Initial

resources/app/client/pixi/webgl/shaders/weather/fog.js

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+/**
+ * Fog shader effect.
+ */
+class FogShader extends AbstractWeatherShader {
+
+  /** @inheritdoc */
+  static defaultUniforms = {
+    intensity: 1,
+    rotation: 0,
+    slope: 0.25
+  };
+
+  /* ---------------------------------------- */
+
+  /**
+   * Configure the number of octaves into the shaders.
+   * @param {number} mode
+   * @returns {string}
+   */
+  static OCTAVES(mode) {
+    return `${mode + 2}`;
+  }
+
+  /* -------------------------------------------- */
+
+  /**
+   * Configure the fog complexity according to mode (performance).
+   * @param {number} mode
+   * @returns {string}
+   */
+  static FOG(mode) {
+    if ( mode === 0 ) {
+      return `vec2 mv = vec2(fbm(uv * 4.5 + time * 0.115)) * (1.0 + r * 0.25);
+        mist += fbm(uv * 4.5 + mv - time * 0.0275) * (1.0 + r * 0.25);`;
+    }
+    return `for ( int i=0; i<2; i++ ) {
+        vec2 mv = vec2(fbm(uv * 4.5 + time * 0.115 + vec2(float(i) * 250.0))) * (0.50 + r * 0.25);
+        mist += fbm(uv * 4.5 + mv - time * 0.0275) * (0.50 + r * 0.25);
+    }`;
+  }
+
+  /* -------------------------------------------- */
+
+  /** @override */
+  static createProgram() {
+    const mode = canvas?.performance.mode ?? 2;
+    return PIXI.Program.from(this.vertexShader, this.fragmentShader(mode));
+  }
+
+  /* -------------------------------------------- */
+
+  /** @inheritdoc */
+  static fragmentShader(mode) {
+    return `
+    ${this.FRAGMENT_HEADER}
+    uniform float intensity;
+    uniform float slope;
+    uniform float rotation;
+    
+    ${this.CONSTANTS}
+    ${this.PERCEIVED_BRIGHTNESS}
+    ${this.PRNG}
+    ${this.ROTATION}
+     
+    // ********************************************************* //
+
+    float fnoise(in vec2 coords) {
+      vec2 i = floor(coords);
+      vec2 f = fract(coords);
+    
+      float a = random(i);
+      float b = random(i + vec2(1.0, 0.0));
+      float c = random(i + vec2(0.0, 1.0));
+      float d = random(i + vec2(1.0, 1.0));
+      vec2 cb = f * f * (3.0 - 2.0 * f);
+    
+      return mix(a, b, cb.x) + (c - a) * cb.y * (1.0 - cb.x) + (d - b) * cb.x * cb.y;
+    }
+     
+    // ********************************************************* //
+
+    float fbm(in vec2 uv) {
+      float r = 0.0;
+      float scale = 1.0;  
+      uv += time * 0.03;
+      uv *= 2.0;
+        
+      for (int i = 0; i < ${this.OCTAVES(mode)}; i++) {
+        r += fnoise(uv + time * 0.03) * scale;
+        uv *= 3.0;
+        scale *= 0.3;
+      }
+      return r;
+    }
+    
+    // ********************************************************* //
+    
+    vec3 mist(in vec2 uv, in float r) {
+      float mist = 0.0;
+      ${this.FOG(mode)}
+      return vec3(0.9, 0.85, 1.0) * mist;
+    }
+    
+    // ********************************************************* //
+    
+    void main() {
+      ${this.COMPUTE_MASK}
+      
+      vec2 ruv;
+      if ( rotation != 0.0 ) {
+        ruv = vUvs - 0.5;
+        ruv *= rot(rotation);
+        ruv += 0.5;
+      }
+      else {
+        ruv = vUvs;
+      }
+      
+      vec3 col = mist(ruv * 2.0 - 1.0, 0.0) * 1.33;
+      float pb = perceivedBrightness(col);
+      pb = smoothstep(slope * 0.5, slope + 0.001, pb);
+      
+      gl_FragColor = vec4( mix(vec3(0.05, 0.05, 0.08), col * clamp(slope, 1.0, 2.0), pb), 1.0) 
+                     * vec4(tint, 1.0) * intensity * mask * alpha;
+    }
+    `;
+  }
+}
+