From 6c1e3fd84c35ba212b1eaae75ac13675b5e7f516 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Camilla=20L=C3=B6wy?= <elmindreda@elmindreda.org>
Date: Mon, 29 Jan 2024 18:03:47 +0100
Subject: [PATCH] Win32: Use existing cursor creation path

---
 src/win32_init.c   | 52 +++-------------------------------------------
 src/win32_window.c | 28 +++++++++++++++++++++++++
 2 files changed, 31 insertions(+), 49 deletions(-)

diff --git a/src/win32_init.c b/src/win32_init.c
index 25fde325..4a75cce6 100644
--- a/src/win32_init.c
+++ b/src/win32_init.c
@@ -430,46 +430,6 @@ static GLFWbool createHelperWindow(void)
    return GLFW_TRUE;
 }
 
-// Creates the blank cursor
-//
-static void createBlankCursor(void)
-{
-    // HACK: Create a transparent cursor as using the NULL cursor breaks
-    //       using SetCursorPos when connected over RDP
-    int cursorWidth = GetSystemMetrics(SM_CXCURSOR);
-    int cursorHeight = GetSystemMetrics(SM_CYCURSOR);
-    unsigned char* andMask = _glfw_calloc(cursorWidth * cursorHeight / 8, sizeof(unsigned char));
-    unsigned char* xorMask = _glfw_calloc(cursorWidth * cursorHeight / 8, sizeof(unsigned char));
-
-    if (andMask != NULL && xorMask != NULL) {
-
-        memset(andMask, 0xFF, (size_t)(cursorWidth * cursorHeight / 8));
-
-        // Cursor creation might fail, but that's fine as we get NULL in that case,
-        // which serves as an acceptable fallback blank cursor (other than on RDP)
-        _glfw.win32.blankCursor = CreateCursor(NULL, 0, 0, cursorWidth, cursorHeight, andMask, xorMask);
-
-        _glfw_free(andMask);
-        _glfw_free(xorMask);
-    }
-}
-
-// Initialize for remote sessions
-//
-static void initRemoteSession(void)
-{
-    //Check if the current progress was started with Remote Desktop.
-    _glfw.win32.isRemoteSession = GetSystemMetrics(SM_REMOTESESSION) > 0;
-
-    // With Remote desktop, we need to create a blank cursor because of the cursor is Set to NULL
-    // if cannot be moved to center in capture mode. If not Remote Desktop win32.blankCursor stays NULL
-    // and will perform has before (normal).
-    if (_glfw.win32.isRemoteSession)
-    {
-        createBlankCursor();
-    }
-}
-
 //////////////////////////////////////////////////////////////////////////
 //////                       GLFW internal API                      //////
 //////////////////////////////////////////////////////////////////////////
@@ -738,14 +698,8 @@ int _glfwInitWin32(void)
     if (!createHelperWindow())
         return GLFW_FALSE;
 
-    //Some hacks are needed to support Remote Desktop...
-    initRemoteSession();
-    if (_glfw.win32.isRemoteSession && _glfw.win32.blankCursor == NULL )
-    {
-        _glfwInputErrorWin32(GLFW_PLATFORM_ERROR,
-                             "Win32: Failed to create blank cursor for remote session.");
-        return GLFW_FALSE;
-    }
+    // Check if the current process was started via Remote Desktop
+    _glfw.win32.isRemoteSession = GetSystemMetrics(SM_REMOTESESSION) > 0;
 
     _glfwPollMonitorsWin32();
     return GLFW_TRUE;
@@ -754,7 +708,7 @@ int _glfwInitWin32(void)
 void _glfwTerminateWin32(void)
 {
     if (_glfw.win32.blankCursor)
-        DestroyCursor(_glfw.win32.blankCursor);
+        DestroyIcon((HICON) _glfw.win32.blankCursor);
 
     if (_glfw.win32.deviceNotificationHandle)
         UnregisterDeviceNotification(_glfw.win32.deviceNotificationHandle);
diff --git a/src/win32_window.c b/src/win32_window.c
index 6191f9a4..1a856713 100644
--- a/src/win32_window.c
+++ b/src/win32_window.c
@@ -1314,6 +1314,34 @@ static int createNativeWindow(_GLFWwindow* window,
         }
     }
 
+    if (_glfw.win32.isRemoteSession)
+    {
+        // NOTE: On Remote Desktop, setting the cursor to NULL does not hide it
+        // HACK: Create a transparent cursor and always set that instead of NULL
+        //       When not on Remote Desktop, this handle is NULL and normal hiding is used
+        if (!_glfw.win32.blankCursor)
+        {
+            const int cursorWidth = GetSystemMetrics(SM_CXCURSOR);
+            const int cursorHeight = GetSystemMetrics(SM_CYCURSOR);
+
+            unsigned char* cursorPixels = _glfw_calloc(cursorWidth * cursorHeight, 4);
+            if (!cursorPixels)
+                return GLFW_FALSE;
+
+            // NOTE: Windows checks whether the image is fully transparent and if so
+            //       just ignores the alpha channel and makes the whole cursor opaque
+            // HACK: Make one pixel slightly less transparent
+            cursorPixels[3] = 1;
+
+            const GLFWimage cursorImage = { cursorWidth, cursorHeight, cursorPixels };
+            _glfw.win32.blankCursor = createIcon(&cursorImage, 0, 0, FALSE);
+            _glfw_free(cursorPixels);
+
+            if (!_glfw.win32.blankCursor)
+                return GLFW_FALSE;
+        }
+    }
+
     if (window->monitor)
     {
         MONITORINFO mi = { sizeof(mi) };