Fix mouse input on HiDPI monitors (#927)

OpenToolkit.GraphicsLibraryFramework/GLFW.cs

@@ -1099,6 +1099,49 @@ namespace OpenToolkit.GraphicsLibraryFramework
             bottom = b;
         }
 
+        /// <summary>
+        /// <para>
+        /// This function retrieves the content scale for the specified window.
+        /// </para>
+        /// <para>
+        /// The content scale is the ratio between the current DPI and the platform's default DPI.
+        /// This is especially important for text and any UI elements.
+        /// If the pixel dimensions of your UI scaled by this look appropriate on your machine then it should
+        /// appear at a reasonable size on other machines regardless of their DPI and scaling settings.
+        /// This relies on the system DPI and scaling settings being somewhat correct.
+        /// </para>
+        ///
+        /// <para>
+        /// On systems where each monitors can have its own content scale,
+        /// the window content scale will depend on which monitor the system considers the window to be on.
+        /// </para>
+        /// </summary>
+        /// <param name="window">The window to query.</param>
+        /// <param name="xScale">
+        /// Where to store the x-axis content scale, or <c>out _</c>.
+        /// </param>
+        /// <param name="yScale">
+        /// Where to store the y-axis content scale, or <c>out _</c>.
+        /// </param>
+        /// <remarks>
+        /// <para>
+        /// This function must only be called from the main thread.
+        /// </para>
+        /// <para>
+        /// Possible errors include <see cref="ErrorCode.NotInitialized"/> and <see cref="ErrorCode.PlatformError"/>.
+        /// </para>
+        /// </remarks>
+        public static unsafe void GetWindowContentScale(
+            Window* window,
+            out float xScale,
+            out float yScale)
+        {
+            float x, y;
+            glfwGetWindowContentScale(window, &x, &y);
+            xScale = x;
+            yScale = y;
+        }
+
         /// <summary>
         /// <para>
         /// This function returns the opacity of the window, including any decorations.
@@ -4422,6 +4465,31 @@ namespace OpenToolkit.GraphicsLibraryFramework
             return glfwSetWindowIconifyCallback(window, Marshal.GetFunctionPointerForDelegate(callback));
         }
 
+        /// <summary>
+        /// <para>
+        /// This function sets the window content scale callback of the specified window,
+        /// which is called when the content scale of the specified window changes.
+        /// </para>
+        /// </summary>
+        /// <param name="window">The window whose content scale changed.</param>
+        /// <param name="xscale">The new x-axis content scale of the window. </param>
+        /// <param name="yscale">The new y-axis content scale of the window. </param>
+        /// <remarks>
+        /// <para>
+        /// This function must only be called from the main thread.
+        /// </para>
+        /// <para>
+        /// Possible errors include <see cref="ErrorCode.NotInitialized"/>.
+        /// </para>
+        /// </remarks>
+        /// <seealso cref="GetWindowContentScale"/>
+        public static unsafe IntPtr SetWindowContentScaleCallback(
+            Window* window,
+            GLFWCallbacks.WindowContentScaleCallback callback)
+        {
+            return glfwSetWindowContentScaleCallback(window, Marshal.GetFunctionPointerForDelegate(callback));
+        }
+
         /// <summary>
         /// <para>
         /// This function sets the monitor that the window uses for full screen mode or,

OpenToolkit.GraphicsLibraryFramework/GLFWCallbacks.cs

@@ -1,4 +1,4 @@
-//
+//
 // GLFWCallbacks.cs
 //
 // Copyright (C) 2019 OpenTK
@@ -167,5 +167,14 @@ namespace OpenToolkit.GraphicsLibraryFramework
         /// </summary>
         /// <param name="window">The window that needs to be refreshed.</param>
         public delegate void WindowRefreshCallback(Window* window);
+
+        /// <summary>
+        /// This is the function pointer type for window content scale callbacks. 
+        /// </summary>
+        /// <param name="window">The window whose content scale changed. </param>
+        /// <param name="xscale">The new x-axis content scale of the window. </param>
+        /// <param name="yscale">The new y-axis content scale of the window.</param>
+        /// <seealso cref="GLFW.SetWindowContentScaleCallback"/>
+        public delegate void WindowContentScaleCallback(Window* window, float xscale, float yscale);
     }
 }

OpenToolkit.GraphicsLibraryFramework/GLFWNative.cs

@@ -1,4 +1,4 @@
-using System;
+using System;
 using System.Runtime.InteropServices;
 
 namespace OpenToolkit.GraphicsLibraryFramework
@@ -103,6 +103,9 @@ namespace OpenToolkit.GraphicsLibraryFramework
         [DllImport(LibraryName)]
         public static extern void glfwGetWindowFrameSize(Window* window, int* left, int* top, int* right, int* bottom);
 
+        [DllImport(LibraryName)]
+        public static extern void glfwGetWindowContentScale(Window* window, float* xscale, float* yscale);
+
         [DllImport(LibraryName)]
         public static extern float glfwGetWindowOpacity(Window* window);
 
@@ -340,6 +343,9 @@ namespace OpenToolkit.GraphicsLibraryFramework
         [DllImport(LibraryName)]
         public static extern IntPtr glfwSetWindowIconifyCallback(Window* window, IntPtr callback);
 
+        [DllImport(LibraryName)]
+        public static extern IntPtr glfwSetWindowContentScaleCallback(Window* window, IntPtr callback);
+
         [DllImport(LibraryName)]
         public static extern void glfwSetWindowTitle(Window* window, byte* title);
 

Robust.Client/Graphics/Clyde/Clyde.Windowing.cs

@@ -1,4 +1,4 @@
-using System;
+using System;
 using System.Collections.Generic;
 using System.Diagnostics;
 using System.Linq;
@@ -36,6 +36,7 @@ namespace Robust.Client.Graphics.Clyde
         private GLFWCallbacks.ScrollCallback _scrollCallback;
         private GLFWCallbacks.WindowCloseCallback _windowCloseCallback;
         private GLFWCallbacks.WindowSizeCallback _windowSizeCallback;
+        private GLFWCallbacks.WindowContentScaleCallback _windowContentScaleCallback;
 
         private bool _glfwInitialized = false;
 
@@ -43,6 +44,7 @@ namespace Robust.Client.Graphics.Clyde
         private Window* _glfwWindow;
 
         private Vector2i _screenSize;
+        private Vector2 _windowScale;
         private Thread _mainThread;
 
         private Vector2 _lastMousePos;
@@ -118,6 +120,7 @@ namespace Robust.Client.Graphics.Clyde
             GLFW.SetWindowSizeCallback(_glfwWindow, _windowSizeCallback);
             GLFW.SetScrollCallback(_glfwWindow, _scrollCallback);
             GLFW.SetMouseButtonCallback(_glfwWindow, _mouseButtonCallback);
+            GLFW.SetWindowContentScaleCallback(_glfwWindow, _windowContentScaleCallback);
 
             GLFW.MakeContextCurrent(_glfwWindow);
 
@@ -126,6 +129,9 @@ namespace Robust.Client.Graphics.Clyde
             GLFW.GetFramebufferSize(_glfwWindow, out var fbW, out var fbH);
             _screenSize = (fbW, fbH);
 
+            GLFW.GetWindowContentScale(_glfwWindow, out var scaleX, out var scaleY);
+            _windowScale = (scaleX, scaleY);
+
             InitGLContext();
 
             // Initializing OTK 3 seems to mess with the current context, so ensure it's still set.
@@ -218,7 +224,7 @@ namespace Robust.Client.Graphics.Clyde
 
         private void OnGlfwCursorPos(Window* window, double x, double y)
         {
-            var newPos = new Vector2((float) x, (float) y);
+            var newPos = new Vector2((float) x, (float) y) * _windowScale;
             var delta = newPos - _lastMousePos;
             _lastMousePos = newPos;
 
@@ -288,6 +294,11 @@ namespace Robust.Client.Graphics.Clyde
             OnWindowResized?.Invoke(new WindowResizedEventArgs(oldSize, _screenSize));
         }
 
+        private void OnGlfwWindownContentScale(Window *window, float xScale, float yScale)
+        {
+            _windowScale = (xScale, yScale);
+        }
+
         private void StoreCallbacks()
         {
             _errorCallback = OnGlfwError;
@@ -298,6 +309,7 @@ namespace Robust.Client.Graphics.Clyde
             _scrollCallback = OnGlfwScroll;
             _windowCloseCallback = OnGlfwWindowClose;
             _windowSizeCallback = OnGlfwWindowSize;
+            _windowContentScaleCallback = OnGlfwWindownContentScale;
         }
 
         public override void SetWindowTitle(string title)