[Editted 8/12 to replace PanelGroup or panel with the correct CanvasGroup or canvas. Hopefully it makes more sense now.]
When I looked for how to adjust the alpha I came across a CanvasGroup component for the Canvas which seems to do exactly what we require without having to create a kind of black curtain across the front of everything.
Basically changing the alpha of a CanvasGroup component appears to affect the alpha for the entire canvas, allowing the whole thing to be simply faded in. Is this a new component with Unity 5, and so not in this course? Or is it a component which is designed for something totally different and it’s purely a fluke it happens to do what I wanted on my screens?
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Do you mean the Canvas Group component?
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Sorry, total brain glitch! Yes, throughout my question read ‘Canvas’ for ‘Panel’.
(In all those emojis I can’t see a single “Oops, I’m a dimbat” one - take it as implicit)
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No problem, I just wanted to be sure, since I didn’t yet know the existence of such component before reading your first post. 
And you’re right, I added it directly on the Canvas object of the main menu, and it worked better than having an additional child panel, which btw “blocked” the buttons before the fade-in was over, with the Canvas Group you can use those buttons even during the fade-in animation.
No need for an animator and a clip, active buttons, simpler fade-in script. Nice catch!
Oh, I checked on my Unity 4, and the component was already there, so it’s not new in Unity 5.
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Original query corrected. Thanks, Galandil, for your reply and comments. 
I was just about to post about my use of adding a Canvas Group to the panel and unchecking “blocks raycast” and “Interactive”. This keeps the buttons interactive during the fade. Seems I just didn’t take the whole Canvas Group thing far enough. Going to head back into my code to replace the panel with a Canvas Group. Nice tip, thanks!
This is amazing! I’ve tried all 3 solutions:
- The one in the lecture
- The CrossFadeAlpha method
- This “Canvas Group” method
The Canvas Group method is the best because:
- It’s most intuitive to set up
- It requires the simplest code
- It allows the user to click around as it fades (the user doesn’t have to wait for the fade to finish in order to click)
For anyone wondering how to replicate:
-
In Unity, in the 01a Start scene, click on Canvas
-
Click Add Component, then add the “Canvas Group” component
-
Set alpha to 0
-
Add Component, make a script, code below (don’t forget to add in the UnityEngine.UI too):
public float fadeInDelay;
private CanvasGroup canvasGroup;
void Start()
{
canvasGroup = GetComponent<CanvasGroup>();
}
void Update()
{
canvasGroup.alpha += Time.deltaTime / fadeInDelay;
}
Hope that helps and thanks again @BlackPhi for finding this!
-Blaine
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