From 6861a93a8257cdf41ef4c035180c98a77849afad Mon Sep 17 00:00:00 2001
From: kainage <kainage@XPS15>
Date: Thu, 17 Sep 2020 21:39:14 -0700
Subject: [PATCH] Allow setting alpha for 2D camera flash effect

* Allow the overriding of `this.alpha` value for the camera flash effect
---
 src/cameras/2d/effects/Flash.js | 19 +++++++++++++++----
 1 file changed, 15 insertions(+), 4 deletions(-)

diff --git a/src/cameras/2d/effects/Flash.js b/src/cameras/2d/effects/Flash.js
index 2d9898901..07caf8f7f 100644
--- a/src/cameras/2d/effects/Flash.js
+++ b/src/cameras/2d/effects/Flash.js
@@ -104,10 +104,9 @@ var Flash = new Class({
          *
          * @name Phaser.Cameras.Scene2D.Effects.Flash#alpha
          * @type {number}
-         * @private
          * @since 3.5.0
          */
-        this.alpha = 0;
+        this.alpha = 1;
 
         /**
          * If this effect is running this holds the current percentage of the progress, a value between 0 and 1.
@@ -128,6 +127,17 @@ var Flash = new Class({
          */
         this._elapsed = 0;
 
+        /**
+         * This is an internal copy of the initial value of `this.alpha`, used to calculate the current alpha value of the fade effect.
+         *
+         * @name Phaser.Cameras.Scene2D.Effects.Flash#_alpha
+         * @type {number}
+         * @private
+         * @readonly
+         * @since 3.50.0
+         */
+        this._alpha;
+
         /**
          * This callback is invoked every frame for the duration of the effect.
          *
@@ -191,8 +201,8 @@ var Flash = new Class({
         this.red = red;
         this.green = green;
         this.blue = blue;
-        this.alpha = 1;
 
+        this._alpha = this.alpha;
         this._elapsed = 0;
 
         this._onUpdate = callback;
@@ -230,7 +240,7 @@ var Flash = new Class({
 
         if (this._elapsed < this.duration)
         {
-            this.alpha = 1 - this.progress;
+            this.alpha = this._alpha * (1 - this.progress);
         }
         else
         {
@@ -304,6 +314,7 @@ var Flash = new Class({
      */
     effectComplete: function ()
     {
+        this._alpha = this.alpha
         this._onUpdate = null;
         this._onUpdateScope = null;