skybox cleanup

Assets/ScriptableRenderLoop/common/SkyboxHelper.cs

 		CommandBuffer cmd = new CommandBuffer();
 		cmd.name = "Skybox";
 
-		Light sunLight = RenderSettings.sun;
-		Color sunColor = new Color(0, 0, 0);
-		Vector3 sunDir = new Vector3(0, 0, -1);
+		Material mat = RenderSettings.skybox;
-		if (sunLight != null)
+		if (mat == null)
-			sunColor = sunLight.color;
-			Transform xform = sunLight.transform;
-			sunDir = xform.TransformDirection(sunDir);
+			return;
-
-		Material mat = RenderSettings.skybox;
 
 		bool looksLikeSixSidedShader = true;
 		looksLikeSixSidedShader &= (mat.passCount == 6); // should have six passes
 			{
 				CreateMesh();
 			}
-
-			cmd.SetGlobalVector("_LightColor0", sunColor);
-			cmd.SetGlobalVector("_WorldSpaceLightPos0", sunDir);
 			
 			float dist = camera.farClipPlane * 10.0f;