♻️ Add base classes for the effects and shaders

src/Shader.js

@@ -0,0 +1,104 @@
+//////////////////////////////////////////////////////////////////////////////////////////
+//          )                                                   (                       //
+//       ( /(   (  (               )    (       (  (  (         )\ )    (  (            //
+//       )\()) ))\ )(   (         (     )\ )    )\))( )\  (    (()/( (  )\))(  (        //
+//      ((_)\ /((_|()\  )\ )      )\  '(()/(   ((_)()((_) )\ )  ((_)))\((_)()\ )\       //
+//      | |(_|_))( ((_)_(_/(    _((_))  )(_))  _(()((_|_)_(_/(  _| |((_)(()((_|(_)      //
+//      | '_ \ || | '_| ' \))  | '  \()| || |  \ V  V / | ' \)) _` / _ \ V  V (_-<      //
+//      |_.__/\_,_|_| |_||_|   |_|_|_|  \_, |   \_/\_/|_|_||_|\__,_\___/\_/\_//__/      //
+//                                 |__/                                                 //
+//                       Copyright (c) 2021 Simon Schneegans                            //
+//          Released under the GPLv3 or later. See LICENSE file for details.            //
+//////////////////////////////////////////////////////////////////////////////////////////
+
+'use strict';
+
+const {Gio, Shell, GObject} = imports.gi;
+const ByteArray             = imports.byteArray;
+
+const ExtensionUtils = imports.misc.extensionUtils;
+const Me             = imports.misc.extensionUtils.getCurrentExtension();
+const utils          = Me.imports.src.utils;
+
+//////////////////////////////////////////////////////////////////////////////////////////
+// This is the base class for all shaders of Burn-My-Windows. It automagically loads    //
+// the shader's source code from the resource file resources/shaders/<nick>.glsl and    //
+// ensures that some standard uniforms are always updated.                              //
+//////////////////////////////////////////////////////////////////////////////////////////
+
+var Shader = GObject.registerClass({}, class Shader extends Shell.GLSLEffect {
+  // The constructor is used to store all required uniform locations. Make sure to chain
+  // up to this base constructor before trying to access the uniform locations!
+  _init(effect) {
+    this._effect = effect;
+
+    // This will call vfunc_build_pipeline().
+    super._init();
+
+    this._uForOpening = this.get_uniform_location('uForOpening');
+    this._uProgress   = this.get_uniform_location('uProgress');
+    this._uTime       = this.get_uniform_location('uTime');
+    this._uSize       = this.get_uniform_location('uSize');
+  }
+
+  // This is called 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) {
+    this.set_uniform_float(this._uForOpening, 1, [forOpening]);
+    this.set_uniform_float(this._uSize, 2, [actor.width, actor.height]);
+  }
+
+  // This is called at each frame during the animation. This can be used to update
+  // uniforms which need to change each frame.
+  updateAnimation(progress, time) {
+    this.set_uniform_float(this._uProgress, 1, [progress]);
+    this.set_uniform_float(this._uTime, 1, [time]);
+  }
+
+  // This is called by extension.js when the shader is not used anymore. We will
+  // store this instance of the shader so that it can be re-used in th future.
+  endAnimation() {
+    this._effect.freeShader(this);
+  }
+
+  // This is called by the constructor. This means, it's only called when the
+  // effect is used for the first time.
+  vfunc_build_pipeline() {
+    const code = this._loadGLSLResource(`/shaders/${this._effect.getNick()}.glsl`);
+
+    // Match anything between the curly brackets of "void main() {...}".
+    const regex = RegExp('void main *\\(\\) *\\{([\\S\\s]+)\\}');
+    const match = regex.exec(code);
+
+    const declarations = code.substr(0, match.index);
+    const main         = match[1];
+
+    this.add_glsl_snippet(Shell.SnippetHook.FRAGMENT, declarations, main, true);
+  }
+
+  // ----------------------------------------------------------------------- private stuff
+
+  // This loads the file at 'path' contained in the extension's resources to a JavaScript
+  // string.
+  _loadStringResource(path) {
+    const data = Gio.resources_lookup_data(path, 0);
+    return ByteArray.toString(ByteArray.fromGBytes(data));
+  }
+
+  // This loads a GLSL file from the extension's resources to a JavaScript string. Any
+  // #include statements in this file are replaced with the corresponding file contents.
+  _loadGLSLResource(path) {
+    let code = this._loadStringResource(path);
+
+    // This regex matches either #include "..." or #include <...>. The part between the
+    // brackets is captured in the capture group.
+    const regex = RegExp('#include ["<](.+)[">]', 'g');
+
+    code = code.replace(regex, (m, file) => {
+      return this._loadStringResource('/shaders/' + file);
+    });
+
+    // Add a trailing newline. Else the GLSL compiler complains...
+    return code + '\n';
+  }
+});