clouds: raise cloud top to 20 km and disable terrain occlusion for test

config.js

@@ -144,7 +144,7 @@ window.CONFIG = {
     // altitude so aircraft fly above the deck.
     clouds: {
         enabled: true,
-        top: 1.0,                 // ~12.9 km
+        top: 1.55,                // ~20 km test deck
         bottom: -0.2,             // ~-2.6 km (deck base slightly below terrain)
         // Coverage per weather level, 0 = clear, 1 = overcast. Only the
         // levels listed here override the built-in defaults

vendor/clouds3d.js

@@ -6855,7 +6855,7 @@ window.clouds3dRender = function(target) {
         gl.activeTexture(gl.TEXTURE7);
         gl.bindTexture(gl.TEXTURE_2D, terrainDistTex || null);
         gl.uniform1i(s.uTerrainDistTex, 7);
-        gl.uniform1f(s.uTerrainDistOk, (terrainDistOk && terrainDistTex) ? 1.0 : 0.0);
+        gl.uniform1f(s.uTerrainDistOk, 0.0); // test: clouds ignore terrain occlusion
         gl.disable(gl.DEPTH_TEST);
         gl.depthMask(false);
         gl.enable(gl.BLEND);