From e93bcd9e557e5176e3281b06cb83f53193864b37 Mon Sep 17 00:00:00 2001
From: Hajime Hoshi <hajimehoshi@gmail.com>
Date: Mon, 13 Mar 2023 21:40:25 +0900
Subject: [PATCH] internal/ui: bug fix: needed to wait for swapping buffers
 before entering fullscreen

Closes #2599
---
 internal/ui/ui_glfw.go | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/internal/ui/ui_glfw.go b/internal/ui/ui_glfw.go
index 2fcc7556c..20e6f120a 100644
--- a/internal/ui/ui_glfw.go
+++ b/internal/ui/ui_glfw.go
@@ -92,6 +92,8 @@ type userInterfaceImpl struct {
 	initWindowFloating       bool
 	initWindowMaximized      bool
 
+	bufferOnceSwapped bool
+
 	origWindowPosX        int
 	origWindowPosY        int
 	origWindowWidthInDIP  int
@@ -974,7 +976,8 @@ func (u *userInterfaceImpl) update() (float64, float64, error) {
 		return 0, 0, RegularTermination
 	}
 
-	if u.isInitFullscreen() {
+	// On macOS, one swapping buffers seems required before entering fullscreen (#2599).
+	if u.isInitFullscreen() && (u.bufferOnceSwapped || runtime.GOOS != "darwin") {
 		u.setFullscreen(true)
 		u.setInitFullscreen(false)
 	}
@@ -1067,6 +1070,8 @@ func (u *userInterfaceImpl) updateGame() error {
 
 		// This works only for OpenGL.
 		u.swapBuffersOnRenderThread()
+
+		u.bufferOnceSwapped = true
 	})
 
 	if unfocused {