clamp arcball pitch

KavTest/KavTestGame.cs

@@ -83,13 +83,13 @@ namespace KavTest
             WorldBuilder.SetComponent(cameraEntity, new ArcballTransformComponent(
                 new ArcballTransform(
                     new Vector3(0, 0, -10),
-                    MathHelper.Pi,
+                    Microsoft.Xna.Framework.MathHelper.Pi,
                     0
                 )
             ));
             WorldBuilder.SetComponent(cameraEntity, new CameraComponent(
                 Matrix.CreatePerspectiveFieldOfView(
-                    MathHelper.PiOver4,
+                    Microsoft.Xna.Framework.MathHelper.PiOver4,
                     16f / 9f,
                     0.1f,
                     200f

KavTest/Utility/ArcballTransform.cs

@@ -25,7 +25,8 @@ namespace KavTest
 
         public ArcballTransform RotateLocal(float deltaYaw, float deltaPitch)
         {
-            return new ArcballTransform(Position, Yaw + deltaYaw, Pitch + deltaPitch);
+            var newPitch = MathHelper.Clamp(Pitch + deltaPitch, -Microsoft.Xna.Framework.MathHelper.PiOver2, Microsoft.Xna.Framework.MathHelper.PiOver2);
+            return new ArcballTransform(Position, Yaw + deltaYaw, newPitch);
         }
 
         public ArcballTransform TranslateLocal(Vector3 localTranslation)

KavTest/Utility/MathHelper.cs

@@ -0,0 +1,10 @@
+namespace KavTest
+{
+    public static class MathHelper
+    {
+        public static float Clamp(float value, float min, float max)
+        {
+            return System.Math.Min(System.Math.Max(value, min), max);
+        }
+    }
+}