#5609: When realising the render system in the constructor, give the …

…code a chance to invoke extensionsInitialised() first.

The extensionsInitialised() call will query the GL setup for the ability to use GL programs, which should preferably be known before we realise the OpenGLShader objects.

radiantcore/rendersystem/OpenGLRenderSystem.cpp

@@ -47,6 +47,8 @@ OpenGLRenderSystem::OpenGLRenderSystem() :
     _time(0),
     m_traverseRenderablesMutex(false)
 {
+    bool shouldRealise = false;
+
     // For the static default rendersystem, the MaterialManager is not existent yet,
     // hence it will be attached in initialiseModule().
     if (module::GlobalModuleRegistry().moduleExists(MODULE_SHADERSYSTEM))
@@ -58,17 +60,24 @@ OpenGLRenderSystem::OpenGLRenderSystem() :
 
         if (GlobalMaterialManager().isRealised())
         {
-            realise();
+            // Hold back with the realise() call until we know whether we can call 
+            // extensionsInitialised() below - this should happen before realise()
+            shouldRealise = true;
         }
     }
 
     // If the openGL module is already initialised and a shared context is created
     // trigger a call to extensionsInitialised().
-    if (GlobalRadiantCore().getModuleRegistry().moduleExists(MODULE_SHARED_GL_CONTEXT) &&
+    if (module::GlobalModuleRegistry().moduleExists(MODULE_SHARED_GL_CONTEXT) &&
         GlobalOpenGLContext().getSharedContext())
     {
         extensionsInitialised();
     }
+
+    if (shouldRealise)
+    {
+        realise();
+    }
 }
 
 OpenGLRenderSystem::~OpenGLRenderSystem()