Week 1:

Intro and learn the tools. Please download and unzip the Week1.zip file in the Files/WeeklyExmaples folder.

• 
  NEED TO DO: explain when we are defining classes, when are the classes instantiated
  • When a GameObject is dragged/created in the Scene (shows in Hierarchy)
  • When a script is dragged into a GameObject that is in the world/Hierarchy
  • When a Prefab is created (in the Resource folder), NO NEW instances are created
    • Only created when we instantiate a new PreFab

Example 1. Intro To Tool: Working with GameObject

• BounceUpAndDown: scripting, the prototype: Start() + Update()
  • On MyCube
  • Public variables are visible on the UI editor (yRange)
    • Warning: If you change this during runtime, the value WILL NOT be saved!
  • Private variables are not visible

• Finding object by name: MyCylinder
  • In general, learn how to formulate what you need and “google” for how to.
  • I do not know how to use Unity or program it (and I am proud of it J).
• Accessing:
  • Transform component: ALWAYS THERE!
  • Renderer and the Material
• Creating and using: PreFab
  • MyCube (in the Assets folder)
• Scene file: ClassExample
  • This is like a “level” in a game
  • Or simply, this is the saved working data
  • Nice thing: you can have multiple versions of “saved data” per work session

• Creating a click-runnable system
  • Take note of what must be included in the execution submission.
  • MP (or machine problem, or programming assignment) submissions:
    • EXE folder: containing something I (and the grader) can double click to test run
    • Src folder: containing the “source system” where we can run the editor and interactive examine your system.

• Name your executables according to FirstLastnameMP#.exe (NO SPACE!)

• Debugging:
  • Unity: Run Game
  • Visual Studio: Attach to Unity (DebugàAttach Unity Debugger)
• Cameras: Notice, there are two
  • Editor camera: this is the camera you use during the edit session. This camera is not visible when the game is running.
    • ALT-LMB to tumble (rotate) this camera in the editor
  • Main Camera: this is the camera that presents the game when you run.
• Lastly, BUT VERY IMPORTANTLY: Potential parent-child relationship of GameObject
  • Find out how to establish parent-child, what is the effect (like grouping)
  • We will learn much much more about this in a couple of weeks

Example 2. SimpleGUI: Creating GUI elements

• Importance of: GameObject --> UI
  • Must create at least one Canvas to contain UI elements!
  • EventSystem: automatically created [NEED THIS!!]
    • Don’t need to change this, but DO NOT delete this.
• Rename Canvas to: MainCanvas
• Learn about Canvas and placement of GUI elements
  • Canvas: UI Canvas - Unity Official Tutorials
  • Rect Transform: Rect Transform - Unity Official Tutorials
• By default, Position specification is a percentage of the entire display
• MainController.cs: Script for the main canvas
  • “using” UnityEngine.UI
  • Note on Prefab instantiation: MyCube must be located in Resources folder
• Create UI elements as children to the MainCanvas! (-->RMB-->UI)
  • UI elements are created in the UI-layer, see how to view/hide layers
  • Notice:
    • working on TWO separate groups of objects: GameObjects and UI
    • Two distinct coordinate systems!!? [More about this later!]
• Structure of source code: anticipating growth
• Resources: resources to be loaded at run time
• Source: source code system, folder structure for future growth: Prefab, UI [there will be more, much more!]
• BUT, how to mouse-click to select? Before we learn about mouse-clicking, let's reaffirm variables and Unity component references ... 

Example 3. Components and Variables: 

• Two scripts:
  • MoveInX: behavior is simple
    • Bounces in X
    • Allow changing of bouncing speed (Inc/Dec Delta)
  • MainControl:
    • Two references to components
      • An object: the moving cube (Object)
      • A script: the moving component on the cube
    • Three buttons:
      • DeleteMoveInX: delete the moving script (component)
      • CreateCube + MoveInX: creates a MoveInX for the cube (what happens when a cube has two MoveInX?
      • DeleteCube: deletes the cube
  • Run the game: Observe the Cube, its speed alternates (controlled by MainControl). Try the following: 
    • Select the CubeHasMoveComponent from the Hierarchy and examine its components in the Inspector
    • Click on DeleteCube'sMove, what happened?
    • Click on CreateCuve + MoveInX, what happens? What happens when you click on this multiple times?
    • Click on DeleteCube, and click on CreateCube again, what happens now? (A new Cube is created)
  • First point to note: "C# Scripts" (MonoBehavior objects) are "components", just like GameObject
    • Notice: how these things are Destroy() [same function call to remove them]
  • Second point to note: components can be referenced by variables  and create/delete dynamically at run time.
    • Notice: both GameObject and "C# Scripts" can be created and deleted during run time.
    • The action of "draggin" a script onto a GameObject to associate the defined behavior with the object, actually:
      • Create a new instance of the script object (e.g., MoveInX)
      • Create a reference from the GameObject to the new script (e.g., the MoveInX object.)
      • This is exactly the same as calling GameObject.AddComponent<DataType>() [called in MainControl::CreateComponent()]. 

Example 4. MouseClickSelect: support mouse clicks

• MaiinController_MouseSupport.cs (Source/UI_Support)
• Notice C# Keyword: partial (separate source code files for the same class)
• MainController::DeleteSelectedCube();
  • Implementation is simple!
• MainController::Update()
  • Must call LMBSelect()!!
    
    

Example 5. GroupingUI: grouping related GUI objects together

• ObjectControlPanel UI element (in Hierarchy window: inside MainCanvas)
  • Always (for us): 
    • Top-level is a Panel (so that the group can be instantiated in the MainCanvas)
    • Note: the Rect Transform: reference placement (try changing the game window size and see ObjectControl is defined with respect to the lower-right corner).
  • GUI elements:
    • GroupLabel: a Text
    • Delete: A button
    • SizeControl: A slider + text (Size Control)

• Behavior: is on the top-leevel Panel (the Script object defined in Source/Prefab Support/ UIPrefab)
• NOTE:
  • RectTransform: is a specialization [subclass] of Transform
  • Button: is a GameObject with Scripts! Button is a script!
    • call GetComponent() to access the actual button!
  • New ObjectControlPanel prefeb
    • Resources/UI/ObjectControl
    • Source/Prefab Support/UIPrefab: the script

• To create: drag ObjectControlPanel prefeb into the world

• MainController.cs
  • No need to have any support for working with selected object
  • Much cleaner!! Easier to maintain!
• Problem:
  • Click to select any object, drag size control slider to make the object small
  • Now, click to select another object in the scene
  • Note: the newly selected object size is changed to the current size control value!
  • Problem: UI/Object two-way binding is not properly supported