How to flash screen color in Unity 5

Questions & Answers
1

The standard answer for this seems to make a screen sized GUITexture and manipulate its Alpha.

Untiy 5 however has removed GUITexture from the object menu and marked it “legacy”.

This is what I tried, but it didn’t seem to work:
(1) Add a GUITexture component to my RigidBody FPS controller.
(2) Add a GUITextureLayer to my Rb FPS controller’s camera

Is this still the preferred method for flashing the entire screen to a given color? If so what else do I need to do to see the GUITexture?

3

If you have a Pro license(or using the 30day free trial) you have access to image post processing effects.

Otherwise you could use a cheap trick maybe by making a plane the child of the camera facing it and assign a material. Another thing is you can use the OnGUI to draw a rect on the screen and flash it.

4

I ended up solving it using GUI.DrawTexture. Code below.

using UnityEngine;
using System.Collections;

public class DamagedFlash : MonoBehaviour {
	private Texture2D pixel;
	public Color color = Color.red;
	public float startAlpha=0.0f;
	public float maxAlpha=1.0f;
	public float rampUpTime=0.5f;
	public float holdTime=0.5f;
	public float rampDownTime=0.5f;

	enum FLASHSTATE {OFF,UP,HOLD,DOWN}
	Timer timer;
	FLASHSTATE state = FLASHSTATE.OFF;

    
	// Use this for initialization
	void Start(){
		pixel = new Texture2D(1,1);
		color.a = startAlpha;
		pixel.SetPixel(0,0,color);
		pixel.Apply();
		// for testing
		//TookDamage(new DamagePacket(1));
	}

	public void Update() {
		switch(state){
			case FLASHSTATE.UP:
			    if (timer.UpdateAndTest()){
					state =FLASHSTATE.HOLD;
					timer = new Timer(holdTime);
				}
				break;
		    case FLASHSTATE.HOLD:
				if (timer.UpdateAndTest()){
					state =FLASHSTATE.DOWN;
					timer = new Timer(rampDownTime);
				}
			break;
			case FLASHSTATE.DOWN:
				if (timer.UpdateAndTest()){
					state =FLASHSTATE.OFF;
					timer = null;
				}
			break;
		}
	}

	private void SetPixelAlpha(float a){
		color.a = a;
		pixel.SetPixel(0,0,color);
		pixel.Apply();
	}

	public void OnGUI(){
		switch(state){
			case FLASHSTATE.UP:
				SetPixelAlpha(Mathf.Lerp(startAlpha,maxAlpha,timer.Elapsed));
				break;
			case FLASHSTATE.DOWN:
				SetPixelAlpha(Mathf.Lerp(maxAlpha,startAlpha,timer.Elapsed));
				break;
		}
		GUI.DrawTexture(new Rect(0,0,Screen.width, Screen.height), pixel);
	}

	public void TookDamage(DamagePacket dmg){
		timer = new Timer(rampUpTime);
		state = FLASHSTATE.UP;
	}

}

The Timer class is a utility that looks like that.

using UnityEngine;
using System.Collections;

/***
 * This class provides an in game loop timer mechanism
 ***/

public class Timer  {
	float _timeElapsed;
	float _totalTime;

	public Timer(float timeToCountInSec){
		_totalTime = timeToCountInSec;
	}

	public bool UpdateAndTest(){
		_timeElapsed+= Time.deltaTime;
		return _timeElapsed>=_totalTime;
	}

	public float Elapsed{
		get {return Mathf.Clamp(_timeElapsed/_totalTime,0,1);}
	}
}
2

If you create an empty GameObject you can go Add Component > Rendering > GUI Texture.