From 58de77fc496cc978312dfdd1adfdc097f2c49850 Mon Sep 17 00:00:00 2001
From: MALET Jean-Luc <jlmxyz.forums@gmail.com>
Date: Sun, 28 Feb 2021 18:52:09 +0100
Subject: [PATCH] handle VisibilityNotify on x11 so that a window that is
 mapped but covered by another window is considered as not visible

---
 src/internal.h   |  1 +
 src/x11_window.c | 10 ++++++++--
 2 files changed, 9 insertions(+), 2 deletions(-)

diff --git a/src/internal.h b/src/internal.h
index f87c2f93..bfc25f44 100644
--- a/src/internal.h
+++ b/src/internal.h
@@ -383,6 +383,7 @@ struct _GLFWwindow
     GLFWbool            focusOnShow;
     GLFWbool            mousePassthrough;
     GLFWbool            shouldClose;
+    GLFWbool            visible;
     void*               userPointer;
     GLFWvidmode         videoMode;
     _GLFWmonitor*       monitor;
diff --git a/src/x11_window.c b/src/x11_window.c
index a85688e1..e04f1213 100644
--- a/src/x11_window.c
+++ b/src/x11_window.c
@@ -119,7 +119,7 @@ static GLFWbool waitForVisibilityNotify(_GLFWwindow* window)
         if (!waitForEvent(&timeout))
             return GLFW_FALSE;
     }
-
+    window->visible = GLFW_TRUE;
     return GLFW_TRUE;
 }
 
@@ -1838,6 +1838,12 @@ static void processEvent(XEvent *event)
             return;
         }
 
+        case VisibilityNotify :
+        {
+          if (event->xvisibility.state == VisibilityFullyObscured) window->visible = GLFW_FALSE;
+          else   window->visible = GLFW_TRUE;
+        }
+
         case DestroyNotify:
             return;
     }
@@ -2529,7 +2535,7 @@ int _glfwPlatformWindowVisible(_GLFWwindow* window)
 {
     XWindowAttributes wa;
     XGetWindowAttributes(_glfw.x11.display, window->x11.handle, &wa);
-    return wa.map_state == IsViewable;
+    return wa.map_state == IsViewable && window->visible == GLFW_TRUE;
 }
 
 int _glfwPlatformWindowMaximized(_GLFWwindow* window)