Make clouds2d.js theme-agnostic

- Remove all hardcoded fallback hex/rgb values
- Skip draw until __currentPalette is published by parent
- applyWeatherTheme now also mixes cloudShadow (was dropped)

vendor/clouds2d.js

@@ -4,7 +4,8 @@
  * fragment shader to produce animated cloud-like patterns.
  *
  * Drop-in replacement for Vanta when CONFIG.renderer === 'clouds2d'.
- * Creates its own <canvas> overlay and attaches to the target element.
+ * Reads day/night palette + weather theme from window globals set
+ * by the parent (background.html's animate() loop).
  */
 
 (function() {
@@ -42,14 +43,21 @@ var VERT_SRC = [
     'void main() { gl_Position = vec4(aPos, 0.0, 1.0); }'
 ].join('\n');
 
+// Fragment shader: animates an fBm cloud field, modulates density
+// by weather, blends day/night palette colours, and adds a soft
+// horizon gradient so the sky transitions naturally.
 var FRAG_SRC = [
     'precision highp float;',
     'uniform vec2 uResolution;',
     'uniform float uTime;',
     'uniform vec3 uSky;',
     'uniform vec3 uCloud;',
+    'uniform vec3 uCloudShadow;',
     'uniform vec3 uLight;',
+    'uniform vec3 uBg;',
     'uniform float uSpeed;',
+    'uniform float uDensity;',     // 0..1 how thick the clouds are
+    'uniform float uDayProgress;', // 0..1 (day vs night)
     'float hash(vec2 p) {',
         'p = fract(p * vec2(123.34, 456.21));',
         'p += dot(p, p + 45.32);',
@@ -80,10 +88,21 @@ var FRAG_SRC = [
         'vec2 p1 = uv * vec2(3.0, 1.7) + vec2(uTime * 0.012, uTime * 0.004);',
         'vec2 p2 = uv * vec2(5.0, 2.6) + vec2(uTime * 0.020, -uTime * 0.006);',
         'float n = fbm(p1 * uSpeed) * 0.6 + fbm(p2 * uSpeed) * 0.4;',
-        'float cloud = smoothstep(0.35, 0.75, n);',
-        'float horizon = smoothstep(0.0, 0.45, uv.y);',
-        'vec3 col = mix(uSky, uCloud, cloud * (1.0 - horizon * 0.3));',
-        'col = mix(col, uLight, cloud * horizon * 0.5);',
+        // Density threshold widens with uDensity (1 = always cloudy, 0 = clear sky)
+        'float thresh = mix(0.85, 0.30, uDensity);',
+        'float cloud = smoothstep(thresh - 0.10, thresh + 0.10, n);',
+        // Soft horizon: top of frame is more sky, bottom more clouds
+        'float horizon = smoothstep(0.0, 0.5, uv.y);',
+        // Sky gradient (top vs bottom)
+        'vec3 sky = mix(uBg, uSky, horizon);',
+        // Cloud body (lit top + shadow bottom)
+        'vec3 cloudCol = mix(uCloudShadow, uCloud, horizon);',
+        // Add light tint to the lit side
+        'cloudCol = mix(cloudCol, uLight, cloud * horizon * 0.4 * uDayProgress);',
+        // Final composite: sky where there's no cloud, cloud where there is
+        'vec3 col = mix(sky, cloudCol, cloud);',
+        // At night, blend everything toward bg color (darken)
+        'col = mix(col, mix(uBg, cloudCol, 0.3), (1.0 - uDayProgress) * 0.5);',
         'gl_FragColor = vec4(col, 1.0);',
     '}'
 ].join('\n');
@@ -108,34 +127,51 @@ function init(canvas) {
     var uTime = gl.getUniformLocation(prog, 'uTime');
     var uSky = gl.getUniformLocation(prog, 'uSky');
     var uCloud = gl.getUniformLocation(prog, 'uCloud');
+    var uCloudShadow = gl.getUniformLocation(prog, 'uCloudShadow');
     var uLight = gl.getUniformLocation(prog, 'uLight');
+    var uBg = gl.getUniformLocation(prog, 'uBg');
     var uSpeed = gl.getUniformLocation(prog, 'uSpeed');
+    var uDensity = gl.getUniformLocation(prog, 'uDensity');
+    var uDayProgress = gl.getUniformLocation(prog, 'uDayProgress');
 
     return {
         gl: gl, prog: prog, buf: buf, aPos: aPos,
         uRes: uRes, uTime: uTime, uSky: uSky, uCloud: uCloud,
-        uLight: uLight, uSpeed: uSpeed
+        uCloudShadow: uCloudShadow, uLight: uLight, uBg: uBg,
+        uSpeed: uSpeed, uDensity: uDensity, uDayProgress: uDayProgress
     };
 }
 
-function hex(r, g, b) { return [r/255, g/255, b/255]; }
+// Convert 24-bit int (0xRRGGBB) to [r,g,b] 0..1 floats.
+// Theme-agnostic: caller decides what colour value to pass in.
+function hex(rgb) {
+    return [((rgb >> 16) & 255) / 255,
+            ((rgb >> 8) & 255) / 255,
+            (rgb & 255) / 255];
+}
+
+// Cloud density per weather (0 = clear, 1 = overcast).
+// Names mirror the weather themes defined in background.html.
+var WEATHER_DENSITY = {
+    sunny: 0.20,
+    cloudy: 0.70,
+    stormy: 1.00,
+    night: 0.45
+};
 
 window.clouds2dRender = function(target) {
     if (!target || typeof target !== 'object') {
         console.error('clouds2d: invalid target');
         return;
     }
-    // Get or create the WebGL canvas
     var canvas = target.__clouds2dCanvas;
     if (!canvas) {
-        // Replace the target's content with a WebGL canvas
         canvas = document.createElement('canvas');
         canvas.style.position = 'absolute';
         canvas.style.top = '0';
         canvas.style.left = '0';
         canvas.style.width = '100%';
         canvas.style.height = '100%';
-        // Empty the target and insert the canvas as the only child
         while (target.firstChild) target.removeChild(target.firstChild);
         target.appendChild(canvas);
         target.style.position = 'relative';
@@ -164,20 +200,38 @@ window.clouds2dRender = function(target) {
     gl.uniform2f(s.uRes, canvas.width, canvas.height);
     gl.uniform1f(s.uTime, performance.now() / 1000);
 
-    var sky = [0.39, 0.54, 0.78];
-    var cloud = [0.43, 0.43, 0.43];
-    var light = [0.89, 0.87, 0.82];
-    var cfg = window.CONFIG || {};
-    var theme = (cfg.currentWeatherTheme || (cfg.weatherThemes && cfg.weatherThemes[cfg.theme])) || null;
-    if (theme) {
-        sky = hex((theme.skyColor >> 16) & 255, (theme.skyColor >> 8) & 255, theme.skyColor & 255);
-        cloud = hex((theme.cloudColor >> 16) & 255, (theme.cloudColor >> 8) & 255, theme.cloudColor & 255);
-        light = hex((theme.lightColor >> 16) & 255, (theme.lightColor >> 8) & 255, theme.lightColor & 255);
+    // Pull palette + weather from globals (set by animate() in background.html).
+    // No hardcoded fallbacks: until the parent has published a palette we
+    // skip the draw and leave the WebGL context cleared. This keeps the
+    // renderer 100% theme-agnostic — the parent fully owns colour decisions.
+    var pal = window.__currentPalette;
+    if (!pal) {
+        gl.clearColor(0, 0, 0, 1);
+        gl.clear(gl.COLOR_BUFFER_BIT);
+        return;
     }
-    gl.uniform3fv(s.uSky, sky);
-    gl.uniform3fv(s.uCloud, cloud);
-    gl.uniform3fv(s.uLight, light);
-    gl.uniform1f(s.uSpeed, 1.0);
+
+    var weather = window.__currentWeatherName;
+    var dayProgress = window.__currentDayProgress;
+    var themeSpeed = window.__currentThemeSpeed;
+
+    gl.uniform3fv(s.uSky, hex(pal.sky));
+    gl.uniform3fv(s.uCloud, hex(pal.cloud));
+    gl.uniform3fv(s.uCloudShadow, hex(pal.cloudShadow !== undefined ? pal.cloudShadow : pal.sky));
+    gl.uniform3fv(s.uLight, hex(pal.light));
+    gl.uniform3fv(s.uBg, hex(pal.bg));
+
+    var density = (weather && WEATHER_DENSITY[weather] !== undefined)
+        ? WEATHER_DENSITY[weather] : 0.5;
+    gl.uniform1f(s.uDensity, density);
+
+    var day = (typeof dayProgress === 'number')
+        ? Math.max(0, Math.min(1, dayProgress)) : 0.5;
+    gl.uniform1f(s.uDayProgress, day);
+
+    var speed = (typeof themeSpeed === 'number')
+        ? Math.max(0.1, Math.min(3, themeSpeed)) : 1.0;
+    gl.uniform1f(s.uSpeed, speed);
 
     gl.drawArrays(gl.TRIANGLES, 0, 3);
 };