diff --git a/filters/alpha/src/AlphaFilter.js b/filters/alpha/src/AlphaFilter.js
index 13e43aa..90a5bf8 100644
--- a/filters/alpha/src/AlphaFilter.js
+++ b/filters/alpha/src/AlphaFilter.js
@@ -22,13 +22,13 @@
 export default class AlphaFilter extends Filter
 {
     /**
-     *
+     * @param {number} [alpha=1] Amount of alpha from 0 to 1, where 0 is transparent
      */
-    constructor()
+    constructor(alpha = 1.0)
     {
         super(defaultVertex, fragment);
 
-        this.alpha = 1.0;
+        this.alpha = alpha;
         this.glShaderKey = 'alpha';
     }