🎉 Add initial T-Rex shader

2022-01-01 19:48:24 +01:00
parent 11a3562533
commit 918a12060c
5 changed files with 146 additions and 0 deletions
@@ -0,0 +1,136 @@
+//////////////////////////////////////////////////////////////////////////////////////////
+//          )                                                   (                       //
+//       ( /(   (  (               )    (       (  (  (         )\ )    (  (            //
+//       )\()) ))\ )(   (         (     )\ )    )\))( )\  (    (()/( (  )\))(  (        //
+//      ((_)\ /((_|()\  )\ )      )\  '(()/(   ((_)()((_) )\ )  ((_)))\((_)()\ )\       //
+//      | |(_|_))( ((_)_(_/(    _((_))  )(_))  _(()((_|_)_(_/(  _| |((_)(()((_|(_)      //
+//      | '_ \ || | '_| ' \))  | '  \()| || |  \ V  V / | ' \)) _` / _ \ V  V (_-<      //
+//      |_.__/\_,_|_| |_||_|   |_|_|_|  \_, |   \_/\_/|_|_||_|\__,_\___/\_/\_//__/      //
+//                                 |__/                                                 //
+//                       Copyright (c) 2021 Simon Schneegans                            //
+//          Released under the GPLv3 or later. See LICENSE file for details.            //
+//////////////////////////////////////////////////////////////////////////////////////////
+
+'use strict';
+
+const {Clutter, GObject, GdkPixbuf, Cogl} = imports.gi;
+
+const ExtensionUtils = imports.misc.extensionUtils;
+const Me             = imports.misc.extensionUtils.getCurrentExtension();
+const shaderSnippets = Me.imports.src.extension.shaderSnippets;
+
+//////////////////////////////////////////////////////////////////////////////////////////
+//////////////////////////////////////////////////////////////////////////////////////////
+
+var TRexShader = GObject.registerClass({Properties: {}, Signals: {}},
+                                       class TRexShader extends Clutter.ShaderEffect {
+  _init(settings) {
+    super._init({shader_type: Clutter.ShaderType.FRAGMENT_SHADER});
+
+    // Load the font texture. As the shader is re-created for each window animation, this
+    // texture is also re-created each time. This could be improved in the future!
+    const clawData    = GdkPixbuf.Pixbuf.new_from_resource('/img/claws.png');
+    this._clawTexture = new Clutter.Image();
+    this._clawTexture.set_data(
+        clawData.get_pixels(), Cogl.PixelFormat.RGB_888, clawData.width, clawData.height,
+        clawData.rowstride);
+
+    // This is partially based on https://www.shadertoy.com/view/ldccW4 (CC-BY-NC-SA).
+    this.set_shader_source(`
+
+      // Inject some common shader snippets.
+      ${shaderSnippets.standardUniforms()}
+      ${shaderSnippets.noise()}
+
+      uniform sampler2D uClawTexture;
+
+      const vec2 SEED = vec2(${Math.random()}, ${Math.random()});
+
+      vec2 getClawUV(vec2 texCoords, float globalScale, vec2 seed) {
+
+        vec2 coords = texCoords + rand2(seed);
+        coords *= uSizeX < uSizeY ? vec2(1.0, 1.0 * uSizeY / uSizeX) : vec2(1.0 * uSizeX / uSizeY, 1.0);
+        
+        coords *= globalScale;
+
+        vec2 uv = mod(coords, vec2(1));
+        vec2 block = coords-uv + vec2(362.456);
+
+        float scale    = mix(0.8, 1.0,         rand(block*seed*134.451));
+        float offsetX  = mix(0.0, 1.0 - scale, rand(block*seed*54.4129));
+        float offsetY  = mix(0.0, 1.0 - scale, rand(block*seed*25.3089));
+        float rotation = mix(0.0, 2.0 * 3.141, rand(block*seed*2.99837));
+        
+        uv -= vec2(offsetX, offsetY);
+        uv /= scale;
+
+        uv -= 0.5;
+        uv = vec2(uv.x * cos(rotation) - uv.y * sin(rotation),
+                  uv.x * sin(rotation) + uv.y * cos(rotation));
+        uv += 0.5;
+
+        return clamp(uv, vec2(0), vec2(1));
+      }
+
+      void main() {
+
+        
+
+        const float CLAW_SIZE       = 1;
+        const float NUM_CLAWS       = 5;
+        const float MAX_SPAWN_TIME  = 0.5;
+        const float FF_TIME         = 0.5;  // Relative time for the final fade to transparency.
+
+        float fade = smoothstep(0, 1, 1 - clamp((uProgress - 1.0 + FF_TIME)/FF_TIME, 0, 1));
+
+        float mask = 1.0;
+
+        vec2 coords = cogl_tex_coord_in[0].st * 2.0 - 1.0;
+        float dist = length(coords);
+
+        coords = (coords/dist * pow(dist, 1.1)) * 0.5 + 0.5;
+
+        coords = mix(cogl_tex_coord_in[0].st, coords, uProgress);
+
+        for (int i=0; i<NUM_CLAWS; ++i) {
+          vec2 uv = getClawUV(coords, 1.0/CLAW_SIZE, SEED*(i+1));
+          float delay = i/NUM_CLAWS * MAX_SPAWN_TIME;
+          mask = min(mask, clamp(texture2D(uClawTexture, uv).r + delay, 0, 1));
+        }
+
+
+
+        // Get the window texture.
+        vec2 dir = vec2(dFdx(mask), dFdy(mask))*uProgress*mask*0.5;
+        cogl_color_out = texture2D(uTexture, coords + dir);
+
+        float flash = 25 * (mask - uProgress) + 1;
+        if (flash < 0 || flash >= 1) {
+          flash = 0;
+        }
+
+        cogl_color_out *= (mask > uProgress ? 1 : 0);
+        cogl_color_out.rgb += flash * mix(vec3(1, 0, 0), vec3(0), uProgress);
+
+        
+
+        cogl_color_out *= fade;
+
+        // cogl_color_out = vec4(vec3(flash), 1);
+        // cogl_color_out = vec4(vec3(mask), 1);
+
+      }
+    `);
+  };
+
+  // This is overridden to bind the claw texture for drawing. Sadly, this seems to be
+  // impossible under GNOME 3.3x as this.get_pipeline() is not available. It was called
+  // get_target() back then but this is not wrapped in GJS.
+  // https://gitlab.gnome.org/GNOME/mutter/-/blob/gnome-3-36/clutter/clutter/clutter-offscreen-effect.c#L598
+  vfunc_paint_target(node, paint_context) {
+    const pipeline = this.get_pipeline();
+    pipeline.set_layer_texture(1, this._clawTexture.get_texture());
+    this.set_uniform_value('uClawTexture', 1);
+    super.vfunc_paint_target(node, paint_context);
+  }
+});