Separate class for extension wrangler initialization.

src/Contexts/AbstractGlInterface.h

@@ -19,6 +19,8 @@
  * @brief Class Magnum::Contexts::AbstractGlInterface
  */
 
+#include "ExtensionWrangler.h"
+
 namespace Magnum { namespace Contexts {
 
 /** @brief Base for OpenGL interfaces */
@@ -41,6 +43,15 @@ template<class Display, class VisualId, class Window> class AbstractGlInterface
         /** @brief Create context */
         virtual void createContext(Window nativeWindow) = 0;
 
+        /**
+         * @brief Whether to enable experimental extension wrangler features
+         *
+         * Default is to disable.
+         */
+        virtual inline ExtensionWrangler::ExperimentalFeatures experimentalExtensionWranglerFeatures() const {
+            return ExtensionWrangler::ExperimentalFeatures::Disable;
+        }
+
         /** @brief Make the context current */
         virtual void makeCurrent() = 0;
 

src/Contexts/AbstractXContext.cpp

@@ -15,6 +15,8 @@
 
 #include "AbstractXContext.h"
 
+#include "ExtensionWrangler.h"
+
 #define None 0L // redef Xlib nonsense
 
 /* Mask for X events */
@@ -66,14 +68,8 @@ AbstractXContext::AbstractXContext(AbstractGlInterface<Display*, VisualID, Windo
     /* Set OpenGL context as current */
     glInterface->makeCurrent();
 
-    #ifndef MAGNUM_TARGET_GLES
+    /* Initialize extension wrangler */
-    /* Init GLEW */
+    ExtensionWrangler::initialize(glInterface->experimentalExtensionWranglerFeatures());
-    GLenum err = glewInit();
-    if(err != GLEW_OK) {
-        Error() << "AbstractXContext: cannot initialize GLEW:" << glewGetErrorString(err);
-        exit(1);
-    }
-    #endif
 }
 
 AbstractXContext::~AbstractXContext() {

src/Contexts/CMakeLists.txt

@@ -1,13 +1,19 @@
+# Extension wrangler
+add_library(MagnumContextsExtensionWrangler OBJECT ExtensionWrangler.cpp)
+
 set(MagnumContexts_HEADERS
     AbstractContext.h
-    AbstractGlInterface.h)
+    AbstractGlInterface.h
+    ExtensionWrangler.h)
 install(FILES ${MagnumContexts_HEADERS} DESTINATION ${MAGNUM_INCLUDE_INSTALL_DIR}/Contexts)
 
 # GLUT context
 if(WITH_GLUTCONTEXT)
     find_package(GLUT)
     if(GLUT_FOUND)
-        add_library(MagnumGlutContext STATIC GlutContext.cpp)
+        add_library(MagnumGlutContext STATIC
+            GlutContext.cpp
+            $<TARGET_OBJECTS:MagnumContextsExtensionWrangler>)
         install(FILES GlutContext.h DESTINATION ${MAGNUM_INCLUDE_INSTALL_DIR}/Contexts)
         install(TARGETS MagnumGlutContext DESTINATION ${MAGNUM_LIBRARY_INSTALL_DIR})
     else()
@@ -20,7 +26,9 @@ if(WITH_SDL2CONTEXT)
     find_package(SDL2)
     if(SDL2_FOUND)
         include_directories(${SDL2_INCLUDE_DIR})
-        add_library(MagnumSdl2Context STATIC Sdl2Context.cpp)
+        add_library(MagnumSdl2Context STATIC
+            Sdl2Context.cpp
+            $<TARGET_OBJECTS:MagnumContextsExtensionWrangler>)
         install(FILES Sdl2Context.h DESTINATION ${MAGNUM_INCLUDE_INSTALL_DIR}/Contexts)
         install(TARGETS MagnumSdl2Context DESTINATION ${MAGNUM_LIBRARY_INSTALL_DIR})
     else()
@@ -32,7 +40,10 @@ endif()
 if(WITH_XEGLCONTEXT)
     set(NEED_ABSTRACTXCONTEXT 1)
     set(NEED_EGLINTERFACE 1)
-    add_library(MagnumXEglContext STATIC $<TARGET_OBJECTS:MagnumAbstractXContext> $<TARGET_OBJECTS:MagnumEglInterface>)
+    add_library(MagnumXEglContext STATIC
+        $<TARGET_OBJECTS:MagnumAbstractXContext>
+        $<TARGET_OBJECTS:MagnumEglInterface>
+        $<TARGET_OBJECTS:MagnumContextsExtensionWrangler>)
     install(FILES XEglContext.h DESTINATION ${MAGNUM_INCLUDE_INSTALL_DIR}/Contexts)
     install(TARGETS MagnumXEglContext DESTINATION ${MAGNUM_LIBRARY_INSTALL_DIR})
 endif()

src/Contexts/ExtensionWrangler.cpp

@@ -0,0 +1,37 @@
+/*
+    Copyright © 2010, 2011, 2012 Vladimír Vondruš <mosra@centrum.cz>
+
+    This file is part of Magnum.
+
+    Magnum is free software: you can redistribute it and/or modify
+    it under the terms of the GNU Lesser General Public License version 3
+    only, as published by the Free Software Foundation.
+
+    Magnum is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+    GNU Lesser General Public License version 3 for more details.
+*/
+
+#include "ExtensionWrangler.h"
+
+#include "Magnum.h"
+
+namespace Magnum { namespace Contexts {
+
+void ExtensionWrangler::initialize(ExperimentalFeatures experimentalFeatures) {
+    #ifndef MAGNUM_TARGET_GLES
+    /* Enable experimental features */
+    if(experimentalFeatures == ExperimentalFeatures::Enable)
+        glewExperimental = true;
+
+    /* Init GLEW */
+    GLenum err = glewInit();
+    if(err != GLEW_OK) {
+        Error() << "ExtensionWrangler: cannot initialize GLEW:" << glewGetErrorString(err);
+        exit(1);
+    }
+    #endif
+}
+
+}}

src/Contexts/ExtensionWrangler.h

@@ -0,0 +1,39 @@
+#ifndef Magnum_Contexts_ExtensionWrangler_h
+#define Magnum_Contexts_ExtensionWrangler_h
+/*
+    Copyright © 2010, 2011, 2012 Vladimír Vondruš <mosra@centrum.cz>
+
+    This file is part of Magnum.
+
+    Magnum is free software: you can redistribute it and/or modify
+    it under the terms of the GNU Lesser General Public License version 3
+    only, as published by the Free Software Foundation.
+
+    Magnum is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+    GNU Lesser General Public License version 3 for more details.
+*/
+
+/** @file
+ * @brief Class Magnum::Contexts::ExtensionWrangler
+ */
+
+namespace Magnum { namespace Contexts {
+
+/** @brief Extension wrangler interface */
+class ExtensionWrangler {
+    public:
+        /** @brief Whether to enable or disable experimental features */
+        enum class ExperimentalFeatures {
+            Disable,
+            Enable
+        };
+
+        /** @brief Initialize extension wrangler */
+        static void initialize(ExperimentalFeatures experimentalFeatures = ExperimentalFeatures::Disable);
+};
+
+}}
+
+#endif

src/Contexts/GlutContext.cpp

@@ -15,6 +15,8 @@
 
 #include "GlutContext.h"
 
+#include "ExtensionWrangler.h"
+
 namespace Magnum { namespace Contexts {
 
 GlutContext* GlutContext::instance = nullptr;
@@ -35,12 +37,7 @@ GlutContext::GlutContext(int& argc, char** argv, const std::string& title, const
     glutMotionFunc(staticMouseMotionEvent);
     glutDisplayFunc(staticDrawEvent);
 
-    /* Init GLEW */
+    ExtensionWrangler::initialize();
-    GLenum err = glewInit();
-    if(err != GLEW_OK) {
-        Error() << "GlutContext: cannot initialize GLEW:" << glewGetErrorString(err);
-        exit(1);
-    }
 }
 
 }}

src/Contexts/Sdl2Context.cpp

@@ -14,6 +14,7 @@
 */
 
 #include "Sdl2Context.h"
+#include "ExtensionWrangler.h"
 
 namespace Magnum { namespace Contexts {
 
@@ -40,18 +41,9 @@ Sdl2Context::Sdl2Context(int, char**, const std::string& name, const Math::Vecto
 
     context = SDL_GL_CreateContext(window);
 
-    #ifndef MAGNUM_TARGET_GLES
     /* This must be enabled, otherwise (on my NVidia) it crashes when creating
        VAO. WTF. */
-    glewExperimental = true;
+    ExtensionWrangler::initialize(ExtensionWrangler::ExperimentalFeatures::Enable);
-
-    /* Init GLEW */
-    GLenum err = glewInit();
-    if(err != GLEW_OK) {
-        Error() << "Sdl2Context: cannot initialize GLEW:" << glewGetErrorString(err);
-        exit(1);
-    }
-    #endif
 
     /* Push resize event, so viewportEvent() is called at startup */
     SDL_Event* sizeEvent = new SDL_Event;