From 4894497ce2a97af4dbff69897b0f619fa6c4c1a1 Mon Sep 17 00:00:00 2001
From: Erik Hofman <erik@ehofman.com>
Date: Sun, 7 Feb 2021 16:03:08 +0100
Subject: [PATCH] Update the way the snow thickness is calculated, otherwise
 there will never be snow

---
 src/Environment/climate.cxx | 18 +++++++++---------
 1 file changed, 9 insertions(+), 9 deletions(-)

diff --git a/src/Environment/climate.cxx b/src/Environment/climate.cxx
index 611f79c14..11f32bb26 100644
--- a/src/Environment/climate.cxx
+++ b/src/Environment/climate.cxx
@@ -867,21 +867,21 @@ void FGClimate::set_environment()
     }
     else
     {
-        double wetness = std::max(_gl.precipitation - 20.0, 0.0);
-        wetness = powf(sin(atan(12.0*wetness/990.0)), 2.0);
+        double wetness = 12.0*_gl.precipitation/990.0;
+        wetness = pow(sin(atan(SGD_PI*wetness)), 2.0);
 
-        _set(_dust_cover, 0.0);
+        _dust_cover = 0.0;
 
-        if (_gl.temperature_mean < -5.0) {
-            _set(_snow_thickness, wetness);
+        if (_gl.temperature_mean < 5.0) {
+            _snow_thickness = wetness;
         } else {
-            _set(_snow_thickness, 0.0);
+            _snow_thickness = 0.0;
         }
 
-        if (_gl.temperature_mean > 0.0) {
-            _set(_wetness, pow(wetness, 2.0));
+        if (_gl.temperature_mean < 0.0) {
+            _wetness = 0.0;
         } else {
-            _set(_wetness, 0.0);
+            _wetness = wetness;
         }
 
         double cover = std::min(_gl.precipitation_annual, 990.0)/990.0;