Fix crash when using linuxfb and 2D rendererrelease-2.1.0

No longer should call any OpenGL functions on QML charts applications
if we don't have a valid OpenGL context.

Task-number: QTBUG-51387
Change-Id: Ic393f69921e300f19dc42c83fc07677ce7869273
Reviewed-by: Mika Salmela <mika.salmela@theqtcompany.com>
Reviewed-by: Miikka Heikkinen <miikka.heikkinen@theqtcompany.com>

2 files changed, 19 insertions, 17 deletions

diff --git a/src/chartsqml2/declarativechart.cpp b/src/chartsqml2/declarativechart.cpp
index ab0a612b..abff6836 100644
--- a/src/chartsqml2/declarativechart.cpp
+++ b/src/chartsqml2/declarativechart.cpp
@@ -512,14 +512,16 @@ QSGNode *DeclarativeChart::updatePaintNode(QSGNode *oldNode, QQuickItem::UpdateP
 
     if (!node) {
         node =  new DeclarativeChartNode(window());
-        connect(window(), &QQuickWindow::beforeRendering,
-                node->glRenderNode(), &DeclarativeRenderNode::render);
+        if (node->glRenderNode()) {
+            connect(window(), &QQuickWindow::beforeRendering,
+                    node->glRenderNode(), &DeclarativeRenderNode::render);
+        }
     }
 
     const QRectF &bRect = boundingRect();
 
     // Update GL data
-    if (m_glXYDataManager->dataMap().size() || m_glXYDataManager->mapDirty()) {
+    if (node->glRenderNode() && (m_glXYDataManager->dataMap().size() || m_glXYDataManager->mapDirty())) {
         const QRectF &plotArea = m_chart->plotArea();
         const QSizeF &chartAreaSize = m_chart->size();
 
diff --git a/src/chartsqml2/declarativechartnode.cpp b/src/chartsqml2/declarativechartnode.cpp
index 7b89c032..7d423b25 100644
--- a/src/chartsqml2/declarativechartnode.cpp
+++ b/src/chartsqml2/declarativechartnode.cpp
@@ -39,27 +39,27 @@ DeclarativeChartNode::DeclarativeChartNode(QQuickWindow *window) :
     m_textureSize(1, 1),
     m_glRenderNode(0)
 {
-    initializeOpenGLFunctions();
-
     // Our texture node must have a texture, so use a default one pixel texture
-    GLuint defaultTexture = 0;
-    glGenTextures(1, &defaultTexture);
-    glBindTexture(GL_TEXTURE_2D, defaultTexture);
-    uchar buf[4] = { 0, 0, 0, 0 };
-    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, 1, 1, 0, GL_RGBA, GL_UNSIGNED_BYTE, &buf);
-
+    QImage dummyImage(QSize(1, 1), QImage::Format_ARGB32);
+    uchar *imageData = dummyImage.bits();
+    imageData[0] = 0;
+    imageData[1] = 0;
+    imageData[2] = 0;
+    imageData[3] = 0;
     QQuickWindow::CreateTextureOptions defaultTextureOptions = QQuickWindow::CreateTextureOptions(
             QQuickWindow::TextureHasAlphaChannel | QQuickWindow::TextureOwnsGLTexture);
-    m_texture = m_window->createTextureFromId(defaultTexture, QSize(1, 1), defaultTextureOptions);
+    m_texture = m_window->createTextureFromImage(dummyImage, defaultTextureOptions);
 
     setTexture(m_texture);
     setFiltering(QSGTexture::Linear);
 
-    // Create child node for rendering GL graphics
-    m_glRenderNode = new DeclarativeRenderNode(m_window);
-    m_glRenderNode->setFlag(OwnedByParent);
-    appendChildNode(m_glRenderNode);
-    m_glRenderNode->setRect(0, 0, 0, 0); // Hide child node by default
+    if (QOpenGLContext::currentContext()) {
+        // Create child node for rendering GL graphics
+        m_glRenderNode = new DeclarativeRenderNode(m_window);
+        m_glRenderNode->setFlag(OwnedByParent);
+        appendChildNode(m_glRenderNode);
+        m_glRenderNode->setRect(0, 0, 0, 0); // Hide child node by default
+    }
 }
 
 DeclarativeChartNode::~DeclarativeChartNode()