UNITY: Roll-A-Ball Tutorial

Official Roll-A-Ball Tutorial by Unity3D

http://www.youtube.com/watch?v=lv0SqtSzBxc

Tutorial 01: Setting Up the Game

• Unity primitives are all either 1x1x1 or 1x2x1 in size when created
• Empty Game Objects are used as directories in the Hierarchy

Tutorial 02: Moving the Player

• Rigidbody
• required for physics interaction
• can be created and added directly via "Add Component" in the inspector.
• void Update();
• used for controller inputs, etc.
• void FixedUpdate();
• used for anything physics related
• CTRL + ' when highlighting an object in MonoDevelop will bring up the reference page
• Store "Input.GetAxis" calls in a float variable
• use "rigidbody.Addforce" for physics based movement
• create new Vector3 type variable to store movement
• " Vector3 movement = new Vector3(x, y, z); "
• " rigidbody.AddForce (movement); "
• use " Time.DeltaTime " as frames per second

Tutorial 03: Moving the Camera

• Tying the camera to the Player game object
• not as simple as parenting the camera to the Player object
• add a new script to the Camera object via Add Component
• scripts always get added to the root assets directory, so move it to " scripts "
• create a " GameObject " type public variable called "player" so a field will open up for drag and drop inside of Unity.
• create a Vector3 type private variable called "offset" that the script can alter under the Start() function.
• void LateUpdate();
• follow cameras, procedural animations, gathering last known states
• create reference to player GameObject by dragging in to previously created "player" slot

Tutorial 04: Play Area and Pickup Objects

• Creating environment
• create empty game object as a holder / folder
• reset position back to origin
• create geometry and put it under empty game object for organization
• Creating Pickup items
• create new cube
• lift it, shrink it, and rotate 45 degrees on all axis
• add component: script (for rotating animation)
• not using forces, so we can use " void Update() "
• use lower case "t", " transform.Rotate(new Vector3(15, 30, 45) * Time.DeltaTime); "
• make into Prefab:
• Create "Prefab" Folder
• Drag "Pickup" item from Hierarchy into Prefab folder
• When this is done, a Prefab Item is created
• Item in Hierarchy now shows BLUE
• Create empty GameObject named "Pickups" to hold our pickups in the Hierarchy view
• Reset position to 0,0,0
• Spread Pickup items around
• make sure the blue prefab item itself is selected for duplication, not the group node
• change move to "Global" instead of "Local" 

Tutorial 05: Collecting and Counting

• In order to count items, we have to create collision detections
• collisions have to be detected to trigger new behaviors
• collisions have to be "tested" to see which object has been pinged

• edit "PlayerController" script
• but before that, let's inspect the player object
• We're interested in the "Sphere Collider"
• In object header:
• turn down arrow (reveals more info)
• icon
• enable/disable checkbox
• types of component
• object sensitive gear gizmo
• icon of little book with question mark (help)
• Use book icon to go to offline Reference
• Offline Reference (PC)
• Component Help
• Switch to Scripting Help
• we want to use "OnTriggerEnter" function
• can be used for detecting object collision, without actual physical collision occuring
• "void OnTriggerEnter(Collider other)"
• references the "other" item we collide with
• "Destroy(other.gameObject);" 
• destroys referenced game object that we collided with
• destroyed game objects and all their children are removed from the scene
• In this tutorial, we'll deactivate gameObject instead of destroying it
• Remove the "Destroy" code
• look up "Tag" under "GameObject"
• Tags can be assigned to objects for identification
• Tags must be declared in the "Tag Manager" before using
• look up "SetActive"
• method used to activate or disable objects
• example code:
• if(other.gameObject.tag == "Pickup")
• {
• other.gameObject.SetActive(false);
• }
• Basically checks if other object collided with has a Tag called "Pickup, and if it does, executes the code. In this instance, it tells the other game object to execute "SetActive" method to false.
• In UNITY, select Pickup object and under the inspector, check the TAG list
• add TAG
• under the first element (0), add "Pickup"
• name has to match exactly to the script
• apply tag to prefab
• Turn colliders into "Triggers"
• static objects don't get recalculated
• dynamic objects get recalculated
• must add RigidBody objects
• turn off Use Gravity
• activate "Is Kinematic"
• performane Tidbit:
• UNITY calculates all Static items and holds it in memory cache
• if we rotate a static collider, the cache gets rebuilt globally
• adding RigidBody and turning on "Is Kinematic" excludes items from Static collider cache
• "Is Kinematic" allows for animation through transforms (IE: elevators and moving platforms)

Tutorial 06: Displaying Text

• We need a tool to store collection count, and tool to add on top
• Add these tools to "PlayerController" script
• add private variable "count"
• initialize to zero under Start();
• count = 0;
• under "void OnTriggerEnter(Collider other)"
• add: " count = count + 1 "
• Displaying Info via GUI Text:
• Add new empty GameObject: " Display_Text", transform 0,0,0
• Create "GUI Text" gameObject
• Parent to "Display_Text" game object
• Move to " Upper Left "
• 0,0 = lower left
• 1,1 = upper right\
• Set Transform to 0,1,0
• Then use "Pixel Offset" setting in the GUIText
• X = 10, Y = -10
• Under "PlayerController" script:
• add new public "GUIText" variable called "countText"
• this opens up another slot in Unity that allows for drag and drop
• initialize "countText" to: 
• "Count: " + count.ToString(); 
• count.ToString(); must be after "count" has an initialized value
• update "countText" everytime an object is picked up
• under "void OnTriggerEnter(Collider other)"
• add "countText.text = "Count: " + count.ToString();
• create new function instead of typing "countText.text = ....." repeatedly
• void SetCountText()
• {
• countText.text = "Count: " + count.ToString();
• }
• add function call to respective locations of the script
• drag GuiText object into new "PlayerController" script slot
• VOILA!
• Displaying WIN condition:
• create new GUIText object "WinText"
• parent to DisplayText game object
• add reference to PlayerController script:
• create new public GUIText variable: " winText "
• initialize winText.text = ""; // empty text
• under " SetCountText()" function:
• add:
• if (count >= 12)
• {
• winText.text = "YOU WIN!";
• }
• save and return to unity
• drag-associate WinText object to the PlayerSphere reference call (drop it into the field)

Tutorial 07: Publishing the Game

• Unity can build to all to all target platforms
• Open Build Settings
• Current build settings are denoted by the UNITY icon
• Switch build platform by highlighting target platform, and hitting "Switch Platform"
• Add current scene to build by clicking "Add Current", or drag and drop any scenes from Project folder to the "Scenes to Build" field
• include only the scenes needed
• Hit "Build" button
• Create new folder under main project root folder called "Builds"
• Name the build, and Save