From bb84178f20df16a8c5035b877165968a33ed165a Mon Sep 17 00:00:00 2001
From: the_fiddler <the_fiddler@ebc5dd9b-fb1d-0410-b6f8-d24c324e9604>
Date: Sat, 8 Mar 2008 17:35:58 +0000
Subject: [PATCH] Added detection of left and right shift/control/alt buttons.

---
 Source/OpenTK/Platform/Windows/API.cs     |  2 +-
 Source/OpenTK/Platform/Windows/WMInput.cs | 30 ++++++++++++++++++++---
 2 files changed, 28 insertions(+), 4 deletions(-)

diff --git a/Source/OpenTK/Platform/Windows/API.cs b/Source/OpenTK/Platform/Windows/API.cs
index 5c998123..059d2969 100644
--- a/Source/OpenTK/Platform/Windows/API.cs
+++ b/Source/OpenTK/Platform/Windows/API.cs
@@ -525,7 +525,7 @@ namespace OpenTK.Platform.Windows
 
         [System.Security.SuppressUnmanagedCodeSecurity]
         [DllImport("user32.dll", SetLastError = true)]
-        internal static extern SHORT GetAsyncKeyState(int vKey);
+        internal static extern SHORT GetAsyncKeyState(VirtualKeys vKey);
 
         #endregion
 
diff --git a/Source/OpenTK/Platform/Windows/WMInput.cs b/Source/OpenTK/Platform/Windows/WMInput.cs
index c4d4bfb1..44dfd3ec 100644
--- a/Source/OpenTK/Platform/Windows/WMInput.cs
+++ b/Source/OpenTK/Platform/Windows/WMInput.cs
@@ -110,18 +110,42 @@ namespace OpenTK.Platform.Windows
                 case WindowMessage.SYSKEYUP:
                     bool pressed = (WindowMessage)msg.Msg == WindowMessage.KEYDOWN ||
                                    (WindowMessage)msg.Msg == WindowMessage.SYSKEYDOWN;
+                    //bool left = (((int)msg.LParam) & 0x100000) == 0; // valid for Shift, Control and Menu presses.
                     switch ((VirtualKeys)msg.WParam)
                     {
                         case VirtualKeys.SHIFT:
-                            keyboard[Input.Key.ShiftLeft] = keyboard[Input.Key.ShiftRight] = pressed;
+                            // Win95 does not distinguish left/right constants (GetAsyncKeyState returns 0).
+                            // In this case, report both keys as down.
+                            bool left = Functions.GetAsyncKeyState(VirtualKeys.LSHIFT) != 0;
+                            bool right = Functions.GetAsyncKeyState(VirtualKeys.RSHIFT) != 0;
+                            if (left)
+                                keyboard[Input.Key.ShiftLeft] = pressed;
+                            if (right)
+                                keyboard[Input.Key.ShiftRight] = pressed;
+                            if (!left && !right)
+                                keyboard[Input.Key.ShiftLeft] = keyboard[Input.Key.ShiftRight] = pressed;
                             return;
 
                         case VirtualKeys.CONTROL:
-                            keyboard[Input.Key.ControlLeft] = keyboard[Input.Key.ControlRight] = pressed;
+                            left = Functions.GetAsyncKeyState(VirtualKeys.LCONTROL) != 0;
+                            right = Functions.GetAsyncKeyState(VirtualKeys.RCONTROL) != 0;
+                            if (left)
+                                keyboard[Input.Key.ControlLeft] = pressed;
+                            if (right)
+                                keyboard[Input.Key.ControlRight] = pressed;
+                            if (!left && !right)
+                                keyboard[Input.Key.ControlLeft] = keyboard[Input.Key.ControlRight] = pressed;
                             return;
 
                         case VirtualKeys.MENU:
-                            keyboard[Input.Key.AltLeft] = keyboard[Input.Key.AltRight] = pressed;
+                            left = Functions.GetAsyncKeyState(VirtualKeys.LMENU) != 0;
+                            right = Functions.GetAsyncKeyState(VirtualKeys.RMENU) != 0;
+                            if (left)
+                                keyboard[Input.Key.AltLeft] = pressed;
+                            if (right)
+                                keyboard[Input.Key.AltRight] = pressed;
+                            if (!left && !right)
+                                keyboard[Input.Key.AltLeft] = keyboard[Input.Key.AltRight] = pressed;
                             return;
 
                         default: