From 2e3a331d1345e88b6406d79328d489be1dc263a3 Mon Sep 17 00:00:00 2001
From: cosmonaut <evan@moonside.games>
Date: Thu, 6 Aug 2020 16:28:47 -0700
Subject: [PATCH] disable mouse polling when window is inactive

---
 KavTest/Engines/InputEngine.cs | 16 +++++++++++++---
 KavTest/KavTestGame.cs         |  2 +-
 2 files changed, 14 insertions(+), 4 deletions(-)

diff --git a/KavTest/Engines/InputEngine.cs b/KavTest/Engines/InputEngine.cs
index e9430ab..398555a 100644
--- a/KavTest/Engines/InputEngine.cs
+++ b/KavTest/Engines/InputEngine.cs
@@ -13,6 +13,13 @@ namespace KavTest.Engines
     )]
     public class InputEngine : Engine
     {
+        private Game Game { get; }
+
+        public InputEngine(Game game)
+        {
+            Game = game;
+        }
+
         public override void Update(double dt)
         {
             var keyboardState = Keyboard.GetState();
@@ -38,10 +45,13 @@ namespace KavTest.Engines
                 SendMessage(new MoveCameraMessage(new Vector3(5, 0, 0)));
             }
 
-            if (SomeComponent<CameraComponent>())
+            if (Game.IsActive)
             {
-                var cameraEntity = ReadEntity<CameraComponent>();
-                SendMessage(new RotateCameraMessage(cameraEntity, -mouseState.X, -mouseState.Y));
+                if (SomeComponent<CameraComponent>())
+                {
+                    var cameraEntity = ReadEntity<CameraComponent>();
+                    SendMessage(new RotateCameraMessage(cameraEntity, -mouseState.X, -mouseState.Y));
+                }
             }
         }
     }
diff --git a/KavTest/KavTestGame.cs b/KavTest/KavTestGame.cs
index f9b9107..d6fbb55 100644
--- a/KavTest/KavTestGame.cs
+++ b/KavTest/KavTestGame.cs
@@ -50,7 +50,7 @@ namespace KavTest
                 Smuggler.Importer.ImportGLB(GraphicsDevice, File.OpenRead("Content/rustysphere.glb"))
             );
 
-            WorldBuilder.AddEngine(new InputEngine());
+            WorldBuilder.AddEngine(new InputEngine(this));
             WorldBuilder.AddEngine(new AngularVelocityEngine());
             WorldBuilder.AddEngine(new MotionEngine());
             WorldBuilder.AddEngine(new CameraEngine());