feat: wait for terrain before drawing clouds

config.js

@@ -335,6 +335,10 @@ window.CONFIG = {
             start: 0.35,          // world units: clouds fade out very close to camera
             end: 2.5              // full density from this distance onward
         },
+        // Delay the volumetric cloud pass until the DEM/terrain mesh is
+        // ready. This avoids clouds appearing over an unfinished ground model.
+        waitForTerrain: true,     // false = draw clouds immediately
+        // waitForTerrain: false
         // Coverage per weather level, 0 = clear, 1 = overcast. Only the
         // levels listed here override the built-in defaults
         // (sunny 0.20, cloudy 0.70, stormy 0.80, night 0.45). Live weather

vendor/clouds3d.js

@@ -1504,6 +1504,10 @@ var CLOUD_NEAR_FADE_CFG = (window.CONFIG && window.CONFIG.clouds && window.CONFI
 var CLOUD_NEAR_FADE_START = (typeof CLOUD_NEAR_FADE_CFG.start === 'number') ? Math.max(0, CLOUD_NEAR_FADE_CFG.start) : 0.35;
 var CLOUD_NEAR_FADE_END = Math.max(CLOUD_NEAR_FADE_START + 0.1, (typeof CLOUD_NEAR_FADE_CFG.end === 'number') ? CLOUD_NEAR_FADE_CFG.end : 2.5);
 var CLOUDS_ON = !(window.CONFIG && window.CONFIG.clouds && window.CONFIG.clouds.enabled === false);
+var CLOUDS_WAIT_FOR_TERRAIN = !(window.CONFIG && window.CONFIG.clouds && window.CONFIG.clouds.waitForTerrain === false);
+function cloudsActive() {
+    return CLOUDS_ON && (!CLOUDS_WAIT_FOR_TERRAIN || (elevTexture && terrainVbo));
+}
 var CLOUD_WIND_CFG = (window.CONFIG && window.CONFIG.clouds && window.CONFIG.clouds.wind) || {};
 var CLOUD_WIND_SCALE = (typeof CLOUD_WIND_CFG.speedScale === 'number') ? Math.max(0, CLOUD_WIND_CFG.speedScale) : 80;
 var CLOUD_WIND_MIN = (typeof CLOUD_WIND_CFG.minSpeed === 'number') ? Math.max(0, CLOUD_WIND_CFG.minSpeed) : 0.004;
@@ -7342,7 +7346,7 @@ window.clouds3dRender = function(target) {
     gl.uniform1f(s.uAirHazeMaxAlpha, AIR_HAZE_MAX_ALPHA);
     gl.uniform3f(s.uAirHazeColor, _airHazeColor[0], _airHazeColor[1], _airHazeColor[2]);
     gl.uniform1i(s.uTerrainDistTex, 7);
-    gl.uniform1f(s.uCloudsOn, CLOUDS_ON ? 1.0 : 0.0);
+    gl.uniform1f(s.uCloudsOn, cloudsActive() ? 1.0 : 0.0);
     gl.uniform1f(s.uFrontHazeOn, FRONT_HAZE_ON ? 1.0 : 0.0);
     gl.uniform1f(s.uFrontHazeDensity, FRONT_HAZE_DENSITY);
     gl.uniform1f(s.uFrontHazeScaleHeightUnits, FRONT_HAZE_SCALE_HEIGHT_UNITS);
@@ -7657,7 +7661,7 @@ window.clouds3dRender = function(target) {
         gl.uniform1f(terr.uCloudBot, CLOUD_BOT);
         gl.uniform1f(terr.uCloudTop, CLOUD_TOP);
         gl.uniform1f(terr.uDensity, density);
-        gl.uniform1f(terr.uCloudShadowOn, ATMO_CLOUD_SHADOWS ? 1.0 : 0.0);
+        gl.uniform1f(terr.uCloudShadowOn, (ATMO_CLOUD_SHADOWS && cloudsActive()) ? 1.0 : 0.0);
         gl.uniform1f(terr.uCloudShadowDensity, ATMO_CS_DENSITY);
         gl.uniform1f(terr.uCloudShadowFloor, ATMO_CS_FLOOR);
         gl.uniform1f(terr.uCloudShadowAmbient, ATMO_CS_AMBIENT);
@@ -7720,7 +7724,7 @@ window.clouds3dRender = function(target) {
             gl.enableVertexAttribArray(terr.aColor);
             gl.vertexAttribPointer(terr.aColor, 3, gl.FLOAT, false, STRIDE, 32);
         }
-        var distPassOk = (FRONT_HAZE_ON || CLOUDS_ON) && ensureTerrainDistFbo(gl, canvas.width, canvas.height);
+        var distPassOk = (FRONT_HAZE_ON || cloudsActive()) && ensureTerrainDistFbo(gl, canvas.width, canvas.height);
         if (distPassOk) {
             gl.bindFramebuffer(gl.FRAMEBUFFER, terrainDistFbo);
             gl.viewport(0, 0, terrainDistW, terrainDistH);
@@ -8017,7 +8021,7 @@ window.clouds3dRender = function(target) {
         gl.drawArrays(gl.TRIANGLES, 0, 3);
     }
 
-    if (CLOUDS_ON) {
+    if (cloudsActive()) {
         gl.useProgram(s.prog);
         gl.bindBuffer(gl.ARRAY_BUFFER, s.buf);
         gl.enableVertexAttribArray(s.aPos);