Added cloud state message

Signed-off-by: Markus Waldmann <Markus.Waldmann@stud.hs-kempten.de>

Author: Markus Waldmann

osi_environment.proto

@@ -105,6 +105,10 @@ message EnvironmentalConditions
     //
     optional Wind wind = 11;
 
+    // Definition of cloud states and the skybox.
+    //
+    optional CloudState cloud_state = 10;
+
     // Definition of discretized precipitation states according to [1].
     // (I = Intensity of precipitation in mm per hour mm/h)
     //
@@ -346,4 +350,78 @@ message EnvironmentalConditions
         //
         optional double speed = 2;
     }
+
+    // Definition of the cloud state, i.e. cloud state and sky visualization settings.
+    //
+    // The total degree of coverage indicates how large the part of the sky vault is which is covered
+    // with clouds altogether. It is given in eighths, because this division is easier to estimate
+    // for the observer. 0 eighths means that there are no traces of clouds in the sky,
+    // 4 eighths means that the sky is covered with clouds up to half, 8 eighths means that the sky is
+    // completely covered with clouds and no sky blue can be recognized.
+    //
+    // For cloud determination, the observer will choose a location from which he can overlook the entire sky.
+    // When determining the total cloud cover, all clouds or parts of clouds, regardless of height and genus,
+    // that are above his location will be added. Aircraft contrails are also counted as cloud cover if they remain
+    // in the sky for more than 15 minutes. On the other hand, fog is not counted as cloud cover.
+    //
+    // With a little practice, the observer can easily determine the total amount of cloud cover.
+    // Problems occur only with scattered clouds or many single clouds (cumulus).
+    // Their cloud cover is often overestimated. On the other hand,
+    // the coverage of thin ice clouds (cirrus) is often underestimated.[3]
+    //
+    // \par References:
+    // [1] ISO 15469:2004(E) / CIE S 011/E:2003 : Spatial distribution of skylight
+    // [2] https://de.wikipedia.org/wiki/Bewölkung
+    // [3] https://www.dwd.de/DE/service/lexikon/Functions/glossar.html?lv2=100932&lv3=101016
+    //
+    enum CloudState
+    {
+        // Cloud State is unknown (must not be used in ground truth).
+        //
+        CLOUD_STATE_UNKNOWN = 0;
+
+        // Other (unspecified but known) CloudState.
+        //
+        CLOUD_STATE_OTHER = 1;
+
+        // Cloudless (0/8)
+        //
+        CLOUD_STATE_CLOUDLESS = 2;
+
+        // Sunny (1/8)
+        //
+        CLOUD_STATE_SUNNY = 3;
+
+        // Serene (2/8))
+        //
+        CLOUD_STATE_SERENE = 4;
+
+        // Slightly Cloudy (3/8)
+        //
+        CLOUD_STATE_SLIGHTLYCLOUDY = 5;
+
+        // Light Cloudy (4/8)
+        //
+        CLOUD_STATE_LIGHTCLOUDY = 6;
+
+        // Cloudy (5/8)
+        //
+        CLOUD_STATE_CLOUDY = 7;
+
+        // Heavy Cloudy (6/8)
+        //
+        CLOUD_STATE_HEAVYCLOUDY = 8;
+
+        // Almost Covered (7/8)
+        //
+        CLOUD_STATE_ALMOSTCOVERED = 9;
+
+        // Covered (8/8)
+        //
+        CLOUD_STATE_COVERED = 10;
+
+        // No Sky
+        //
+        CLOUD_STATE_NOSKY = 11;
+    }
 }