From f3bdb6cf0101693d48cd533a7bd381b3b3dbf8cc Mon Sep 17 00:00:00 2001
From: kirtijindal14 <kirti.jindal.ug23@nsut.ac.in>
Date: Thu, 30 Jul 2026 14:14:31 +0530
Subject: [PATCH] highgui: enable depth buffer for GTK3 GtkGLArea so
 GL_DEPTH_TEST works

---
 modules/highgui/src/window_gtk.cpp | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/modules/highgui/src/window_gtk.cpp b/modules/highgui/src/window_gtk.cpp
index ec5df72aa0..301013c542 100644
--- a/modules/highgui/src/window_gtk.cpp
+++ b/modules/highgui/src/window_gtk.cpp
@@ -1069,6 +1069,8 @@ static std::shared_ptr<CvWindow> namedWindow_(const std::string& name, int flags
 #if defined(HAVE_OPENGL) && defined(GTK_VERSION3)
     if (flags & cv::WINDOW_OPENGL) {
         window->glArea = gtk_gl_area_new();
+        // GtkGLArea has no depth buffer by default; request one so GL_DEPTH_TEST works.
+        gtk_gl_area_set_has_depth_buffer(GTK_GL_AREA(window->glArea), TRUE);
         gtk_container_add(GTK_CONTAINER(window->frame), window->glArea);
         gtk_widget_show(window->glArea);
     } else {