Maedi Prichard

Unity Cheatsheet

2019-06-07T00:00:00+00:00

Unity lets you make games of any kind for any platform. It’s revolutionary but its flexibility can lead to a system which is hard to understand. Here’s what I learnt making my game as a handy reference.

Cheatsheet

Which building blocks do I use and when?

	GameObject	ScriptableObject	MonoBehaviour	No inheritance
What	The entities that interact with each other.	Data models editable via Unity UI.	`GameObject` actions and data flow.	Basic C# class.
When	If it can be seen in the game world.	To define the settings of `GameObject`s and general configuration.	To control `GameObject`s, generate and handle events.	When behaviour not directly related to a `GameObject`.
Where	Lives in the Hierarchy.	Lives in the ProjectView. Initialized by Unity.	Attached to `GameObject`s as a Component, or lives in the Hierarchy.	Lives in the ProjectView. Called programatically by other scripts.
Example	`Scene.unity`	`Config : ScriptableObject`	`PlayerController : MonoBehaviour`	`SaveController`
Use Cases	Player Camera Scene	Player Config	Player Camera Scene	Saves User Input Utilities

Accessors

In Unity most things are GameObjects which scripts are attached to. In your scripts you can access most things with these 3 snippets:

Get the instance of the script/class we’re in with this.
Get the GameObject the script is attached to with this.gameObject.
Get the GameObject’s components with GetComponent<ComponentName>().
The longer version this.gameObject.GetComponent<ComponentName>() will also work.

If you’re searching for GameObjects in the Scene Hierarchy:

Find a GameObject by name: GameObject.Find("name")
Find a GameObject of a certain type: GameObject.FindObjectsOfType(typeof(MyType));
Find a GameObject with a certain tag: GameObject.FindGameObjectsWithTag("MyTag");

Debugging

Using breakpoints via Visual Studio is the best way to debug complex data flows, but sometimes you just want good old fashioned debugging.

List components and all their variables

Put using System.Reflection; at top of file then paste:

Component[] components = (Component[]) GetComponents (typeof(Component));
foreach (Component c in components) {
  Debug.Log("Name: " + c.name + " Type: " + c.GetType() + " BaseType: " + c.GetType().BaseType);
  foreach (FieldInfo field in c.GetType().GetFields()) {
    System.Object obj = (System.Object) c;
    Debug.Log("Name: " + field.Name + " Value: " + field.GetValue(obj));
  }
}

Shortcuts

You will need to keep running the main scene and navigating to it in Unity then running it is tedious. Create a keyboard shortcut instead with:

using UnityEditor;
using EditorSceneManager = UnityEditor.SceneManagement.EditorSceneManager;

public static class PlayMainMenu {
  // Add keyboard shortcut.
  [MenuItem("Edit/Play Main Menu _m")]
  public static void PlayFromPrelaunchScene() {
    if (EditorApplication.isPlaying) {
      EditorApplication.isPlaying = false;
      return;
    }
    EditorSceneManager.SaveCurrentModifiedScenesIfUserWantsTo();
    EditorSceneManager.OpenScene("Assets/Scenes/<scene-name>.unity");
    EditorApplication.isPlaying = true;
  }
}

Replace <scene-name> with the name of your scene. Now M key on your keyboard will run the main scene from anywhere.

Send email from your custom domain for free (Gmail, Mailgun, Cloudflare)

2018-12-17T00:00:00+00:00

A recipe for setting up your email address at your custom domain for free. Using Gmail, Cloudflare, Mailgun and optionally Mailchimp.

Mailgun

Create an account then verify it. You need to add a credit card to get all of the features, but it’s still free for the first 10,000 emails a month.

Add domain

Go to Domains:

Click “Add Domain” button
Under “Domain Name” enter your domain (ex: example.com) Ignore the message “We highly recommend using a subdomain”. You should not include a subdomain if you want to receive email too.
Submit the form

Forward email to Gmail

Go to Routes:

Click “Create Route” button
Set “Expression Type” to “Match Recipient”
Set “Recipient” to your email address (ex: info@example.com)
Under “Actions” check “Forward” and add your Gmail address (ex: example@gmail.com)
Submit the form

Cloudflare

Get config from Mailgun

In Mailgun go to your domain (ex: https://app.mailgun.com/app/domains/example.com). Keep this page open as you will be copying and pasting values from here to Cloudflare.

Configure DNS

In Cloudflare go to the DNS section.

Add the 2 TXT records using their supplied values. (ex: v=spf1 include:mailgun.org ~all and k=rsa)
Add a CNAME record with “email” as the “Name” and mailgun.org as the “Value”.
Uncheck the cloud icon for the CNAME.
Add an MX record with your domain as the “Name” and “mxa.mailgun.org” as the “Value” and a “Priority” of “10”.
Add an MX record with your domain as the “Name” and “mxb.mailgun.org” as the “Value” and a “Priority” of “10”.

In Mailgun click the “Check DNS Records Now” button to confirm settings are correct.

Gmail

Go to Gmail:

Click the “Cog” icon and go to Settings
Click the “Accounts and Import” tab.
Under “Send mail as” click “Add another email address”:
- Set “Name” to your personal or company name
- Set “Email address” to your email address (ex: info@example.com)
- Ensure “Treat as an alias” is checked
Click “Next Step” button
Fill in the form with settings from you domains “Domain Information” at Mailgun.
- Gmail’s “SMTP Server” equals Mailgun’s “SMTP Hostname”
- Gmail’s “Username” equals Mailgun’s “Default SMTP Login”
- Gmail’s “Password” equals Mailgun’s “Default Password”
- Ensure “Secured connection using TLS” is checked
Click “Add Account” button
You should receive a message like: “Congratulations, we successfully located your other server and verified your credentials.”
Verify your new email address in Gmail

Mailchimp (optional)

In Mailchimp add your domain at Account -> Domains:

Click “Verify A Domain”
Under “Email Address” enter you email address
Go to Gmail and click the verification link

In Cloudflare add these records:

Add a CNAME record with k1._domainkey.example.com for “Name” and dkim.mcsv.net for “Value”.
Add a TXT record with example.com for “Name” and v=spf1 include:servers.mcsv.net ?all for “Value”.

In Mailchimp at Account -> Domains:

Click “Authenticate” button to the right of your domain.

Host Your Git And Deploy It Too!

2018-09-04T00:00:00+00:00

After the rise of cloud hosting with their multiple environments and slick UIs it’s easy to forget why we started using them in the first place… Git. What if I told you can put Git on any old server? That you can still host sites yourself and deploy code to production with a simple git push? Yes, you can have (host) your cake (git) and eat (deploy) it too.

1. Create the user

A requirement of this method is that the Git user and the Unix user who owns the web accessible directory are the same account. With this structure in place we can work our magic.

We will connect to this user when we push changes up from our local. Create this user like you would any other user on a Unix machine:

sudo adduser <username>

Add the sudo and ssh groups to this user:

usermod -a -G ssh <username>;
usermod -a -G sudo <username>;

2. Give remote user your public key

SSH to the remote server as the <username> user. In their home directory:

mkdir ~/.ssh && chmod 700 ~/.ssh;
touch ~/.ssh/authorized_keys && chmod 600 ~/.ssh/authorized_keys;

On your local machine copy the contents of your public key which is usually found at:

~/.ssh/id_rsa.pub

Back on the server paste your public key into authorized_keys:

nano ~/.ssh/authorized_keys

3. Create a bare Git repo

A bare git repo just means that only the “.git” folder exists in the repo’s folder, not the tracked files. The bare git repo becomes the central “host” for the files. This host will then export the tracked files to our web accessible destination directory.

Create a bare repo in your remote user’s home directory:

mkdir .git;
cd .git;
git init --bare;

Note: Though you’ve created this repo in ~/ it will not try to track the contents of your home directory.

4. Push to the bare repo

Add the bare repo “host” as the remote on your local repo:

git remote add origin <username>@<server>:/home/<username>/.git

In the example above <server> is either the server’s IP address or a domain that points to it.

5. On push export to destination directory

On the remote server add a post-receive hook:

nano ~/.git/hooks/post-receive

Paste:

#!/bin/bash
while read old new ref
do
  if [[ $ref =~ .*/master$ ]];
  then
    echo "Deploying master..."
    git --work-tree=/home/<username> --git-dir=$PWD checkout -f
  else
    echo "$ref received but not deployed."
  fi
done

This script will export Git’s working tree (the tracked files) to /home/<username>. Replace <username> with your destination directory. In my case my repo contains a docroot folder which will be web accessible via Apache, so I have no issue exporting the tracked files directly into my user’s home directory.

Note: As mentioned at the start of the tutorial, the destination directory has to be owned by the Git user in order for Git to have permission to create files and folders. This is why we’re exporting within the user’s home directory.

Save file with Control/Command + O and exit nano with Control/Command + X then make the script executable:

chmod +x ~/.git/hooks/post-receive

Save the file and we’re almost done!

Making a deployment

To test things out simply add a dummy commit to your local repo, then git push. Now when the base repo receives the push it exports the latest tracked files to the /home/<username> destination directory. Visit your website’s URL to see the changes!

File System permissions

We’re only human and you’ve likely uploaded files and folders already that are owned by the wrong users and groups. The post-receive hook will only be able to modify files and folders under the control of <username>. So if you git push and something’s not updating then chances are that file/folder is owned by another user.

Find incorrectly owned directories with:

ls -al

Then change the owner and groups of folders and their children with:

chown -R <user>:<group> <directory-path>

Done!

This is my method. If you have any improvements please let me know.

Jekyll: Dynamically Filter By Date

2018-04-09T00:00:00+00:00

Jekyll produces static HTML… but what if we want to filter content by the current date? Say we have a list of events and want to hide past events. The following 2 options have you covered.

Static liquid filter

Use this in your template to filter posts by current date:

{% capture now %}{{'now' | date: '%s' | plus: 0 %}}{% endcapture %}
{% for post in site.posts %}
  {% capture date %}{{post.date | date: '%s' | plus: 0 %}}{% endcapture %}
  {% if date > now %}
    <!-- post content here -->
  {% endif %}
{% endfor %}

This code captures the current time (at build time) into the now variable and only shows the post if its date is larger than now (in the future). The date: '%s' filter captures the post’s date as a timestamp and plus: 0 ensures that any string values are cast to integers. (Method from Stack Overflow).

Of course this filtering still only happens whenever Jekyll is built…

Dynamic javascript filter

jQuery Date Filter is a little javascript library which filters out items by date on the client-side. So if your static site hasn’t been rebuilt in a while and is showing stale content, this library will hide it.

CSS Tricks

2017-11-28T00:00:00+00:00

Flex

Flex CSS columns with margin

Use this mixin when you want 3 columns + margin with flex!

// Flex columns using all the tricks.
@mixin three-columns() {
  $gutter-column: 10px;
  // Remove gutter.
  margin: -$gutter-column;
  ul {
    margin: 0;
    display: flex;
    justify-content: center;
    li {
      // Add gutter.
      margin: $gutter-column;
      // 3 columns including gutter.
      width: calc(33.3333333333333% - (#{$gutter-column} * 2));
    }
  }
}

Preload images via CSS

Browsers doesn’t preload images that show on hover, leading to an awful flicker as the new image loads. Preload the image via CSS to avoid this flicker:

body:after{
  display: none;
  content: url('<path>.jpg');
}

Jekyll: Check if string is a number

2017-10-01T00:00:00+00:00

How do you check if a string in Jekyll is actually a number? For example you might want to do one thing when a value is '123' and another when the value is 'ABC'. Jekyll doesn’t seem to provide a simple way to do this out of the box. Crazy that such a simple feature doesn’t exist!

I’ve come up with a method. The logic is to treat the string as if it were a number and see how it reacts. A string of letters cannot be added to, but a string of numbers can. plusing a string that’s not a number will return 0, while plusing a string that’s a number will return the original number.

Method

  
    <!-- Get the value. -->
    {% assign value = '123' %}
    <!-- Add the value. -->
    {% assign addition = value | plus: 0 %}
    <!-- Convert addition to string for comparison. -->
    {% capture addition %}{{addition}}{% endcapture %}

    <!-- Value is a number if addition has no effect. -->
    {% if value == addition %}
      <!-- Value is number. -->
    {% endif %}

Let me know if there’s a better way to do this!

This method seems pretty robust. Only integers and floats without other characters in the string are considered numbers. The value '0' is correctly identified as a number.

Semantic blockquotes in HTML5

2017-09-22T00:00:00+00:00

If you’re like me you’ve been doing blockquotes like this for years:

<blockquote>
  The quote...
  <cite>The author...</cite>
</blockquote>

Well it turns out <cite> isn’t what we thought it was. It doesn’t mean the source of the quote, it means the name of the source material that the quote is from (book, article, song). So it’s not the author or the company, it’s the publication. This just isn’t the right tag to use.

There’s also another problem; the <cite> is inside the <blockquote> tag, indicating that the author attribution is part of the quote itself. This is sad semantics :(

There’s got to be a better way?

Apparently the correct way to quote is like this:

<figure>
  <blockquote>
    The quote...
  </blockquote>
  <figcaption>The author...</figcaption>
</figure>

The quote is still a <blockquote> but this time there’s no <cite> inside. The author sits beneath as a <figcaption>, with both elements inside a <figure> tag.

This method basically borrows the logic behind how <img> tags are attributed. For images the structure is:

<figure>
  <img src="image.jpg">
  <figcaption>Fig 1: Description</figcaption>
</figure>

Basically the same thing.

Though there’s no true consensus, the <figcaption> method makes sense. It re-uses a structure that’s been around for a while that already means exactly what we’re trying to express; a thing that is attributed to another thing.

Some people like to replace <figcaption> with <footer>, which semantically means a similar thing. All in all I think this structure is a great improvement on something that’s always been bugging me about quotes in HTML.

Jekyll Tricks

2017-09-17T00:00:00+00:00

How to create an empty array

In your _config.yml initialize an empty array into a YAML property:

emptyArray: []

Then access that property in your Liquid template:

  {% assign my_array = site.emptyArray %}

You can push values into the array like so:

  {% assign my_array = my_array | push: 'value' %}

Get any item by its ID

The ID of any posts or collection item in Jekyll will be its filename. This is what you see in the URL as the item’s path (not including the parent path). For example a file called about-us.md with have the ID of about-us. With this ID in hand you can now embed any post/collection item anywhere by filtering for it:

  {% assign post = site.posts | where: "id", 'about-us' | first %}

String concatenation

Append method:

  {% assign new_var = var_first | append: ' - ' | append: var_second %}

Capture method:

  {% capture new_var %}{{ var_first }} - {{ var_second }}{% endcapture %}

Date formatting

Format a date by appending a date filter to your variable like this:

  {{post.date | date: '%Y %B %d' }}

Here are the docs and here’s a handy reference on %placholders.

SQL Tricks

2017-09-13T00:00:00+00:00

Import a database via command line

mysql -uroot -proot [existing-database] < ~/dev/[new-database].sql

Specifically ask for MAMP PRO mysql

MAMP/MAMP Pro is an application that runs a MySQL, Apache and PHP stack on Mac.

 /Applications/MAMP/Library/bin/mysql --host=localhost -uroot -proot

Get size of all databases

SELECT table_schema AS "Database name", SUM(data_length + index_length) / 1024 / 1024 AS "Size (MB)" FROM information_schema.TABLES GROUP BY table_schema;

Get size of all tables in a database

SELECT
  table_schema as `Database`,
  table_name AS `Table`,
  round(((data_length + index_length) / 1024 / 1024), 2) `Size in MB`
FROM information_schema.TABLES
ORDER BY (data_length + index_length) DESC;

UNIX Tricks

2017-09-12T00:00:00+00:00

File System

List directory tree:

tree -df .

List directory tree with full paths:

find . -type d

List the actual size of each directory/file within a directory:

du -sh */ | sort -n

List all files bigger than 100MB for the entire disk:

du --all --one-file-system / | awk '{if($1 > 102400) print int($1/1024) "MB" " " $2 }'

Encoding

Convert the charset of a file to UTF-8

iconv -f [old-charset] -t utf-8 [old-filepath] > [new-filepath]

Find non-ASCII characters in a text file

Linux:

grep --color='auto' -P -n "[\x80-\xFF]" file.txt

Mac OS X:

brew install pcre
pcregrep --color='auto' -n "[\x80-\xFF]" file.txt

You may need to increase your buffer with --buffer-size=999999999. – Source

Backups

Download a copy of a directory to a local directory:

rsync --dry-run --archive -vv --stats --progress <source> ~/dev/<destination>

rsync -chavzP --stats user@remote.host:/path/to/copy /path/to/local/storage