Use glLoadGen instead of GLEW.

Removed all known GLEW workarounds, added one small workaround for
missing ARB_texture_compression_bptc. I didn't want to patch glLoadGen
for just four enum values, this way it's possible to use stock one
without any patching (except for missing OpenGL 2.1 support, as stated
in external/OpenGL/GL/README.md).

As one file now replaces both `glew.h` and `glcorearb.h` and it has the
same size as `glcorearb.h` alone , it saves approximately 18k LOC,
resulting in 15 second shorter compilation time (5:03 before, 4:48 now).
Not bad.

CMakeLists.txt

@@ -92,9 +92,6 @@ elseif(TARGET_GLES2)
 else()
     find_package(OpenGLES3 REQUIRED)
 endif()
-if(NOT TARGET_GLES)
-    find_package(GLEW REQUIRED)
-endif()
 
 # Configuration variables (saved later to corradeConfigure.h)
 if(TARGET_GLES)

doc/building.dox

@@ -41,7 +41,6 @@ Minimal set of tools and libraries required for building is:
   >= 3.1. On Windows you can use **MinGW**, Visual Studio compiler still lacks
   some needed features.
 - **CMake** >= 2.8.8
-- **GLEW** - OpenGL extension wrangler (only if targeting desktop OpenGL)
 - **Corrade** - Plugin management and utility library. See
   @ref building-corrade "Corrade download and installation guide" for more
   information.
@@ -118,12 +117,6 @@ have installed them to MinGW directory, point to `CMAKE_FIND_ROOT_PATH` to
 MinGW installation prefix, e.g. specify `-DCMAKE_FIND_ROOT_PATH=C:/MinGW/`
 CMake parameter.
 
-If building fails with GLEW linking errors (`undefined reference to glew...`),
-you have to set `GLEW_LIBRARY_DLL` and `GLEW_LIBRARY_LIB` CMake variables
-manually. One of them should point to `glew32.dll` and the other to
-`glew32.lib`. CMake currently isn't able to distinguish between them and in
-most cases points both to the same location.
-
 See also Corrade's @ref building-corrade-windows-troubleshooting "troubleshooting section".
 
 @subsection building-features Enabling or disabling features
@@ -251,12 +244,11 @@ flags.
 this system there is also prepared `mingw32-magnum` development package in
 root, named `PKGBUILD-mingw32`.
 
-You will need MinGW32 versions of the compiler and all libraries (GLEW,
+You will need MinGW32 versions of the compiler and all dependent libraries
-Corrade), i.e. these ArchLinux packages:
+(Corrade), i.e. these ArchLinux packages:
 
 - `mingw32-gcc`, which depends on `mingw32-w32api` containing OpenGL headers
 - `mingw32-runtime`
-- `mingw32-glew`
 - `mingw32-corrade`
 
 Make sure you have `toolchains` submodule updated, as

doc/cmake.dox

@@ -47,7 +47,7 @@ variables:
 - `MAGNUM_PLUGINS_IMPORTER_DIR` -- Directory with importer plugins
 
 However, this command will try to find only the base library, not the optional
-components. The base library depends on %Corrade, OpenGL and GLEW libraries (or
+components. The base library depends on %Corrade and OpenGL libraries (or
 OpenGL ES libraries). Additional dependencies are specified by the components.
 The optional components are:
 

doc/getting-started.dox

@@ -58,7 +58,6 @@ CMake build system, see @ref cmake for more information.
 
     modules/FindCorrade.cmake
     modules/FindMagnum.cmake
-    modules/FindGLEW.cmake
     src/MyApplication.cpp
     src/CMakeLists.txt
     CMakeLists.txt

external/OpenGL/GL/CMakeLists.txt

@@ -22,4 +22,7 @@
 #   DEALINGS IN THE SOFTWARE.
 #
 
-install(FILES glcorearb.h DESTINATION ${MAGNUM_INCLUDE_INSTALL_DIR}/OpenGL/GL)
+add_library(MagnumGLLoadGenObjects OBJECT gl_magnum.c)
+set_target_properties(MagnumGLLoadGenObjects PROPERTIES COMPILE_FLAGS "${CMAKE_SHARED_LIBRARY_CXX_FLAGS}")
+
+install(FILES gl_magnum.h DESTINATION ${MAGNUM_INCLUDE_INSTALL_DIR}/OpenGL/GL)

modules/FindGLEW.cmake

@@ -1,67 +0,0 @@
-# Find GLEW - OpenGL Extension Wrangler handling module for CMake
-#
-# This module defines:
-#
-# GLEW_FOUND                - True if GLEW library is found
-# GLEW_LIBRARIES            - GLEW libraries
-# GLEW_INCLUDE_DIR          - Include dir
-#
-
-#
-#   This file is part of Magnum.
-#
-#   Copyright © 2010, 2011, 2012, 2013 Vladimír Vondruš <mosra@centrum.cz>
-#
-#   Permission is hereby granted, free of charge, to any person obtaining a
-#   copy of this software and associated documentation files (the "Software"),
-#   to deal in the Software without restriction, including without limitation
-#   the rights to use, copy, modify, merge, publish, distribute, sublicense,
-#   and/or sell copies of the Software, and to permit persons to whom the
-#   Software is furnished to do so, subject to the following conditions:
-#
-#   The above copyright notice and this permission notice shall be included
-#   in all copies or substantial portions of the Software.
-#
-#   THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
-#   IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-#   FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
-#   THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
-#   LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
-#   FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
-#   DEALINGS IN THE SOFTWARE.
-#
-
-# Include dir
-find_path(GLEW_INCLUDE_DIR
-    NAMES GL/glew.h)
-
-# Library
-if(NOT WIN32)
-    find_library(GLEW_LIBRARY GLEW)
-    set(GLEW_LIBRARIES_ GLEW_LIBRARY)
-    mark_as_advanced(GLEW_LIBRARY)
-else()
-    find_library(GLEW_LIBRARY_DLL glew32)
-    find_library(GLEW_LIBRARY_LIB glew32)
-    set(GLEW_LIBRARIES_ GLEW_LIBRARY_DLL GLEW_LIBRARY_LIB)
-    mark_as_advanced(GLEW_LIBRARY_DLL GLEW_LIBRARY_LIB)
-endif()
-
-include(FindPackageHandleStandardArgs)
-find_package_handle_standard_args("GLEW" DEFAULT_MSG
-    ${GLEW_LIBRARIES_}
-    GLEW_INCLUDE_DIR)
-
-if(NOT GLEW_FOUND)
-    return()
-endif()
-
-unset(GLEW_LIBRARIES_)
-
-if(NOT WIN32)
-    set(GLEW_LIBRARIES ${GLEW_LIBRARY})
-    mark_as_advanced(GLEW_LIBRARY)
-else()
-    set(GLEW_LIBRARIES ${GLEW_LIBRARY_DLL} ${GLEW_LIBRARY_LIB})
-    mark_as_advanced(GLEW_LIBRARY_DLL GLEW_LIBRARY_LIB)
-endif()

modules/FindMagnum.cmake

@@ -17,9 +17,9 @@
 #  MAGNUM_PLUGINS_IMPORTER_DIR  - Directory with importer plugins
 #  MAGNUM_PLUGINS_AUDIOIMPORTER_DIR - Directory with audio importer plugins
 # This command will try to find only the base library, not the optional
-# components. The base library depends on Corrade, OpenGL and GLEW
+# components. The base library depends on Corrade and OpenGL libraries (or
-# libraries. Additional dependencies are specified by the components. The
+# OpenGL ES libraries). Additional dependencies are specified by the
-# optional components are:
+# components. The optional components are:
 #  Audio            - Audio library (depends on OpenAL library)
 #  DebugTools       - DebugTools library (depends on MeshTools, Primitives,
 #                     SceneGraph, Shaders and Shapes components)
@@ -149,9 +149,6 @@ if(NOT MAGNUM_TARGET_GLES OR MAGNUM_TARGET_DESKTOP_GLES)
 else()
     find_package(OpenGLES2 REQUIRED)
 endif()
-if(NOT MAGNUM_TARGET_GLES)
-    find_package(GLEW REQUIRED)
-endif()
 
 # On Windows and in static builds, *Application libraries need to have
 # ${MAGNUM_LIBRARIES} listed in dependencies also after all other library names
@@ -334,9 +331,6 @@ if(NOT MAGNUM_TARGET_GLES OR MAGNUM_TARGET_DESKTOP_GLES)
 else()
     set(MAGNUM_LIBRARIES ${MAGNUM_LIBRARIES} ${OPENGLES2_LIBRARY})
 endif()
-if(NOT MAGNUM_TARGET_GLES)
-    set(MAGNUM_LIBRARIES ${MAGNUM_LIBRARIES} ${GLEW_LIBRARIES})
-endif()
 
 # Installation dirs
 include(CorradeLibSuffix)

src/CMakeLists.txt

@@ -165,7 +165,8 @@ set_target_properties(MagnumObjects PROPERTIES COMPILE_FLAGS "-DMagnumObjects_EX
 # Main library
 add_library(Magnum ${SHARED_OR_STATIC}
     $<TARGET_OBJECTS:MagnumObjects>
-    $<TARGET_OBJECTS:MagnumMathObjects>)
+    $<TARGET_OBJECTS:MagnumMathObjects>
+    $<TARGET_OBJECTS:MagnumGLLoadGenObjects>)
 if(BUILD_STATIC_PIC)
     # TODO: CMake 2.8.9 has this as POSITION_INDEPENDENT_CODE property
     set_target_properties(Magnum PROPERTIES COMPILE_FLAGS "${CMAKE_SHARED_LIBRARY_CXX_FLAGS}")
@@ -180,9 +181,6 @@ elseif(TARGET_GLES2)
 else()
     set(Magnum_LIBS ${Magnum_LIBS} ${OPENGLES3_LIBRARY})
 endif()
-if(NOT TARGET_GLES)
-    set(Magnum_LIBS ${Magnum_LIBS} ${GLEW_LIBRARIES})
-endif()
 target_link_libraries(Magnum ${Magnum_LIBS})
 
 install(TARGETS Magnum DESTINATION ${MAGNUM_LIBRARY_INSTALL_DIR})
@@ -238,7 +236,8 @@ if(BUILD_TESTS)
 
     add_library(MagnumTestLib ${SHARED_OR_STATIC}
         $<TARGET_OBJECTS:MagnumObjects>
-        $<TARGET_OBJECTS:MagnumMathObjects>)
+        $<TARGET_OBJECTS:MagnumMathObjects>
+        $<TARGET_OBJECTS:MagnumGLLoadGenObjects>)
     set_target_properties(MagnumTestLib PROPERTIES COMPILE_FLAGS -DCORRADE_GRACEFUL_ASSERT)
     target_link_libraries(MagnumTestLib ${Magnum_LIBS})
 

src/OpenGL.h

@@ -33,8 +33,7 @@
 
 /* Desktop OpenGL */
 #ifndef MAGNUM_TARGET_GLES
-#include <GL/glew.h>
+#include <OpenGL/GL/gl_magnum.h>
-#include <OpenGL/GL/glcorearb.h>
 
 /* NaCl has its own gl2.h, the official one causes linker issues. Additionaly
    to NaCl's gl2ext.h we are including our own to prevent undeclared symbol

src/Platform/AbstractContextHandler.h

@@ -28,8 +28,6 @@
  * @brief Class Magnum::Platform::AbstractContextHandler
  */
 
-#include "ExtensionWrangler.h"
-
 namespace Magnum { namespace Platform {
 
 /**
@@ -58,15 +56,6 @@ template<class Display, class VisualId, class Window> class AbstractContextHandl
         /** @brief Create context */
         virtual void createContext(Window nativeWindow) = 0;
 
-        /**
-         * @brief Whether to enable experimental extension wrangler features
-         *
-         * Default is to disable.
-         */
-        virtual ExtensionWrangler::ExperimentalFeatures experimentalExtensionWranglerFeatures() const {
-            return ExtensionWrangler::ExperimentalFeatures::Disable;
-        }
-
         /** @brief Make the context current */
         virtual void makeCurrent() = 0;
 

src/Platform/AbstractXApplication.cpp

@@ -97,7 +97,7 @@ void AbstractXApplication::createContext(const Configuration& configuration) {
     contextHandler->makeCurrent();
 
     /* Initialize extension wrangler */
-    ExtensionWrangler::initialize(contextHandler->experimentalExtensionWranglerFeatures());
+    ExtensionWrangler::initialize();
 
     c = new Context;
 }

src/Platform/ExtensionWrangler.cpp

@@ -32,20 +32,16 @@
 
 namespace Magnum { namespace Platform {
 
-void ExtensionWrangler::initialize(ExperimentalFeatures experimentalFeatures) {
+void ExtensionWrangler::initialize() {
     #ifndef MAGNUM_TARGET_GLES
-    /* Enable experimental features */
+    /* Init glLoadGen. Ignore functions that failed to load (described by
-    if(experimentalFeatures == ExperimentalFeatures::Enable)
+       `ogl_LOAD_SUCCEEDED + n` return code), as we requested the latest OpenGL
-        glewExperimental = true;
+       with many vendor extensions and there won't ever be a driver supporting
-
+       everything possible. */
-    /* Init GLEW */
+    if(ogl_LoadFunctions() == ogl_LOAD_FAILED) {
-    GLenum err = glewInit();
+        Error() << "ExtensionWrangler: cannot initialize glLoadGen";
-    if(err != GLEW_OK) {
-        Error() << "ExtensionWrangler: cannot initialize GLEW:" << glewGetErrorString(err);
         std::exit(1);
     }
-    #else
-    static_cast<void>(experimentalFeatures); /* Shut up about unused parameter */
     #endif
 }
 

src/Platform/ExtensionWrangler.h

@@ -35,14 +35,8 @@ class ExtensionWrangler {
     public:
         ExtensionWrangler() = delete;
 
-        /** @brief Whether to enable or disable experimental features */
-        enum class ExperimentalFeatures {
-            Disable,
-            Enable
-        };
-
         /** @brief Initialize extension wrangler */
-        static void initialize(ExperimentalFeatures experimentalFeatures = ExperimentalFeatures::Disable);
+        static void initialize();
 };
 
 }}

src/Platform/GlxContextHandler.h

@@ -55,11 +55,6 @@ class GlxContextHandler: public AbstractContextHandler<Display*, VisualID, Windo
         VisualID getVisualId(Display* nativeDisplay) override;
         void createContext(Window nativeWindow) override;
 
-        /* This must be enabled, otherwise (on my NVidia) it crashes when creating VAO. WTF. */
-        ExtensionWrangler::ExperimentalFeatures experimentalExtensionWranglerFeatures() const override {
-            return ExtensionWrangler::ExperimentalFeatures::Enable;
-        }
-
         void makeCurrent() override {
             glXMakeCurrent(display, window, context);
         }

src/Platform/Sdl2Application.cpp

@@ -106,9 +106,7 @@ bool Sdl2Application::tryCreateContext(const Configuration& configuration) {
         return false;
     }
 
-    /* This must be enabled, otherwise (on my NVidia) it crashes when creating
+    ExtensionWrangler::initialize();
-       VAO. WTF. */
-    ExtensionWrangler::initialize(ExtensionWrangler::ExperimentalFeatures::Enable);
 
     /* Push resize event, so viewportEvent() is called at startup */
     SDL_Event* sizeEvent = new SDL_Event;

src/Platform/WindowlessGlxApplication.cpp

@@ -28,6 +28,7 @@
 #include <Utility/Debug.h>
 
 #include "Context.h"
+#include "Platform/ExtensionWrangler.h"
 
 #define None 0L // redef Xlib nonsense
 
@@ -103,7 +104,7 @@ void WindowlessGlxApplication::createContext(const Configuration&) {
     }
 
     /* Initialize extension wrangler */
-    ExtensionWrangler::initialize(ExtensionWrangler::ExperimentalFeatures::Enable);
+    ExtensionWrangler::initialize();
 
     c = new Context;
 }

src/RenderbufferFormat.h

@@ -366,12 +366,8 @@ enum class RenderbufferFormat: GLenum {
     R11FG11FB10F = GL_R11F_G11F_B10F,
     #endif
 
-    /* 1.5.6 <= GLEW < 1.8.0 doesn't have this, even if there is
-       GL_ARB_ES2_compatibility */
-    #if defined(GL_RGB565) || defined(DOXYGEN_GENERATING_OUTPUT)
     /** RGB, normalized unsigned, red and blue 5bit, green 6bit. */
     RGB565 = GL_RGB565,
-    #endif
 
     /**
      * sRGBA, each component normalized unsigned byte.

src/TextureFormat.h

@@ -519,13 +519,7 @@ enum class TextureFormat: GLenum {
      * RGB, normalized unsigned, red and blue component 5bit, green 6bit.
      * @requires_gles30 %Extension @es_extension{OES,required_internalformat}
      */
-    /* 1.5.6 <= GLEW < 1.8.0 doesn't have this, even if there is
-       GL_ARB_ES2_compatibility */
-    #ifdef GL_RGB565
     RGB565 = GL_RGB565,
-    #else
-    RGB565 = 0x8D62,
-    #endif
 
     #ifndef MAGNUM_TARGET_GLES3
     /**
@@ -722,39 +716,37 @@ enum class TextureFormat: GLenum {
      */
     CompressedSignedRGRgtc2 = GL_COMPRESSED_SIGNED_RG_RGTC2,
 
-    /* These are named with _ARB suffix, because glcorearb.h doesn't
-       have suffixless version (?!) and GLEW has it without suffix as
-       late as of 1.8.0 { */
-
     /**
      * BPTC compressed RGB, unsigned float.
      * @requires_gl42 %Extension @extension{ARB,texture_compression_bptc}
      * @requires_gl BPTC texture compression is not available in OpenGL ES.
+     * @todo Remove workaround when glLoadGen has `GL_COMPRESSED_RGB_BPTC_UNSIGNED_FLOAT`
      */
-    CompressedRGBBptcUnsignedFloat = GL_COMPRESSED_RGB_BPTC_UNSIGNED_FLOAT_ARB,
+    CompressedRGBBptcUnsignedFloat = 0x8E8F,//GL_COMPRESSED_RGB_BPTC_UNSIGNED_FLOAT,
 
     /**
      * BPTC compressed RGB, signed float.
      * @requires_gl42 %Extension @extension{ARB,texture_compression_bptc}
      * @requires_gl BPTC texture compression is not available in OpenGL ES.
+     * @todo Remove workaround when glLoadGen has `GL_COMPRESSED_RGB_BPTC_SIGNED_FLOAT`
      */
-    CompressedRGBBptcSignedFloat = GL_COMPRESSED_RGB_BPTC_SIGNED_FLOAT_ARB,
+    CompressedRGBBptcSignedFloat = 0x8E8E,//GL_COMPRESSED_RGB_BPTC_SIGNED_FLOAT,
 
     /**
      * BPTC compressed RGBA, normalized unsigned.
      * @requires_gl42 %Extension @extension{ARB,texture_compression_bptc}
      * @requires_gl BPTC texture compression is not available in OpenGL ES.
+     * @todo Remove workaround when glLoadGen has `GL_COMPRESSED_RGBA_BPTC_UNORM`
      */
-    CompressedRGBABptcUnorm = GL_COMPRESSED_RGBA_BPTC_UNORM_ARB,
+    CompressedRGBABptcUnorm = 0x8E8C,//GL_COMPRESSED_RGBA_BPTC_UNORM,
 
     /**
      * BPTC compressed sRGBA, normalized unsigned.
      * @requires_gl42 %Extension @extension{ARB,texture_compression_bptc}
      * @requires_gl BPTC texture compression is not available in OpenGL ES.
+     * @todo Remove workaround when glLoadGen has `GL_COMPRESSED_SRGB_ALPHA_BPTC_UNORM`
      */
-    CompressedSRGBAlphaBptcUnorm = GL_COMPRESSED_SRGB_ALPHA_BPTC_UNORM_ARB,
+    CompressedSRGBAlphaBptcUnorm = 0x8E8D,//GL_COMPRESSED_SRGB_ALPHA_BPTC_UNORM,
-
-    /*}*/
     #endif
 
     /**