Enhancing The User Experience: GUI and Sound - Learn Unity3D Programming with UnityScript - page 302

In the GUIScript, experiment with changing the (x, y) values to relocate the label. When you also
experiment with the Rect size properties, you will find that when you make the label smaller, the text
is cut off and does not reduce in size along with the rectangle's dimensions.

Fading Out
Suppose at the start of the game you would like to inform the player how to make the player
character crouch and jump with a message that fades away after 3 seconds. Edit the GUIScript to
the following:

#pragma strict

public var fadeDuration : float = 3;

function OnGUI() {
var fadingColor : Color;
fadingColor = GUI.contentColor;
var fading : float = (Time.time/fadeDuration);
GUI.contentColor.a = Mathf.Lerp(1, 0, fading);
GUI.Label(Rect(0, 0, 250, 25), "Press C to crouch or Space to jump");
}

Breaking this down:

(1) public var fadeDuration : float = 3;

Declare a float type variable fadeDuration and assign it a value of 3.

1.

(2) var fadingColor : Color;

Declare a reference variable fadingColor of type Color . Recall that Color
is made up of r, g, b, a values where a, the alpha value, represents the
transparency such that 1 is fully opaque and 0 is fully transparent.

2.

(3) fadingColor = GUI.contentColor;

Assign the current GUI text Color value held by the GUI class contentColor
variable to the fadingColor variable.

3.

(4) var fading : float = (Time.time/fadeDuration);

Declare a float type variable fading to hold the result of the time since game
start divided by fadeDuration in seconds.

4.

(5) GUI.contentColor.a = Mathf.Lerp(1, 0, fading);