fix available getter bug.

Assets/uDesktopDuplication/Scripts/Lib.cs

@@ -50,7 +50,7 @@ public static class Lib
     [DllImport("uDesktopDuplication")]
     public static extern IntPtr GetRenderEventFunc();
     [DllImport("uDesktopDuplication")]
-    public static extern bool IsAvailable();
+    public static extern bool IsAvailable(int id);
     [DllImport("uDesktopDuplication")]
     public static extern void GetName(int id, StringBuilder buf, int len);
     [DllImport("uDesktopDuplication")]

Assets/uDesktopDuplication/Scripts/Monitor.cs

@@ -23,7 +23,7 @@ public class Monitor
 
     public bool available
     {
-        get { return Lib.IsAvailable(); }
+        get { return Lib.IsAvailable(id); }
     }
 
     public string name

Assets/uDesktopDuplication/Scripts/Texture.cs

@@ -50,6 +50,7 @@ public class Texture : MonoBehaviour
 
     void Update()
     {
+        Debug.Log(monitor.available);
         monitor.shouldBeUpdated = true;
         UpdateMaterial();
     }