Changing Colors

• I'd like to make my text gradually change colors.
• I am modeling this after opening the door.
• The entire thing will be driven by an Event Tick event.
  • This is in the Event graph, so find it.
  • 
• We will use a timeline node
  • When started, this node will create a series of values based on the time offset from the start.
  • It will create an output variable based on a defined curve.
  • We could do several things here, but this is m
• Our first problem is that we don't want the timeline to restart on every tick.
  • We could do several things here, but this is my solution is as follows

  • bool playing = false;
    
    void OnTick() {
        TimeLine myTimeLine;
    
        if (not playing){
            playing = true;
    	myTimeLine.Start()
        }
    }
    
    TimelineUpdate(){
    
        float time;
        float hue;
        vector color
        
        time = myTimeLine.GetTime();
        hue = time(360) + (1-time) * 0
        color = HSVtoRGB(hue,1,1);
        textRender.SetColor(color);
    }
    
    TimeLineFinished() {
        playing = false; 
    }
    
    	  

• The blueprint graph.
  • Declare a bool, initialized to false for playing.
  • 
  • Create a branch based on this bool.
  • 
  • When the color change is false, start the timeline running.
    • I shaped this to go between 0 and 1 in ten seconds.
    • You could probably go between 360 and 0, but that is not what I wanted to do.
    • 
  • LERP - Linear Interpolation
    • This concept is useful everywhere.
    • $ F(\alpha) = \alpha*StartValue + (1-\alpha)* EndValue$
    • A lerp node takes
      • StartValue
      • EndValue
      • $\alpha$
    • 
  • HSVtoRGB
    • HSV is an alternative color space.
    • Wikipedia has a great article
    • Nice smooth transition of colors.
    • 
  • Set the Render Color for the Text Render object.
    • I bet text render color is an attribute of a parent class.
    • So we call that function.
    • 
    • Note that this gets called from the update portion tab of the timeline
    • Note also, the cast from one color type to another was automatically added.
  • Then set the boolean flag to be true.
  • 
  • On last bit, when the timeline is finished, reset the boolean flag to be false, to start the process over again.
  • 
  • The entire process
  • 
• Bonus, I added another timeline and logic to make the word move up and down.
• 
• 
• After some clean up
•