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

· 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

1. 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
  
  
  
2. 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 components)
• 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
  
  
  
3. 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

4. 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