🔧 Use factory to create shaders

src/Apparition.js

@@ -13,25 +13,50 @@
 
 'use strict';
 
-const GObject = imports.gi.GObject;
-
 const _ = imports.gettext.domain('burn-my-windows').gettext;
 
 const ExtensionUtils = imports.misc.extensionUtils;
 const Me             = imports.misc.extensionUtils.getCurrentExtension();
 const utils          = Me.imports.src.utils;
-const Effect         = Me.imports.src.Effect.Effect;
+const ShaderFactory  = Me.imports.src.ShaderFactory.ShaderFactory;
 
 //////////////////////////////////////////////////////////////////////////////////////////
 // This effect hides the actor by violently sucking it into the void of magic.          //
-// towards the middle and then hiding the resulting line from left and right towards    //
-// the center.                                                                          //
 //////////////////////////////////////////////////////////////////////////////////////////
 
 // The effect class can be used to get some metadata (like the effect's name or supported
 // GNOME Shell versions), to initialize the respective page of the settings dialog, as
 // well as to create the actual shader for the effect.
-var Apparition = class Apparition extends Effect {
+var Apparition = class Apparition {
+
+  // The constructor creates a ShaderFactory which will be used by extension.js to create
+  // shader instances for this effect. The shaders will be automagically created using the
+  // GLSL file in resources/shaders/<nick>.glsl. The callback will be called for each
+  // newly created shader instance.
+  constructor() {
+    this.shaderFactory = new ShaderFactory(this.getNick(), (shader) => {
+      // Store uniform locations of newly created shaders.
+      shader._uSeed       = shader.get_uniform_location('uSeed');
+      shader._uShake      = shader.get_uniform_location('uShake');
+      shader._uTwirl      = shader.get_uniform_location('uTwirl');
+      shader._uSuction    = shader.get_uniform_location('uSuction');
+      shader._uRandomness = shader.get_uniform_location('uRandomness');
+
+      // Write all uniform values at the start of each animation.
+      shader.connect('begin-animation', (shader, settings) => {
+        // If we are performing an integration tests, we use a fixed seed.
+        const testMode = settings.get_boolean('test-mode');
+
+        // clang-format off
+        shader.set_uniform_float(shader._uSeed,       2, [testMode ? 0 : Math.random(), testMode ? 0 : Math.random()]);
+        shader.set_uniform_float(shader._uShake,      1, [settings.get_double('apparition-shake-intensity')]);
+        shader.set_uniform_float(shader._uTwirl,      1, [settings.get_double('apparition-twirl-intensity')]);
+        shader.set_uniform_float(shader._uSuction,    1, [settings.get_double('apparition-suction-intensity')]);
+        shader.set_uniform_float(shader._uRandomness, 1, [settings.get_double('apparition-randomness')]);
+        // clang-format on
+      });
+    });
+  }
 
   // ---------------------------------------------------------------------------- metadata
 
@@ -83,51 +108,4 @@ var Apparition = class Apparition extends Effect {
   getActorScale(settings) {
     return {x: 2.0, y: 2.0};
   }
-
-  // This is called by the effect's base class whenever a new shader is required. Since
-  // this shader depends on classes by GNOME Shell, we register it locally in this method
-  // as this file is also included from the preferences dialog where those classes would
-  // not be available.
-  createShader() {
-
-    // Only register the shader class when this method is called for the first time.
-    if (!this._ShaderClass) {
-
-      const Shader = Me.imports.src.Shader.Shader;
-
-      this._ShaderClass = GObject.registerClass({}, class ShaderClass extends Shader {
-        // We use the constructor of the shader to store all required uniform locations.
-        _init(effect) {
-          super._init(effect);
-
-          this._uSeed       = this.get_uniform_location('uSeed');
-          this._uShake      = this.get_uniform_location('uShake');
-          this._uTwirl      = this.get_uniform_location('uTwirl');
-          this._uSuction    = this.get_uniform_location('uSuction');
-          this._uRandomness = this.get_uniform_location('uRandomness');
-        }
-
-        // This is called once each  time the shader is used. This can be used to retrieve
-        // the configuration from the settings and update all uniforms accordingly.
-        beginAnimation(actor, settings, forOpening) {
-          super.beginAnimation(actor, settings, forOpening);
-
-          // If we are currently performing integration test, the animation uses a fixed
-          // seed.
-          const testMode = settings.get_boolean('test-mode');
-
-          // clang-format off
-          this.set_uniform_float(this._uSeed,       2, [testMode ? 0 : Math.random(), testMode ? 0 : Math.random()]);
-          this.set_uniform_float(this._uShake,      1, [settings.get_double('apparition-shake-intensity')]);
-          this.set_uniform_float(this._uTwirl,      1, [settings.get_double('apparition-twirl-intensity')]);
-          this.set_uniform_float(this._uSuction,    1, [settings.get_double('apparition-suction-intensity')]);
-          this.set_uniform_float(this._uRandomness, 1, [settings.get_double('apparition-randomness')]);
-          // clang-format on
-        }
-      });
-    }
-
-    // Finally, return a new instance of the shader class.
-    return new this._ShaderClass(this);
-  }
 }