From ab6e48b8334fee855611ca00f7b6e1083778853e Mon Sep 17 00:00:00 2001
From: ocornut <omarcornut@gmail.com>
Date: Tue, 18 Oct 2022 12:17:59 +0200
Subject: [PATCH] Backends: GLFW: Perform a dummy glfwGetError() read to cancel
 missing mouse cursors errors. (#5785)

---
 backends/imgui_impl_glfw.cpp | 20 ++++++++++++++------
 docs/CHANGELOG.txt           |  1 +
 2 files changed, 15 insertions(+), 6 deletions(-)

diff --git a/backends/imgui_impl_glfw.cpp b/backends/imgui_impl_glfw.cpp
index ced233bb..6ed2e9e4 100644
--- a/backends/imgui_impl_glfw.cpp
+++ b/backends/imgui_impl_glfw.cpp
@@ -16,6 +16,7 @@
 
 // CHANGELOG
 // (minor and older changes stripped away, please see git history for details)
+//  2022-10-18: Perform a dummy glfwGetError() read to cancel missing mouse cursors errors. Using GLFW_VERSION_COMBINED directly. (#5785)
 //  2022-10-11: Using 'nullptr' instead of 'NULL' as per our switch to C++11.
 //  2022-09-26: Inputs: Renamed ImGuiKey_ModXXX introduced in 1.87 to ImGuiMod_XXX (old names still supported).
 //  2022-09-01: Inputs: Honor GLFW_CURSOR_DISABLED by not setting mouse position.
@@ -71,13 +72,16 @@
 #define GLFW_EXPOSE_NATIVE_WIN32
 #include <GLFW/glfw3native.h>   // for glfwGetWin32Window
 #endif
-#ifdef GLFW_RESIZE_NESW_CURSOR        // Let's be nice to people who pulled GLFW between 2019-04-16 (3.4 define) and 2019-11-29 (cursors defines) // FIXME: Remove when GLFW 3.4 is released?
-#define GLFW_HAS_NEW_CURSORS          (GLFW_VERSION_MAJOR * 1000 + GLFW_VERSION_MINOR * 100 >= 3400) // 3.4+ GLFW_RESIZE_ALL_CURSOR, GLFW_RESIZE_NESW_CURSOR, GLFW_RESIZE_NWSE_CURSOR, GLFW_NOT_ALLOWED_CURSOR
+
+// We gather version tests as define in order to easily see which features are version-dependent.
+#define GLFW_VERSION_COMBINED           (GLFW_VERSION_MAJOR * 1000 + GLFW_VERSION_MINOR * 100 + GLFW_VERSION_REVISION)
+#ifdef GLFW_RESIZE_NESW_CURSOR          // Let's be nice to people who pulled GLFW between 2019-04-16 (3.4 define) and 2019-11-29 (cursors defines) // FIXME: Remove when GLFW 3.4 is released?
+#define GLFW_HAS_NEW_CURSORS            (GLFW_VERSION_COMBINED >= 3400) // 3.4+ GLFW_RESIZE_ALL_CURSOR, GLFW_RESIZE_NESW_CURSOR, GLFW_RESIZE_NWSE_CURSOR, GLFW_NOT_ALLOWED_CURSOR
 #else
-#define GLFW_HAS_NEW_CURSORS          (0)
+#define GLFW_HAS_NEW_CURSORS            (0)
 #endif
-#define GLFW_HAS_GAMEPAD_API          (GLFW_VERSION_MAJOR * 1000 + GLFW_VERSION_MINOR * 100 >= 3300) // 3.3+ glfwGetGamepadState() new api
-#define GLFW_HAS_GET_KEY_NAME         (GLFW_VERSION_MAJOR * 1000 + GLFW_VERSION_MINOR * 100 >= 3200) // 3.2+ glfwGetKeyName()
+#define GLFW_HAS_GAMEPAD_API            (GLFW_VERSION_COMBINED >= 3300) // 3.3+ glfwGetGamepadState() new api
+#define GLFW_HAS_GETKEYNAME             (GLFW_VERSION_COMBINED >= 3200) // 3.2+ glfwGetKeyName()
 
 // GLFW data
 enum GlfwClientApi
@@ -293,7 +297,7 @@ void ImGui_ImplGlfw_ScrollCallback(GLFWwindow* window, double xoffset, double yo
 
 static int ImGui_ImplGlfw_TranslateUntranslatedKey(int key, int scancode)
 {
-#if GLFW_HAS_GET_KEY_NAME && !defined(__EMSCRIPTEN__)
+#if GLFW_HAS_GETKEYNAME && !defined(__EMSCRIPTEN__)
     // GLFW 3.1+ attempts to "untranslate" keys, which goes the opposite of what every other framework does, making using lettered shortcuts difficult.
     // (It had reasons to do so: namely GLFW is/was more likely to be used for WASD-type game controls rather than lettered shortcuts, but IHMO the 3.1 change could have been done differently)
     // See https://github.com/glfw/glfw/issues/1502 for details.
@@ -449,6 +453,7 @@ static bool ImGui_ImplGlfw_Init(GLFWwindow* window, bool install_callbacks, Glfw
 {
     ImGuiIO& io = ImGui::GetIO();
     IM_ASSERT(io.BackendPlatformUserData == nullptr && "Already initialized a platform backend!");
+    //printf("GLFW_VERSION: %d.%d.%d (%d)", GLFW_VERSION_MAJOR, GLFW_VERSION_MINOR, GLFW_VERSION_REVISION, GLFW_VERSION_COMBINED);
 
     // Setup backend capabilities flags
     ImGui_ImplGlfw_Data* bd = IM_NEW(ImGui_ImplGlfw_Data)();
@@ -489,6 +494,9 @@ static bool ImGui_ImplGlfw_Init(GLFWwindow* window, bool install_callbacks, Glfw
     bd->MouseCursors[ImGuiMouseCursor_ResizeNESW] = glfwCreateStandardCursor(GLFW_ARROW_CURSOR);
     bd->MouseCursors[ImGuiMouseCursor_ResizeNWSE] = glfwCreateStandardCursor(GLFW_ARROW_CURSOR);
     bd->MouseCursors[ImGuiMouseCursor_NotAllowed] = glfwCreateStandardCursor(GLFW_ARROW_CURSOR);
+#endif
+#if (GLFW_VERSION_COMBINED >= 3300) // Eat errors (see #5785)
+    (void)glfwGetError(NULL);
 #endif
     glfwSetErrorCallback(prev_error_callback);
 
diff --git a/docs/CHANGELOG.txt b/docs/CHANGELOG.txt
index 8fc86d99..708724fd 100644
--- a/docs/CHANGELOG.txt
+++ b/docs/CHANGELOG.txt
@@ -176,6 +176,7 @@ Other Changes:
 - Examples: Added all SDL examples to default VS solution.
 - Examples: Win32: Always use RegisterClassW() to ensure windows are Unicode. (#5725)
 - Backends: GLFW: Honor GLFW_CURSOR_DISABLED by not setting mouse position. (#5625) [@scorpion-26]
+- Backends: GLFW: Add glfwGetError() call on GLFW 3.3 to inhibit missing mouse cursor errors. (#5785) [@mitchellh]
 - Backends: SDL: Disable SDL 2.0.22 new "auto capture" which prevents drag and drop across windows
   (e.g. for multi-viewport support) and don't capture mouse when drag and dropping. (#5710)
 - Backends: Win32: Convert WM_CHAR values with MultiByteToWideChar() when window class was