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Unity is a cross-platform game engine used to develop video games for PCs, consoles, mobile devices and websites. The latest version (Unity 5) shipped with a WebGL exporter which means that developers can publish their games to the web with ease. As the name suggests, The WebGL exporter takes advantage of WebGL, a JavaScript API for rendering interactive 3D computer graphics and asm.js, the Mozilla-developed subset of JavaScript that's touted as an "assembly language for the web". You can read more about Asm.js and WebGL for Unity and Unreal Engine here.
In this tutorial I'm going to show you how to get up and running with Unity. I'll also show you how to how to create a simple game in Unity using JavaScript and how to export your game to the web.
You can check out the finished game here (you'll need a WebGL-capable desktop browser), or you can download both the game files and the project files from our GitHub repo.
So let's get started …
A Word About JavaScript in Unity
When we talk about JavaScript in Unity, we are actually talking about UnityScript, which is something of a typed JS dialect. Unity themselves often refer to this JavaScript, yet more cynical observers think that "Unity does JavaScript" is something of a marketing ploy. Either way, we should be clear about the fact that UnityScript does not conform to any ECMAScript specification — nor does it try to. You can find a good overview of the differences here.
Installing Unity
To start this tutorial, we need to have a running Unity version, that can be downloaded here. Unity has installers for Windows and Mac OS X. Linux users can possibly run Unity via Wine, but your mileage may vary.
After installation, we're good to go! So let's open Unity and create a new 3D project.
The Project Setup
Once Unity opens for the first time, we should take a minute to find our way around the main window:
- The leftmost panel is the Hierarchy, which outlines all the elements in the current scene. A scene is something like a view of the game, e.g. a level or the menu. At the moment there should be a Main Camera element and a Directional Light element.
- In the middle is the Scene view, illustrating the camera and light in 3D space with icons.
- There is a Game tab next to the Scene tab, showing the game itself, as it would be seen by a player. This is made for testing the game in the editor.
- On the right-hand side there is the Inspector panel, where element settings may be modified. Let's try it out by clicking on Directional Light in the Hierarchy. We should now see lots of information about this light and be able to turn off its shadows with Shadow Type: No Shadows.
- At the bottom is the Project window, which displays a view of the files we need to develop our game.
Now that we are familiar with Unity's interface, there is one thing left to do, before beginning with the development: save the current scene. File > Save Scene opens a Save Scene dialog that leads to a folder called Assets
. One common way to organize files in Unity is with subfolders. So add a new folder to the Assets
folder named Scenes
and save the scene in this folder with the name Level.unity
.
Create a Hero
Our game will consist of a hero, jumping higher and higher from platform to platform. If it misses one and falls into oblivion, the game will be lost. So let's start by creating the hero. Because a player will see the game from a first-person perspective, the hero's appearance doesn't really matter and we can use standard sphere geometry. The benefits of a sphere are that it may be created in few steps and that it suits the physics we need for jumping. Add the sphere by clicking Create in the Hierarchy and edit the following properties with the Inspector:
Position { X: 0, Y: 2.5, Z: 0 }
Scale { X: 0.3, Y: 0.3, Z: 0.3 }
Let's test what we've done by pressing the play button. We should see a sphere in 3D space in front of a skyline.
To make the hero fall, it has to gain weight. Thus we need to add a component to the sphere by clicking the corresponding button in the Inspector and selecting Rigidbody. And since we do not want the hero to rotate, we freeze it in the Rigidbody
component by opening Constraints and selecting all the axes in the Rotation row. When playing the scene again, we should be able to watch the hero fall.
To save the hero from a never-ending fall, we will create a flat box that serves as a platform. For that, we have to add a cube and set the Scale.Y
value to 0.1
. Replaying the scene confirms that the hero lands safely on the platform, although I must admit that it doesn't really look natural. So how do we get the hero to bounce? By adding some physics materials.
Make the Hero Bounce
First of all, we need to create a new physics material for the sphere to make it bouncy. To do this create a new folder in the Assets
folder called Materials
and in here create a new physics material. Let's call it Bouncy_Sphere
. The values we need to adjust in the Inspector are:
Dynamic Friction: 10
Static Friction: 10
Bounciness: 1
Friction Combine: Maximum
Bounce Combine: Maximum
If we add this material to the Sphere Collider, this will make the sphere bounce up and down, but always to an equal height. To make the sphere jump higher and higher with each single bounce, we have to add some physics material to the platform too. For this, we create another material called Bouncy_Platform
and change its values to:
Dynamic Friction: 0.9
Static Friction: 0.9
Bounciness: 1
Friction Combine: Average
Bounce Combine: Multiply
To achieve consistency here, we should also rename the cube element to Platform
, by clicking on it twice in the Hierarchy. When we start the game now, we can notice that the sphere jumps higher and higher each time.
We will also create a new standard material called Platform
to give the platform some color. After creating this material, use #C8FF00
as the Albedo color (Albedo
is the label in the Unity UI) and then drag and drop this material onto the platform element. It should now be yellow.
Add a First-person Perspective
To add a first-person perspective, we drag and drop the camera (in the Hierarchy) onto the sphere. This will make the camera a child element of the hero and cause the camera to follow the sphere while it's moving. The camera properties also have to be adjusted to:
Position { X: 0, Y: 1, Z: 0 }
Rotation { X: 90, Y: 0, Z: 0 }
Scale { X: 2.5, Y: 2.5, Z: 2.5 }
Clear Flags: Solid Color
Background: #000
Field of View: 80.3
We will also create a spotlight as second child of the sphere. This will give the player a sense of the hero's current jumping height. Adjust the values of the spotlight to:
Continue reading %Creating a WebGL Game with Unity 5 and JavaScript%
by Michaela Lehr via SitePoint
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