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Unity Coroutines vs C# Async. Programming. Cameras. General. Viewport Rect (Split-Screen Setup). Creating a Layered GUI Camera
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Unity Coroutines vs C# Async
● Async:
○ Best Practices for Async vs Coroutines: Best practices: Async vs. coroutines - Unite Copenhagen
○ Best for handling User Interaction, Network Calls
● Coroutines:
○ Unity - IEnumerator's yield return null
■ The top answer by user “Everts” gives a very good explanation of what a Coroutine is
○ Does not support Return values
○ Best for “Fire and forget” scenarios;
■ Closing a Window
■ Animating a background detail
○ Coroutine Method: A coroutine must be declared as an “IEnumerator”
IEnumerator MethodName() {
SomeFunction();
yield return null;
AnotherFunction();
}
○ Yield return null: This will cause the method to wait for a single frame before executing AnotherFunction();
● Yield return WaitForSeconds:
Unity - Scripting API: WaitForSeconds
○ If you intend to wait more than a single frame using “yield return null” you can use WaitForSeconds instead.
● Garbage Collection Tip:
C# Coroutine WaitForSeconds Garbage Collection tip
○ The typical way of using “Yield return WaitForSeconds” involves creating a “new” WaitForSeconds in the return line as seen below;
yield return new WaitForSeconds (letterDelay);
○ The full example below results in less Garbage Collection Allocation; by declaring a “shortWait” and returning that in the Coroutine instead
● Coroutine Example Use Snippet: The following snippet creates a series of GameObjects based on a prefab, and assigns each a sprite based on the Sprites List
public GameObject letterPrefab;
public List< Sprite> letters = new List< Sprite> ();
public float letterDelay = 0. 05f;
WaitForSeconds shortWait = new WaitForSeconds(letterDelay);
void Start() {
StartCoroutine(SpawnLetters());
}
IEnumerator SpawnLetters() {
foreach (var letter in letters) {
GameObject newLetter = Instantiate(letterPrefab, transform, false);
newLetter. GetComponent< Image> (). sprite = letter;
yield return shortWait;
}
}
● Coroutine Task Manager:
○ https: //forum. unity. com/threads/a-more-flexible-coroutine-interface. 94220/? _ga=2. 153570993. 846436558. 1592243927-174792342. 1591205497
● Using Async:
Programming
● Check Implementation: To see if a class inherits from a given class, you can use a cast or GetComponent:
IinterfaceName interface = gameObject. GetComponent< IinterfaceName> ();
if (interface! = null)
interface. MethodSignatureName(argumentsHere);
● Convert Degree into Vector2; Convert a Float into a x / y Vector2
Vector2 dir = (Vector2)(Quaternion. Euler(0, 0, degree) * Vector2. right);
○ Other helper Functions; Equivalent of " Degree to Vector2" in Unity
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Cameras
General
● Reference: https: //docs. unity3d. com/Manual/class-Camera. html
● Clear Flags: What the Camera is “cleared with” each frame
○ Skybox: By default, the camera is cleared with the “Skybox”
○ Solid Color: A flat color, preferable for 2D games
○ Depth Only: All information about where an object exists in 3D space is discarded (in a first person shooter, if you have your weapon aimed at a wall and it’s barrel would be clipping into the Wall, this setting would allow the weapon to be drawn without regard to the wall geometry)
○ Don’t Clear: You will handle the responsibility of clearing the camera
● Culling Mask: Which Layers the Camera can see.
○ By default, each Camera can see “Everything”
● Depth: If multiple Cameras exist in the Scene, they are rendered from lowest Depth to highest
○ If 2 Cameras are in the Scene;
■ Camera A with a Depth of 10
■ Camera B with a Depth of -10
■ Camera A will be drawn to the scene, then Camera B will be drawn over top of it.
○ To ensure multiple overlapping Camera views are visible, use the Culling Mask and Clear Flags features.
● No need for multiple Audio Listeners: Each Camera will, by default have an Audio Listener Component added to it which should be removed.
Viewport Rect (Split-Screen Setup)
● Reference: Split Screen in Unity - YouTube
● Viewport Rect: Controls the X / Y position of the camera’s view within the overall viewport of the game
○ X / Y: Anchored from the bottom-left, sets the viewport position from (0-1)
○ W / H: As a percentage, sets how much of the width / height the viewport takes up (0-1)
● Split Screen Setup:
○ Top / Bottom: Set the [W/H] to [1, 0. 5] for both Cameras (so that they each only occupy half the height of the overall view)
■ Set the Viewport of Camera A to; [X/Y] [0, 0. 5] to push it half-way up the view
■ Leave the Viewport of Camera B to; [X/Y] [0, 0]
Creating a Layered GUI Camera
● If you need an Orthographic Camera to render 3D objects on a GUI layer while a regular Perspective Camera renders the rest of the Scene;
● Reference: Camera Layering in Unity - YouTube
● Perspective Camera Setup:
○ Culling Mask: Untick the “UI” Layer (and any other Layers this camera should not see)
● GUI Camera Setup:
○ Clear Flags: Depth Only
○ Culling Mask: Set to Nothing but “UI” (and any other layers this should see)
○ Projection: Orthographic
○ Depth: 10 (any Depth above the Perspective Camera to ensure it renders above it)
○ Remove Audio Listener Component: If there is a 2nd one which you don’t want
● Canvas Setup:
○ Set Layer: To “UI”
○ Render Mode: Screen Space - Camera
○ Render Camera: Specify reference to GUI Camera
○ Optional; set the GUI Camera as a Child of the Canvas
■ This way, if the Canvas is disabled, so is the GUI Camera
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