mark.

After some searching around, I realized that I had textwidth (tw) set to 79 in my _vimrc file. From the documentation:

textwidth.
Maximum width of text that is being inserted. A longer line will be broken after white space to get this width. A zero value disables this.

So as you can see from the documentation, fixing it was very trivial: set tw = 0