Sky color (#276)

* Adding background color for semantic segmentation and bad UI. Need to come back to this later.

* Updating UI

* Changing 'background' to 'sky' and improving tests.

* some UI polish

* Updating label config and PerceptionURP

* Adding new sky label to output when sky color is set.

Co-authored-by: Mohsen Kamalzadeh <>

com.unity.perception/Runtime/GroundTruth/Labelers/SemanticSegmentationLabeler.cs

             {
                 label_name = l.label,
                 pixel_value = l.color
-            }).ToArray();
+            });
+
+            if (labelConfig.skyColor != Color.black)
+            {
+                specs = specs.Append(new SemanticSegmentationSpec()
+                {
+                    label_name = "sky",
+                    pixel_value = labelConfig.skyColor
+                });
+            }
-                specs,
+                specs.ToArray(),
                 "pixel-wise semantic segmentation label",
                 "PNG",
                 id: Guid.Parse(annotationId));