Fix crashes and incorrect extension queries on GL3+

glGetString(GL_EXTENSIONS) is deprecated in OpenGL 3.0+.
This means that in core profiles on 3.2+ (or without the fwd
compatibility bit on 3.0/3.1), the call is not supported and may
return NULL. This causes a crash in at least one place where we
try to blindly strstr the result. The correct solution is to use
QOpenGLContext::extensions() and hasExtension() which is prepared
to handle GL3+.

Change-Id: I52fec7dcee001cdc0933af03f5eed4b7c822b2bb
Reviewed-by: Shawn Rutledge <shawn.rutledge@digia.com>
Reviewed-by: Gunnar Sletta <gunnar.sletta@jollamobile.com>
Reviewed-by: Sean Harmer <sean.harmer@kdab.com>

1 files changed, 3 insertions, 3 deletions

diff --git a/src/quick/items/qquickshadereffectsource.cpp b/src/quick/items/qquickshadereffectsource.cpp
index 98203c51e5..f78a05ea9a 100644
--- a/src/quick/items/qquickshadereffectsource.cpp
+++ b/src/quick/items/qquickshadereffectsource.cpp
@@ -353,9 +353,9 @@ void QQuickShaderEffectTexture::grab()
             if (m_context->openglContext()->format().samples() <= 1) {
                 m_multisampling = false;
             } else {
-                QList<QByteArray> extensions = QByteArray((const char *)glGetString(GL_EXTENSIONS)).split(' ');
-                m_multisampling = extensions.contains("GL_EXT_framebuffer_multisample")
-                                && extensions.contains("GL_EXT_framebuffer_blit");
+                const QSet<QByteArray> extensions = m_context->openglContext()->extensions();
+                m_multisampling = extensions.contains(QByteArrayLiteral("GL_EXT_framebuffer_multisample"))
+                    && extensions.contains(QByteArrayLiteral("GL_EXT_framebuffer_blit"));
             }
             m_multisamplingChecked = true;
         }