use GLAD to link OpenGL

BUILDING-cmake.md

@@ -11,7 +11,6 @@ Required tools and dependencies:
 - CMake 3.21 or higher.
 - A working toolchain, e.g. Visual Studio on Windows or the `build-essentials` package on Ubuntu Linux.
 - Main OpenGL libraries and development files.
-- The `GLEW` Library on Windows.
 
 To use the library in other projects, it is required to install it. Use `CMAKE_INSTALL_PREFIX` to specify the
 installation directory.

BUILDING.md

@@ -100,11 +100,6 @@ development files. To build projectM, both binaries and development files need t
   library dependencies and/or using CMake to configure the build. Mainly used on Windows, but also works for Linux and
   macOS.
 
-### Only relevant for Windows:
-
-* [**GLEW**](http://glew.sourceforge.net/): The OpenGL Extension Wrangler Library. Only required if using CMake to
-  configure the build, the pre-created solutions use a bundled copy of GLEW.
-
 ## Building on Linux and macOS
 
 ### Installing dependencies

CMakeLists.txt

@@ -165,10 +165,6 @@ else()
 
     if(ENABLE_GLES)
         message(STATUS "Building for OpenGL Embedded Profile")
-        if(NOT CMAKE_SYSTEM_NAME STREQUAL Linux
-                AND NOT CMAKE_SYSTEM_NAME STREQUAL Android)
-            message(FATAL_ERROR "OpenGL ES 3 support is currently only available for Linux platforms. You're building for ${CMAKE_SYSTEM_NAME}.")
-        endif()
 
         # We use a local find script for OpenGL::GLES3 until the proposed changes are merged upstream.
         list(APPEND CMAKE_MODULE_PATH "${PROJECTM_SOURCE_DIR}/cmake/gles")
@@ -183,19 +179,6 @@ else()
         message(STATUS "Building for OpenGL Core Profile")
         find_package(OpenGL REQUIRED)
         set(PROJECTM_OPENGL_LIBRARIES OpenGL::GL)
-        # GLX is required by SOIL2 on platforms with the X Window System (e.g. most Linux distributions)
-        if(TARGET OpenGL::GLX)
-            list(APPEND PROJECTM_OPENGL_LIBRARIES OpenGL::GLX)
-        endif()
-        if(CMAKE_SYSTEM_NAME STREQUAL "Windows")
-            find_package(GLEW REQUIRED)
-            # Prefer shared, but check for static lib if shared is not available.
-            if(TARGET GLEW::glew)
-                list(APPEND PROJECTM_OPENGL_LIBRARIES GLEW::glew)
-            elseif(TARGET GLEW::glew_s)
-                list(APPEND PROJECTM_OPENGL_LIBRARIES GLEW::glew_s)
-            endif()
-        endif()
     endif()
 endif()
 

docs/building.rst

@@ -138,9 +138,6 @@ Only relevant for Windows:
    library dependencies and/or using CMake to configure the build.
 -  `NuGet <https://www.nuget.org/>`__: Dependency manager for .NET.
    Required to build the EyeTune app.
--  `GLEW <http://glew.sourceforge.net/>`__: The OpenGL Extension
-   Wrangler Library. Only required if using CMake to configure the
-   build, the pre-created solutions use a bundled copy of GLEW.
 
 Building on Linux and macOS
 ---------------------------

src/api/include/projectM-4/core.h

@@ -38,12 +38,31 @@ extern "C" {
  * If this function returns NULL, in most cases the OpenGL context is not initialized, not made
  * current or insufficient to render projectM visuals.
  *
+ * Note: The OpenGL resolver is initialized on the first invocation of either projectm_create() or projectm_create_with_opengl_load_proc().
+ *       All projectM instances created will use the same resolver.
+ *
  * @return A projectM handle for the newly created instance that must be used in subsequent API calls.
  *         NULL if the instance could not be created successfully.
  * @since 4.0.0
  */
 PROJECTM_EXPORT projectm_handle projectm_create();
 
+/**
+ * @brief Creates a new projectM instance using the given function to resolve GL api functions.
+ *
+ * The load_proc function accepts a function name and a user data pointer.
+ * If this function returns NULL, in most cases the OpenGL context is not initialized, not made
+ * current or insufficient to render projectM visuals.
+ *
+ * Note: The OpenGL resolver is initialized on the first invocation of either projectm_create() or projectm_create_with_opengl_load_proc().
+ *       All projectM instances created will use the same resolver and subsequent calls will ignore the given load_proc.
+ *
+ * @return A projectM handle for the newly created instance that must be used in subsequent API calls.
+ *         NULL if the instance could not be created successfully.
+ * @since 4.2.0
+ */
+PROJECTM_EXPORT projectm_handle projectm_create_with_opengl_load_proc(void* (*load_proc)(const char*, void*), void* user_data);
+
 /**
  * @brief Destroys the given instance and frees the resources.
  *

src/libprojectM/CMakeLists.txt

@@ -6,11 +6,21 @@ add_compile_definitions(
         $<IF:$<PLATFORM_ID:Windows>,STBI_NO_DDS,>
         )
 
+include_directories(
+        "${PROJECTM_SOURCE_DIR}/vendor/glad/include"
+        )
+
 add_subdirectory(Audio)
 add_subdirectory(MilkdropPreset)
 add_subdirectory(Renderer)
 add_subdirectory(UserSprites)
 
+set(PROJECTM_LINK_GL_LIBS "")
+if (WIN32)
+    # windows libs need to link to opengl32.dll
+    set(PROJECTM_LINK_GL_LIBS "${PROJECTM_OPENGL_LIBRARIES}")
+endif()
+
 add_library(projectM_main OBJECT
         "${PROJECTM_EXPORT_HEADER}"
         Logging.cpp
@@ -70,6 +80,7 @@ add_library(projectM
         $<TARGET_OBJECTS:SOIL2>
         $<TARGET_OBJECTS:projectM_main>
         $<TARGET_OBJECTS:projectM::Eval>
+        $<TARGET_OBJECTS:glad_obj>
         )
 
 target_include_directories(projectM
@@ -79,7 +90,7 @@ target_include_directories(projectM
 
 target_link_libraries(projectM
         PUBLIC
-        ${PROJECTM_OPENGL_LIBRARIES}
+        ${PROJECTM_LINK_GL_LIBS}
         libprojectM::API
         ${PROJECTM_FILESYSTEM_LIBRARY}
         )

src/libprojectM/MilkdropPreset/CMakeLists.txt

@@ -140,7 +140,6 @@ target_link_libraries(MilkdropPreset
         PUBLIC
         hlslparser
         GLM::GLM
-        ${PROJECTM_OPENGL_LIBRARIES}
         )
 
 if(NOT BUILD_SHARED_LIBS)

src/libprojectM/ProjectM.cpp

@@ -38,8 +38,8 @@
 
 namespace libprojectM {
 
-ProjectM::ProjectM()
-    : m_presetFactoryManager(std::make_unique<PresetFactoryManager>())
+ProjectM::ProjectM(const std::shared_ptr<Renderer::Platform::GLResolver>& glResolver)
+    : m_glResolver(glResolver), m_presetFactoryManager(std::make_unique<PresetFactoryManager>())
 {
     Initialize();
 }

src/libprojectM/ProjectM.hpp

@@ -39,6 +39,11 @@ class Renderer;
 class TextureManager;
 class ShaderCache;
 class TransitionShaderManager;
+
+namespace Platform {
+class GLResolver;
+}
+
 } // namespace Renderer
 
 namespace UserSprites {
@@ -52,7 +57,7 @@ class TimeKeeper;
 class PROJECTM_EXPORT ProjectM
 {
 public:
-    ProjectM();
+    ProjectM(const std::shared_ptr<Renderer::Platform::GLResolver>& glResolver);
 
     virtual ~ProjectM();
 
@@ -291,6 +296,7 @@ class PROJECTM_EXPORT ProjectM
     bool m_presetLocked{false};         //!< If true, the preset change event will not be sent.
     bool m_presetChangeNotified{false}; //!< Stores whether the user has been notified that projectM wants to switch the preset.
 
+    std::shared_ptr<Renderer::Platform::GLResolver> m_glResolver;                 //!< Function resolver for accessing GL backend.
     std::unique_ptr<PresetFactoryManager> m_presetFactoryManager; //!< Provides access to all available preset factories.
 
     Audio::PCM m_audioStorage;                                                    //!< Audio data buffer and analyzer instance.

src/libprojectM/ProjectMCWrapper.cpp

@@ -5,6 +5,7 @@
 #include <Logging.hpp>
 
 #include <Audio/AudioConstants.hpp>
+#include <Renderer/PlatformGLResolver.hpp>
 
 #include <projectM-4/parameters.h>
 #include <projectM-4/render_opengl.h>
@@ -14,6 +15,11 @@
 
 namespace libprojectM {
 
+projectMWrapper::projectMWrapper(const std::shared_ptr<Renderer::Platform::GLResolver>& glResolver)
+    : ProjectM(glResolver)
+{
+}
+
 void projectMWrapper::PresetSwitchRequestedEvent(bool isHardCut) const
 {
     if (m_presetSwitchRequestedEventCallback)
@@ -67,10 +73,27 @@ void projectm_free_string(const char* str)
 }
 
 projectm_handle projectm_create()
+{
+    return projectm_create_with_opengl_load_proc(nullptr, nullptr);
+}
+
+projectm_handle projectm_create_with_opengl_load_proc(void* (*load_proc)(const char*, void*), void* user_data)
 {
     try
     {
-        auto projectMInstance = new libprojectM::projectMWrapper();
+        // obtain shared resolver instance
+        auto glResolver = libprojectM::Renderer::Platform::GLResolver::Instance();
+
+        // init resolver to discover gl function pointers and init glad
+        // Initialize() is guarded internally, may be executed multiple times
+        auto success = glResolver->Initialize(load_proc, user_data);
+        if (!success)
+        {
+            return nullptr;
+        }
+
+        // create projectM
+        auto* projectMInstance = new libprojectM::projectMWrapper(glResolver);
         return reinterpret_cast<projectm_handle>(projectMInstance);
     }
     catch (...)

src/libprojectM/ProjectMCWrapper.hpp

@@ -30,6 +30,8 @@ namespace libprojectM {
 class projectMWrapper : public ProjectM
 {
 public:
+    projectMWrapper(const std::shared_ptr<Renderer::Platform::GLResolver>& glResolver);
+
     void PresetSwitchFailedEvent(const std::string& presetFilename,
                                  const std::string& failureMessage) const override;
     void PresetSwitchRequestedEvent(bool isHardCut) const override;

src/libprojectM/Renderer/CMakeLists.txt

@@ -32,6 +32,9 @@ add_library(Renderer OBJECT
         MilkdropNoise.cpp
         MilkdropNoise.hpp
         OpenGL.h
+        PlatformGLResolver.cpp
+        PlatformGLResolver.hpp
+        PlatformLoader.h
         Point.hpp
         PresetTransition.cpp
         PresetTransition.hpp
@@ -76,6 +79,8 @@ target_link_libraries(Renderer
         GLM::GLM
         hlslparser
         SOIL2
+        glad
+        ${PROJECTM_FILESYSTEM_LIBRARY}
         )
 
 set_target_properties(Renderer PROPERTIES

src/libprojectM/Renderer/OpenGL.h

@@ -4,31 +4,8 @@
  */
 #pragma once
 
-#ifdef __APPLE__ /* macOS */
-#include <OpenGL/gl3.h>
-#include <OpenGL/gl3ext.h>
-#elif defined(EYETUNE_WINRT) /* Universal Windows Platform */
-#define GL_GLEXT_PROTOTYPES
-#define GLM_FORCE_CXX03
-#include <EGL/egl.h>
-#include <EGL/eglext.h>
-#include <GLES2/gl2.h>
-#include <GLES2/gl2ext.h>
-#include <GLES3/gl3.h>
-#include <GLES3/gl31.h>
-#elif defined(_WIN32) /* Windows Desktop */
-#define GLM_FORCE_CXX03
-#include <GL/glew.h>
-#include <GL/wglew.h>
-#include <windows.h>
-#else /* Linux, BSD, Android, emscripten etc. */
 #ifdef USE_GLES
-#include <GLES3/gl3.h>
+   #include <glad/gles2.h>
 #else
-#if !defined(GL_GLEXT_PROTOTYPES)
-#define GL_GLEXT_PROTOTYPES
-#endif
-#include <GL/gl.h>
-#include <GL/glext.h>
-#endif
+   #include <glad/gl.h>
 #endif