Module 5 Examples: Unity Specific Tools
Link to GitHub
Coverage
Unity specific skills you will need,
practice, and demonstrate include:
·
Platformer
support: RigidBody2D::Dynamic
·
Near-term
fixed number periodic actions: Coroutines
·
Templated
graphical interface to data: Scriptable Objects
·
TilePallete and Tilemap: for
creating (by painting) levels
·
Particle
Systems: beginning of creating effects
Concepts
you will explore and understand include
·
Nothing
much here, mostly simply about how to use Unity to accomplish specific tasks
- Support for Platformers:
- Run Behavior:
- D: slides towards the right
- Watch out can move right movement is only possible on the ThePlatform (upper Brown platform) or in the air
- CANNOT move right on TheFloor (Black platform)
- This is awkward to control and no fun, but makes the point that you can have different behaviors on different (types of) platform
- A: moves the left
- W: strange seemingly wanting to jump
- Space: flies upwards
- Make sure to look at the Console print out: differentiate “Collision” from “Trigger”!!
- Brown(ThePlatform)/Black(TheFloor)/Orange(StationaryObsticle): Simple platforms
- White (Collide-And-Overlap): Only detects collision (allows overlap)
- Pink (Collide-And-Push): Detects and maintain collision (no overlapping)
- Scene setup:
- Hero: simple Sprite with
- BoxCollider2D: (for collision detection)
- IsTrigger: is off, which means this is NOT just for detecting collision, it is more
- Try: switch on triggering and see the hero free falls
- When on: only interested in knowing there is a collision
- RigidBody2D: this object is the active party in collisions, this object collide with others
- Type: Dynamic (things moves under gravity now)
- Constraints: Freeze rotation in Z (object will _not_ rotate as a result of collision)
- HeroMovement: script, refer to the following
- Platforms: Brown/Black/Orange
- DO NOT have RigidBody2D, as not active collider. These objects are expected to be collided by other active objects (objects with RigidBody2D)
- Have: BoxCollider2D
- Collide-and-Overlap: White
- DO NOT have RigidBody2D
- BoxCollider2D:
- IsTrigger: set to On (only for detecting collision)
- That’s why Hero can detect when colliding with this object and can overlap
- Collide-and-Push: Pink
- BoxCollider2D:
- isTrigger: Off
- RigidBody2D:
- Type: Dynamic
- You can push the box
- Type: Kinematic
- The box stays stationary
- Scripts::HeroMovement
- mHeroPhysics: is reference to the RigidBody2D component
- SerializeField: Notice this keyword, allow private datatype access from the editor
- Update():
- A/W keys: tries to change position direction
- Notice: “W” key does not work well at all, fighting with the physics after first y-movement!
- Lesson: when Dynamic is on, changing position may not work (moving right seem to work as Physics is not operating when Hero is resting on platform)
- Space: changing the traveling velocity (goes back to zero because of gravity)
- D: only allows right-ward movement when touching the Brown platform or not touching anything (in the Default layer)
- OnCollision: Enter/Stay/Exit
- Collision with objects with Colliders’s IsTrigger set to OFF
- Default: Collide and stay (e.g., standing on platform) unless
- Push: other object has RigidBody2D, and type is Dynamic
- OnTrigger: Enter/Stay/Exit
- Will overlap: detecting a collision with no behavior assumption
- Learned:
- How to for a platformer with Collider2D and RigidBody
- Collider2D::IsTrigger:
- On: only triggers, objects will overlap
- Off: will trigger and with RigidBody::Dynamic-type, will push the object
- RigidBody
- Type: Dynamic for simulating gravitational physics
- Kinematic: for stationary
- Constraints: freeze relevant rotations in physics simulation
- Coroutines: Short term, fixed (usually) number periodic actions
- Same scene and control as above, the only thing interesting is the White block
- Run behavior:
- move the Hero to collide the White block from the left/right to see the block changing color
- Collide from the Right: White block blinks yellow/magenta
- Collide from the Left: White block goes through a series of color changes
- Scene Setup:
- Identical to above
- Recall that White block
- Does NOT have a RigidBody2D (not able to be actively colliding with another object)
- Does have a Collider2D with IsTrigger set to On
- Can report on collision (by OnTrigger-functions)
- Scripts::WhiteMagic on the White block
- mColorChanging: data type is Coroutine when not null, means White cube in color changing mode
- OnTriggerEnger: attempt to go into color changing mode
- OnTriggerExist: attempt to exit from color changing mode
- ColorChangeFromLeft/Right()
- Note the yield return statement ß this is where the function will yield execution until later
- EnterColorChageMode()
- rightFunc: data type is IEnumerator capable of holding the address of a function
- Calls StarCorotuine() to star either the left or the right color changing mode
- ExitColorChangeMode()
- Note: StopCoroutine(argument of Coroutine data type)
- Meaning, you can have many coroutines running and you can select specific one to stop
- StopAllCorotuines(): will stop every single coroutine
- WATCH OUT:
- Coroutine is run synchronously (e.g., at the end of the Update() calls of all exponents)
- This is powerful and can be confusing, and very importantly is VERY challenging to debug!
- Use with care, do not miss use.
- Reference: https://docs.unity3d.com/Manual/Coroutines.html
- Scriptable Objects: Templated graphical interface to data
- Run Behavior:
- D: slides towards the right
- A: moves the left
- Space: flies upwards
- Pay attention to the colors:
- White/Black/Red block:
- Collide from the left Blinks between two colors,
- Collide from right goes through a series of color changes
- Pink/Orange: When collide, spawns an egg at Hero location that behaves like a Red-Block
- Scene setup:
- Similar to above
- Take note of the Resources folder
- A Sprite: Egg
- ColorBlocks-folder: Three ColorBlock (these are ScriptableObject to be discussed)
- ScriptableObject/ColorsForBlock
- Think: MonoBehavior is for modifying behaviors, then, ScriptableObject is for providing data to the behavior
- How it works: Refer to ColorsForBlocks.cs
- Create a new C# class, subclass from ScriptableObject
- Take note of: [CreateAssetMenu() ]
- fileName: default file name
- menuName: what shows in create
- WARNING: if you change the argument-strings for these variables, you will probably have to re-start Unity
- Now, you can code any data you want to provide, in this case, defining the colors for the WhiteMagic behavior from previous example
- Notice, only providing data and no behavior and no modification to the data
- How to use:
- Now, in the Asset folder, you can create an instance of ColorsForBlock!! (RMB: Right-Mouse-Button)
- Think: ColorsForBlock is like a Sprite
- Egg: You create a new Sprite (by dragging in an image), rename the Sprite to Egg
- RedBlock: You create a new ColorsForBlock by RMB and rename the created
- Egg: drag to any GameObject::SpriteRenderer to provide the look of a new object
- RedBlock: drag to any ColorBlock to provide the colors for block color-changing
- Egg: if you change the image, ALL gameobject refer to Egg will change appearance
- RedBlock: if you change the colors in RedBlock, ALL ColorBlock referring to RedBlock will have different colors!
- The three Resources/ColorBlocks are three instances of ColorsForBlocks with modified color values
- These are data for ColorBlock-script
- Scripts::ColorBlock.cs
- This was the WhiteMagic.cs script, instead of defining the color data in code, now, it has a reference to the ColorsForBlocks, so,
- ColorBlock: defines the behavior without the actual color data
- ColorsForBlocks: defines the data
- Think:
- SpriteRenderer: defines how to show an image on a GameObject without the actual image
- Sprite: defines the image
- Notice:
- BlackBlock vs WhiteBlock vs RedBlock: they have very different colors defined
- The ColorBlock-White/ColorBlock-Red/ColorBlock-Black: these objects all have the same ColorBlock component, but the components are with different ColorsForBlocks, so, these gameObjects have the same behavior but different data.
- They all blinks, but blinks with different colors
- Scripts::DynamicBlock.cs
- Shows/Verifies: how to create a ColorBlock from scratch
- The Pink/Organge: blocks have this component
- References:
- Overview on the ideas behind ScriptableObjects: https://www.youtube.com/watch?v=PVOVIxNxxeQ
§
A step by step tutorial: https://www.youtube.com/watch?v=aPXvoWVabPY
- Tile
Palettes and Tilemap
- What:
- Create a level by painting it: three main topics
- Tile sprite sheet: this is like the color, choice of colors to be used in a painting
- Tilemap: this is like the canvas (target to be painted on)
- TilePalette: this is like the color to be painted on a canvas, in this case, a “color” is a selected tile from the tile sprite sheet
- Run Behavior:
- WASD and Space to control the HeroKnight
- Tile Sprite sheet:
- Turn a tile sprite sheet into individual sprites (usually with Auto Slicing)
- Remember: the size of each sprite element:
- Controlled/refined by Texture Pixels Per Unit
- TilePalette:
- To create TilePalette: (Windows -> 2D->TilePalette) https://docs.unity3d.com/6000.0/Documentation/Manual/tilemaps/tile-palettes/create-tile-palette.html
- Remember, this is for painting onto the Tilemap (to be discussed next), here is the UI
- Operations for this palette
- 1: Name of this palette (you can create many)
- 2: Operations to perform on this palette: To edit, grid on/off
- Operations for the Tilemap:
- 3: Which map to draw on
- 4: Mode of drawing: selecting area, moving area, select brush
- Tilemap:
- Unity help page: https://learn.unity.com/tutorial/introduction-to-tilemaps
- One grid system with many layers of maps
- Idea: each grid is to contain one tile-sprite (again, size of the tile-sprite is specified by the pixel-per-unit attribute on the original tile sprite sheet texture.
- Example paint operation:
- Tile sprite sheet sutup: Drag in your tile spritesheet, make Multiple, slice into individual tiles
- Open TilePalette, create the new palette using your tile sprite sheet
- Create a Tilemap object (will create with a Grid and one Map child): name the child Background
- Refine tile pixel size (this is what I do): paint a tile in the grid, adjust the tile sprite sheet Pixels Per Unit (or grid size) until each tile covers exactly one grid.
- Now, paint the Background
- When done, get ready to pain platforms (with colliders)
- Firstly, disable Background (make it inactive)
- Create a new tilemap (RMB over Grid-> 2D Object->Tilemap->Rectangular)
- New name the new map to Platforms
- In the TilePlatte: select Platforms as target to work on
- Now, paint the platforms
- Repeat for MovableTiles map
- Collision support:
- Idea: separate collide-able tiles in separate layers of maps. In our case, the Platform map.
- After drawing, can switch on collision for individual maps by adding TilemapCollider2D component: (Add Component->Tilemap->Tilemap Collider 2D)
- Note: all defined tiles in the layer will have Collider2D defined and can detect collision
- For more accurate/smooth collision support: on MovableTiles
- CompositeCollider2D: can add a CompositeCollider2D to the Tilemap’s map to smooth out issues involved with too many colliders
- Here is a short discussion on the issue: https://www.youtube.com/watch?v=Z0O59mWbq1E
- Note:
- A RigidBody2D component will be automatically added to the map, you probably want to change the type to Kinematic.
- The TileMapCollider2D::Used by Composite switch!
- Note:
- Remember: Collider2D size can be adjusted (e.g., to be larger or smaller than the actual object)
- For collision to occur, one of the parties must have RigidBody2D defined (everything learned about collision in Unity applies here). So, if hero wants to walk over the tiles, the Hero should have RigidBody2D (and at least one Collider2D) defined. Recall:
- Dynamic: will be move according to Physics (try setting Gravity Scale to 0)
- Kinematic: only for collision but cannot response (no movement after colliding)
- Player/TileMap Layering: https://www.youtube.com/watch?v=rVBzTKvoStk
- Control: Renderer->Additional Setting: Order in layers
- Layers: 2: HeroKnight, 1: Platform, 0:Background
- Learned: again mostly Unity tools
- TilePlatte: how to create, how to paint on different maps
- Tilemap: separate maps for separate characteristics, including colliders
- Collisions: probably always use Composite Colliders for platformers
- Credits:
5. Particle Systems
o Take
a look at Unity Manual: https://docs.unity3d.com/Manual/ParticleSystems.html
o Focus on Build-in Particle System
o Imaging a collection of points following a pseudo random function