Fixing sky material when luminance is 0

materialsLibrary/dist/babylon.skyMaterial.js

@@ -169,7 +169,9 @@ var BABYLON;
                 this._cameraPosition.z = cameraWorldMatrix.m[14];
                 this._effect.setVector3("cameraPosition", this._cameraPosition);
             }
-            this._effect.setFloat("luminance", this.luminance);
+            if (this.luminance > 0) {
+                this._effect.setFloat("luminance", this.luminance);
+            }
             this._effect.setFloat("turbidity", this.turbidity);
             this._effect.setFloat("rayleigh", this.rayleigh);
             this._effect.setFloat("mieCoefficient", this.mieCoefficient);

materialsLibrary/materials/sky/babylon.skyMaterial.ts

@@ -223,7 +223,10 @@ module BABYLON {
                 this._effect.setVector3("cameraPosition", this._cameraPosition);
             }
             
-            this._effect.setFloat("luminance", this.luminance);
+            if (this.luminance > 0) {
+                this._effect.setFloat("luminance", this.luminance);
+            }
+            
 			this._effect.setFloat("turbidity", this.turbidity);
 			this._effect.setFloat("rayleigh", this.rayleigh);
 			this._effect.setFloat("mieCoefficient", this.mieCoefficient);