From 8798fe3b48cf0ce707262165c3ccf58ea3264dab Mon Sep 17 00:00:00 2001
From: cosmonaut <evan@moonside.games>
Date: Thu, 6 Aug 2020 16:37:24 -0700
Subject: [PATCH] clamp arcball pitch

---
 KavTest/KavTestGame.cs              |  4 ++--
 KavTest/Utility/ArcballTransform.cs |  3 ++-
 KavTest/Utility/MathHelper.cs       | 10 ++++++++++
 3 files changed, 14 insertions(+), 3 deletions(-)
 create mode 100644 KavTest/Utility/MathHelper.cs

diff --git a/KavTest/KavTestGame.cs b/KavTest/KavTestGame.cs
index d6fbb55..a7b8bac 100644
--- a/KavTest/KavTestGame.cs
+++ b/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
diff --git a/KavTest/Utility/ArcballTransform.cs b/KavTest/Utility/ArcballTransform.cs
index 866c89a..7979788 100644
--- a/KavTest/Utility/ArcballTransform.cs
+++ b/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)
diff --git a/KavTest/Utility/MathHelper.cs b/KavTest/Utility/MathHelper.cs
new file mode 100644
index 0000000..06b772a
--- /dev/null
+++ b/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);
+        }
+    }
+}