How to make a FLASH

Questions & Answers
1

I was trying to make a video camera in a test project and it’s almost done. I have the camera prefab, i have the viewer, i have the “take a photo” script, but i need a last thing, and i don’t know how to make it.

Most cameras make a white flash when they take a photo. How can i do this in a game? Like, how do i create a flash particle or something and apply it to the game? Like a shot, but a flash instead.

4

  1. Create a c# script named Flash, copy & paste this script into it.

  2. Create a white UI Image (GameObject->UI->Image), pick a Source Image for the image in the inspector (I used a 4x4 white pixel). Set the RecTransform to stretch, 0, 0, 0, 0 (left/top/right/bottom).

  3. Attach the Flash script to your UI Image object.

This was quick and dirty, but I think it works well.

using UnityEngine;
using UnityEngine.UI;
using System.Collections;

public class Flash : MonoBehaviour {
	///////////////////////////////////////////////////
	public float flashTimelength = .2f;
	public bool doCameraFlash = false;

	///////////////////////////////////////////////////
	private Image flashImage;
	private float startTime;
	private bool flashing = false;

	///////////////////////////////////////////////////
void Start()
{
	flashImage = GetComponent<Image>();
	Color col = flashImage.color;
	col.a = 0.0f;
	flashImage.color = col;
}

	///////////////////////////////////////////////////
	void Update () {
		if(doCameraFlash && !flashing)
		{
			CameraFlash();
		}
		else
		{
			doCameraFlash = false;
		}
	}

	///////////////////////////////////////////////////
	public void CameraFlash()
	{
		// initial color
		Color col = flashImage.color;

		// start time to fade over time
		startTime = Time.time;

		// so we can flash again
		doCameraFlash = false;

		// start it as alpha = 1.0 (opaque)
		col.a = 1.0f;

		// flash image start color
		flashImage.color = col;

		// flag we are flashing so user can't do 2 of them
		flashing = true;

		StartCoroutine(FlashCoroutine());
	}

	///////////////////////////////////////////////////
	IEnumerator FlashCoroutine()
	{
		bool done = false;

		while(!done)
		{
			float perc;
			Color col = flashImage.color;

			perc = Time.time - startTime;
			perc = perc / flashTimelength;

			if(perc > 1.0f)
			{
				perc = 1.0f;
				done = true;
			}

			col.a = Mathf.Lerp(1.0f, 0.0f, perc);
			flashImage.color = col;
			flashing = true;

			yield return null;
		}

		flashing = false;

		yield break;
	}
}

After that, call CameraFlash() to flash the image. You can test in editor by pressing the “Do Camera Flash” checkbox.

2

It’s a relatively simple script actually, this is some code almost identical to code in the Survival Shooter tutorial:

public Image flashImage;
public float flashSpeed = 5f;
//Time the flash lasts for
public Color flashColour = new Color(1f, 1f, 1f, 1f);
// The values above correspond to: R - G - B - Alpha these values would produce an opaque white flash.

 void Update ()
        {
            if(picture)
            {
                pictureImage.color = flashColour;
            }
            else
            {
                pictureImage.color = Color.Lerp (pictureImage.color, Color.clear, flashSpeed * Time.deltaTime);
            }
            picture = false;

You will then simply need to assign the script and add a ‘flash image’ in the inspector view. Let me know if you need any more help or if i’m generally confusing!

3

If I understand you correctly, you want a white flash to appear when you take a picture? The code would look something like this:

public Color flashColour = new Color(1f, 0f, 0f, 0.1f);
//The values above are in the order of R - G - B - Alpha
public float flashSpeed = 5f;
//The time the flash will last for

void Update ()
    {
        if(take.picture)
        {
            flashImage.color = flashColour;
        }
        else
        {
            flashImage.color = Color.Lerp (flashImage.color, Color.clear, flashSpeed * Time.deltaTime);
        }
        flash = false;

I think that should work, please let me know if it doesn’t!
You’ll also need to assign a few things in the inspector (flash image)

5

Hi,

If the flash is only going to affect the player, you can add a canvas with a white image. Then quickly reduce the alpha of the image and after a few seconds destroy or disable the canvas.