atmosphere: add altitude-thinning distance haze

config.js

@@ -316,8 +316,16 @@ window.CONFIG = {
         physicalSky: true,        // Rayleigh sky scattering instead of pure theme gradient
         rayleighGain: 8.0,        // exposure for the physical sky term
         distanceFog: false,       // legacy aerial perspective is off
+        haze: {
+            enabled: true,
+            heightKm: 60,
+            scaleHeightKm: 8.5,
+            density: 0.25,
+            grayTau: 1.2,
+            gain: 1.0
+        },
         model: {
-            enabled: false        // volumetric atmosphere/fog removed
+            enabled: false        // legacy full atmosphere model remains off
         },
         hazeResidual: 0.30,       // surface colour surviving at the full fog distance
         cloudBrightness: 1.0,     // cloud albedo (theme hue, brightness from the model)

vendor/clouds3d.js

@@ -364,7 +364,7 @@ var FRAG_SRC = [
             'for (int i = 0; i < 32; i++) {',
                 'vec3 p = ro + rd * t;',
                 'float alt = max(0.0, length(p - C) - R);',
-                'float dens = exp(-alt / Hs);',
+                'float dens = exp(-alt / Hs) / Hs;',
                 'float dtau = uAtmoDensity * dens * step;',
                 'float transBefore = exp(-tau);',
                 'float grayMix = clamp(tau / max(0.01, uAtmoGrayTau), 0.0, 1.0);',
@@ -2427,19 +2427,32 @@ var ATMO_HAZE_RESIDUAL = (typeof ATMO.hazeResidual === 'number')
     ? Math.max(0.02, Math.min(0.95, ATMO.hazeResidual)) : 0.30;
 var ATMO_DISTANCE_FOG = ATMO.distanceFog !== false;
 var ATMO_MODEL = ATMO.model || {};
-var ATMO_MODEL_ON = ATMO_MODEL.enabled === true;
+var HAZE_CFG = ATMO.haze || {};
-var ATMO_MODEL_HEIGHT_KM = (typeof ATMO_MODEL.heightKm === 'number')
+var ATMO_MODEL_ON = (typeof HAZE_CFG.enabled === 'boolean')
-    ? Math.max(1.0, Math.min(80.0, ATMO_MODEL.heightKm)) : 35.0;
+    ? HAZE_CFG.enabled
+    : (ATMO_MODEL.enabled === true);
+var ATMO_MODEL_HEIGHT_KM = (typeof HAZE_CFG.heightKm === 'number')
+    ? Math.max(1.0, Math.min(120.0, HAZE_CFG.heightKm))
+    : ((typeof ATMO_MODEL.heightKm === 'number')
+        ? Math.max(1.0, Math.min(80.0, ATMO_MODEL.heightKm)) : 60.0);
 var ATMO_MODEL_HEIGHT_UNITS = ATMO_MODEL_HEIGHT_KM / KM_PER_TILE;
-var ATMO_MODEL_SCALE_HEIGHT_KM = (typeof ATMO_MODEL.scaleHeightKm === 'number')
+var ATMO_MODEL_SCALE_HEIGHT_KM = (typeof HAZE_CFG.scaleHeightKm === 'number')
-    ? Math.max(1.0, Math.min(30.0, ATMO_MODEL.scaleHeightKm)) : 8.5;
+    ? Math.max(1.0, Math.min(30.0, HAZE_CFG.scaleHeightKm))
+    : ((typeof ATMO_MODEL.scaleHeightKm === 'number')
+        ? Math.max(1.0, Math.min(30.0, ATMO_MODEL.scaleHeightKm)) : 8.5);
 var ATMO_MODEL_SCALE_HEIGHT_UNITS = ATMO_MODEL_SCALE_HEIGHT_KM / KM_PER_TILE;
-var ATMO_MODEL_DENSITY = (typeof ATMO_MODEL.density === 'number')
+var ATMO_MODEL_DENSITY = (typeof HAZE_CFG.density === 'number')
-    ? Math.max(0.01, Math.min(5.0, ATMO_MODEL.density)) : 0.12;
+    ? Math.max(0.01, Math.min(5.0, HAZE_CFG.density))
-var ATMO_MODEL_GRAY_TAU = (typeof ATMO_MODEL.grayTau === 'number')
+    : ((typeof ATMO_MODEL.density === 'number')
-    ? Math.max(0.1, Math.min(10.0, ATMO_MODEL.grayTau)) : 1.5;
+        ? Math.max(0.01, Math.min(5.0, ATMO_MODEL.density)) : 0.25);
-var ATMO_MODEL_GAIN = (typeof ATMO_MODEL.gain === 'number')
+var ATMO_MODEL_GRAY_TAU = (typeof HAZE_CFG.grayTau === 'number')
-    ? Math.max(0.1, Math.min(5.0, ATMO_MODEL.gain)) : 2.0;
+    ? Math.max(0.1, Math.min(10.0, HAZE_CFG.grayTau))
+    : ((typeof ATMO_MODEL.grayTau === 'number')
+        ? Math.max(0.1, Math.min(10.0, ATMO_MODEL.grayTau)) : 1.2);
+var ATMO_MODEL_GAIN = (typeof HAZE_CFG.gain === 'number')
+    ? Math.max(0.1, Math.min(5.0, HAZE_CFG.gain))
+    : ((typeof ATMO_MODEL.gain === 'number')
+        ? Math.max(0.1, Math.min(5.0, ATMO_MODEL.gain)) : 1.0);
 var CURV_CFG = (window.CONFIG && window.CONFIG.curvature) || {};
 var CURVATURE_ON = CURV_CFG.enabled !== false;
 var CURV_EXAG = (typeof CURV_CFG.exaggeration === 'number')
@@ -6364,6 +6377,14 @@ window.clouds3dRender = function(target) {
     }
 
     if (ATMO_MODEL_ON) {
+        gl.useProgram(s.prog);
+        gl.bindBuffer(gl.ARRAY_BUFFER, s.buf);
+        gl.enableVertexAttribArray(s.aPos);
+        gl.vertexAttribPointer(s.aPos, 2, gl.FLOAT, false, 0, 0);
+        gl.disable(gl.DEPTH_TEST);
+        gl.depthMask(false);
+        gl.enable(gl.BLEND);
+        gl.blendFunc(gl.SRC_ALPHA, gl.ONE_MINUS_SRC_ALPHA);
         gl.uniform1i(s.uMode, 2);
         gl.drawArrays(gl.TRIANGLES, 0, 3);
     }