Examples: Use imgui_impl_opengl3_loader.h instead of gl3w (thedmd#264)

Author: thedmd

docs/CHANGELOG.txt

@@ -4,6 +4,8 @@ v0.9.4 (WIP):
 
     BUGFIX: Editor: Don't duplicated ImVec2/ImVec3 == != operators defined since ImGui r19002 (#268)
 
+    BUGFIX: Examples: Use imgui_impl_opengl3_loader.h instead of gl3w (#264)
+
 v0.9.3 (2023-10-14):
 
     CHANGE: Canvas: Use ImDrawCallback_ImCanvas macro as draw callback sentinel (#256), thanks @nspitko

examples/application/CMakeLists.txt

@@ -69,15 +69,12 @@ endif()
 if (OpenGL_FOUND)
     set(HAVE_OPENGL YES)
 
-    find_package(gl3w REQUIRED)
-    # Explicitly select embedded GL3W loader
-    target_compile_definitions(application PRIVATE IMGUI_IMPL_OPENGL_LOADER_GL3W)
-
     target_include_directories(application PRIVATE ${OPENGL_INCLUDE_DIR})
-    target_link_libraries(application PRIVATE ${OPENGL_gl_LIBRARY} gl3w)
+    target_link_libraries(application PRIVATE ${OPENGL_gl_LIBRARY})
     list(APPEND _Application_Sources
         source/imgui_impl_opengl3.cpp
         source/imgui_impl_opengl3.h
+        source/imgui_impl_opengl3_loader.h
     )
 endif()
 

examples/application/source/imgui_impl_opengl3.cpp

@@ -1,31 +1,36 @@
-// dear imgui: Renderer for modern OpenGL with shaders / programmatic pipeline
+// dear imgui: Renderer Backend for modern OpenGL with shaders / programmatic pipeline
 // - Desktop GL: 2.x 3.x 4.x
 // - Embedded GL: ES 2.0 (WebGL 1.0), ES 3.0 (WebGL 2.0)
-// This needs to be used along with a Platform Binding (e.g. GLFW, SDL, Win32, custom..)
+// This needs to be used along with a Platform Backend (e.g. GLFW, SDL, Win32, custom..)
 
 // Implemented features:
 //  [X] Renderer: User texture binding. Use 'GLuint' OpenGL texture identifier as void*/ImTextureID. Read the FAQ about ImTextureID!
-//  [x] Renderer: Desktop GL only: Support for large meshes (64k+ vertices) with 16-bit indices.
+//  [x] Renderer: Large meshes support (64k+ vertices) with 16-bit indices (Desktop OpenGL only).
 
-// You can copy and use unmodified imgui_impl_* files in your project. See main.cpp for an example of using this.
-// If you are new to dear imgui, read examples/README.txt and read the documentation at the top of imgui.cpp.
-// https://github.com/ocornut/imgui
+// About WebGL/ES:
+// - You need to '#define IMGUI_IMPL_OPENGL_ES2' or '#define IMGUI_IMPL_OPENGL_ES3' to use WebGL or OpenGL ES.
+// - This is done automatically on iOS, Android and Emscripten targets.
+// - For other targets, the define needs to be visible from the imgui_impl_opengl3.cpp compilation unit. If unsure, define globally or in imconfig.h.
 
-// About Desktop OpenGL function loaders:
-//  Modern Desktop OpenGL doesn't have a standard portable header file to load OpenGL function pointers.
-//  Helper libraries are often used for this purpose! Here we are supporting a few common ones (gl3w, glew, glad).
-//  You may use another loader/header of your choice (glext, glLoadGen, etc.), or chose to manually implement your own.
+// You can use unmodified imgui_impl_* files in your project. See examples/ folder for examples of using this.
+// Prefer including the entire imgui/ repository into your project (either as a copy or as a submodule), and only build the backends you need.
+// Learn about Dear ImGui:
+// - FAQ                  https://dearimgui.com/faq
+// - Getting Started      https://dearimgui.com/getting-started
+// - Documentation        https://dearimgui.com/docs (same as your local docs/ folder).
+// - Introduction, links and more at the top of imgui.cpp
 
 // About GLSL version:
-//  The 'glsl_version' initialization parameter should be NULL (default) or a "#version XXX" string.
+//  The 'glsl_version' initialization parameter should be nullptr (default) or a "#version XXX" string.
 //  On computer platform the GLSL version default to "#version 130". On OpenGL ES 3 platform it defaults to "#version 300 es"
 //  Only override if your GL version doesn't handle this GLSL version. See GLSL version table at the top of imgui_impl_opengl3.cpp.
 
 #pragma once
 #include "imgui.h"      // IMGUI_IMPL_API
+#ifndef IMGUI_DISABLE
 
 // Backend API
-IMGUI_IMPL_API bool     ImGui_ImplOpenGL3_Init(const char* glsl_version = NULL);
+IMGUI_IMPL_API bool     ImGui_ImplOpenGL3_Init(const char* glsl_version = nullptr);
 IMGUI_IMPL_API void     ImGui_ImplOpenGL3_Shutdown();
 IMGUI_IMPL_API void     ImGui_ImplOpenGL3_NewFrame();
 IMGUI_IMPL_API void     ImGui_ImplOpenGL3_RenderDrawData(ImDrawData* draw_data);
@@ -40,48 +45,22 @@ IMGUI_IMPL_API void     ImGui_ImplOpenGL3_DestroyDeviceObjects();
 //#define IMGUI_IMPL_OPENGL_ES2     // Auto-detected on Emscripten
 //#define IMGUI_IMPL_OPENGL_ES3     // Auto-detected on iOS/Android
 
-// Attempt to auto-detect the default Desktop GL loader based on available header files.
-// If auto-detection fails or doesn't select the same GL loader file as used by your application,
-// you are likely to get a crash in ImGui_ImplOpenGL3_Init().
-// You can explicitly select a loader by using one of the '#define IMGUI_IMPL_OPENGL_LOADER_XXX' in imconfig.h or compiler command-line.
+// You can explicitly select GLES2 or GLES3 API by using one of the '#define IMGUI_IMPL_OPENGL_LOADER_XXX' in imconfig.h or compiler command-line.
 #if !defined(IMGUI_IMPL_OPENGL_ES2) \
- && !defined(IMGUI_IMPL_OPENGL_ES3) \
- && !defined(IMGUI_IMPL_OPENGL_LOADER_GL3W) \
- && !defined(IMGUI_IMPL_OPENGL_LOADER_GLEW) \
- && !defined(IMGUI_IMPL_OPENGL_LOADER_GLAD) \
- && !defined(IMGUI_IMPL_OPENGL_LOADER_GLAD2) \
- && !defined(IMGUI_IMPL_OPENGL_LOADER_GLBINDING2) \
- && !defined(IMGUI_IMPL_OPENGL_LOADER_GLBINDING3) \
- && !defined(IMGUI_IMPL_OPENGL_LOADER_CUSTOM)
+ && !defined(IMGUI_IMPL_OPENGL_ES3)
 
 // Try to detect GLES on matching platforms
 #if defined(__APPLE__)
-#include "TargetConditionals.h"
+#include <TargetConditionals.h>
 #endif
 #if (defined(__APPLE__) && (TARGET_OS_IOS || TARGET_OS_TV)) || (defined(__ANDROID__))
 #define IMGUI_IMPL_OPENGL_ES3               // iOS, Android  -> GL ES 3, "#version 300 es"
-#elif defined(__EMSCRIPTEN__)
+#elif defined(__EMSCRIPTEN__) || defined(__amigaos4__)
 #define IMGUI_IMPL_OPENGL_ES2               // Emscripten    -> GL ES 2, "#version 100"
-
-// Otherwise try to detect supported Desktop OpenGL loaders..
-#elif defined(__has_include)
-#if __has_include(<GL/glew.h>)
-    #define IMGUI_IMPL_OPENGL_LOADER_GLEW
-#elif __has_include(<glad/glad.h>)
-    #define IMGUI_IMPL_OPENGL_LOADER_GLAD
-#elif __has_include(<glad/gl.h>)
-    #define IMGUI_IMPL_OPENGL_LOADER_GLAD2
-#elif __has_include(<GL/gl3w.h>)
-    #define IMGUI_IMPL_OPENGL_LOADER_GL3W
-#elif __has_include(<glbinding/glbinding.h>)
-    #define IMGUI_IMPL_OPENGL_LOADER_GLBINDING3
-#elif __has_include(<glbinding/Binding.h>)
-    #define IMGUI_IMPL_OPENGL_LOADER_GLBINDING2
-#else
-    #error "Cannot detect OpenGL loader!"
-#endif
 #else
-    #define IMGUI_IMPL_OPENGL_LOADER_GL3W   // Default to GL3W embedded in our repository
+// Otherwise imgui_impl_opengl3_loader.h will be used.
 #endif
 
 #endif
+
+#endif // #ifndef IMGUI_DISABLE