From c88ee0d0ad29ebf1ec85732489101c2bfffe2107 Mon Sep 17 00:00:00 2001
From: Hajime Hoshi <hajimehoshi@gmail.com>
Date: Sun, 18 Apr 2021 21:23:59 +0900
Subject: [PATCH] internal/uidriver/glfw: Bug fix: Unregister SetSize callback
 when undecorate the window

Closes #1586
---
 internal/uidriver/glfw/ui.go     | 17 +++++++++++++++++
 internal/uidriver/glfw/window.go |  8 ++------
 2 files changed, 19 insertions(+), 6 deletions(-)

diff --git a/internal/uidriver/glfw/ui.go b/internal/uidriver/glfw/ui.go
index e013ed3e4..fb80f0565 100644
--- a/internal/uidriver/glfw/ui.go
+++ b/internal/uidriver/glfw/ui.go
@@ -1362,3 +1362,20 @@ func (u *UserInterface) restore() {
 	w, h := u.window.GetSize()
 	u.setWindowSize(w, h, u.isFullscreen())
 }
+
+func (u *UserInterface) setDecorated(decorated bool) {
+	// SetAttrib with glfw.Decorated invokes the SetSize callback but the callback must not be called in the game's Update (#1586).
+	// SetSize callback is invoked in the limited situations like just after restoring from the fullscreen mode.
+	if u.unregisterWindowSetSizeCallback() {
+		defer u.registerWindowSetSizeCallback()
+	}
+	v := glfw.False
+	if decorated {
+		v = glfw.True
+	}
+	u.window.SetAttrib(glfw.Decorated, v)
+
+	// Just after restoring from the fullscreen mode, the window's size might be a wrong value on Windows.
+	// This was the cause to invoke SetSize callback unexpectedly. This sounds like a GLFW's issue, but this is not confirmed.
+	// As the window size should not be changed, setWindowSize doesn't have to be called anyway.
+}
diff --git a/internal/uidriver/glfw/window.go b/internal/uidriver/glfw/window.go
index 8a3c5d8eb..3b7c49890 100644
--- a/internal/uidriver/glfw/window.go
+++ b/internal/uidriver/glfw/window.go
@@ -51,14 +51,10 @@ func (w *window) SetDecorated(decorated bool) {
 			return nil
 		}
 
-		v := glfw.False
-		if decorated {
-			v = glfw.True
-		}
-		w.ui.window.SetAttrib(glfw.Decorated, v)
+		w.ui.setDecorated(decorated)
 
 		// The title can be lost when the decoration is gone. Recover this.
-		if v == glfw.True {
+		if decorated {
 			w.ui.window.SetTitle(w.ui.title)
 		}
 		return nil