From 3ddcb3706fa3db7a302395255720b11f48883efc Mon Sep 17 00:00:00 2001
From: Uwe Rathmann <Uwe.Rathmann@tigertal.de>
Date: Tue, 6 Feb 2018 07:51:33 +0100
Subject: [PATCH] check for invalid contexts added

---
 src/nodes/QskTextureNode.cpp | 13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)

diff --git a/src/nodes/QskTextureNode.cpp b/src/nodes/QskTextureNode.cpp
index ae553935..5a7f8b31 100644
--- a/src/nodes/QskTextureNode.cpp
+++ b/src/nodes/QskTextureNode.cpp
@@ -177,10 +177,17 @@ QskTextureNode::~QskTextureNode()
 
     if ( d->material.textureId() > 0 )
     {
-        GLuint id = d->material.textureId();
+        /*
+            In certain environments we have the effect, that at
+            program termination the context is already gone
+         */
+        if ( auto context = QOpenGLContext::currentContext() )
+        {
+            GLuint id = d->material.textureId();
 
-        auto funcs = QOpenGLContext::currentContext()->functions();
-        funcs->glDeleteTextures( 1, &id );
+            auto funcs = context->functions();
+            funcs->glDeleteTextures( 1, &id );
+        }
     }
 }