2D Basics

Using Unity for 2D games

• Manual: 2D or 3D
• Manual: 2D and 3D Mode settings
• Manual: 2D Game Development Quickstart Guide
  • Manual: Initial Setup for 2D Games
• Unity is first and foremost a 3D engine (x, y, z)
  • there is no dedicated 2D (x, y) mode
• There is a dedicated Vector2 class for 2D vectors
  • Some vectors used in 2D, like transform are still Vector3

2D Project template

• When creating a new project, you can choose a 2D project template
• IT'S STILL SECRETLY 3D, the z axis is just disregarded
• It basically just adjusts the Unity UI
  • some 2D GameObject templates, like sprites and tilemaps available
• You can change between 3D and 2D view modes by pressing the 2D button in the Scene view

Useful 2D GameObjects

• Sprites
  • Manual: Sprites
  • See Sprite Renderer component
• 2D Primitives
  • For drawing basic shapes in 2D
  • Manual: 2D Primitives
• Sprite Shape Asset
  • Curve-based graphics & collision
  • Manual: Sprite Shape

Camera component

• 2D camera needs to be orthographic
  

Collision & Physics components

• Colliders
  • See: Collision
  • Remember to use the 2D versions of colliders:
    • PolygonCollider 2D, CircleCollider 2D, ...
• RigidBody 2D
  • See: Physics
• Effectors
  • Manual: Effectors 2D

Sprite Renderer component

• 2d images in games are called sprites

• They're drawn on screen with the Sprite Renderer component

  

Example: Using Sprite Assets

1. Create a .png image file
2. Add it to your Assets folder
3. Click it once to see its properties in the Inspector. Set the values:
   • Set Texture type to Sprite (2D and UI)
   • Pixels per unit value tells how big the sprite should be on screen
   • If you're using pixelart, you need to take some more things into consideration
     • See: Pixelart in Unity
   • Click Apply
4. Drag it from the Project window into the Sprite field in the Sprite Renderer component

Other renderer components

• Line Renderer
  • Use for drawing a line on screen
  • Manual: Line Renderer
• Trail Renderer
  • For drawing trails
  • Manual: Trail Renderer
• Sprite Shape Renderer
  • Draw images along a path, or just paths
  • Sprite Shape Renderer

Extra: Two ways for 2D shooting

• Brackeys video: 2D shooting
• For slow bullets: Instantiate a bullet prefab
• For instant hit: Raycasting (see example below)

  RaycastHit2D hit = Physics2D.Raycast(line.transform.position,
    line.transform.up,
    lineDistance);
  

Extra: Moving on a grid

For grid-based movement, see this thread: Unity answers: Moving on a grid