From aa8bb4d64864e0c3cfb9374a367e783602b75eba Mon Sep 17 00:00:00 2001
From: Paolo Angelelli <paolo.angelelli@qt.io>
Date: Mon, 19 Aug 2019 21:12:09 +0200
Subject: Improve debugging in mapboxgl plugin when running without opengl
 backend

Change-Id: I252c163ad9296b52f14b83710fda0a469f882d73
Reviewed-by: Laszlo Agocs <laszlo.agocs@qt.io>
---
 src/plugins/geoservices/mapboxgl/qgeomapmapboxgl.cpp | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/src/plugins/geoservices/mapboxgl/qgeomapmapboxgl.cpp b/src/plugins/geoservices/mapboxgl/qgeomapmapboxgl.cpp
index ed36cd5f..b0967499 100644
--- a/src/plugins/geoservices/mapboxgl/qgeomapmapboxgl.cpp
+++ b/src/plugins/geoservices/mapboxgl/qgeomapmapboxgl.cpp
@@ -54,6 +54,7 @@
 #include <QtQuick/QQuickWindow>
 #include <QtQuick/QSGImageNode>
 #include <QtQuick/private/qsgtexture_p.h>
+#include <QtQuick/private/qsgcontext_p.h> // for debugging the context name
 
 #include <QMapboxGL>
 
@@ -101,6 +102,11 @@ QSGNode *QGeoMapMapboxGLPrivate::updateSceneGraph(QSGNode *node, QQuickWindow *w
         QOpenGLContext *currentCtx = QOpenGLContext::currentContext();
         if (!currentCtx) {
             qWarning("QOpenGLContext is NULL!");
+            qWarning() << "You are running on QSG backend " << QSGContext::backend();
+            qWarning("The MapboxGL plugin works with both Desktop and ES 2.0+ OpenGL versions.");
+            qWarning("Verify that your Qt is built with OpenGL, and what kind of OpenGL.");
+            qWarning("To force using a specific OpenGL version, check QSurfaceFormat::setRenderableType and QSurfaceFormat::setDefaultFormat");
+
             return node;
         }
         if (m_useFBO) {
-- 
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