Examples: OpenGL: Comments about versions and loaders. (#2393, #2351)

examples/README.txt

@@ -111,8 +111,8 @@ List of Renderer Bindings in this repository:
     imgui_impl_dx11.cpp       ; DirectX11
     imgui_impl_dx12.cpp       ; DirectX12
     imgui_impl_metal.mm       ; Metal (with ObjC)
-    imgui_impl_opengl2.cpp    ; OpenGL2 (legacy, fixed pipeline <- don't use with modern OpenGL context)
-    imgui_impl_opengl3.cpp    ; OpenGL3, OpenGL ES 2, OpenGL ES 3 (modern programmable pipeline)
+    imgui_impl_opengl2.cpp    ; OpenGL 2 (legacy, fixed pipeline <- don't use with modern OpenGL context)
+    imgui_impl_opengl3.cpp    ; OpenGL 3/4, OpenGL ES 2, OpenGL ES 3 (modern programmable pipeline)
     imgui_impl_vulkan.cpp     ; Vulkan
 
 List of high-level Frameworks Bindings in this repository: (combine Platform + Renderer)

examples/imgui_impl_opengl3.cpp

@@ -1,6 +1,7 @@
-// dear imgui: Renderer for OpenGL3 / OpenGL ES2 / OpenGL ES3 (modern OpenGL with shaders / programmatic pipeline)
+// dear imgui: Renderer for modern OpenGL with shaders / programmatic pipeline
+// - Desktop GL: 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..)
-// (Note: We are using GL3W as a helper library to access OpenGL functions since there is no standard header to access modern OpenGL functions easily. Alternatives are GLEW, Glad, etc..)
 
 // Implemented features:
 //  [X] Renderer: User texture binding. Use 'GLuint' OpenGL texture identifier as void*/ImTextureID. Read the FAQ about ImTextureID in imgui.cpp.
@@ -39,17 +40,17 @@
 // version   version   string
 //----------------------------------------
 //  2.0       110       "#version 110"
-//  2.1       120
-//  3.0       130
-//  3.1       140
+//  2.1       110       "#version 120"
+//  3.0       130       "#version 130"
+//  3.1       140       "#version 140"
 //  3.2       150       "#version 150"
-//  3.3       330
-//  4.0       400
+//  3.3       330       "#version 330 core"
+//  4.0       400       "#version 400 core"
 //  4.1       410       "#version 410 core"
-//  4.2       420
-//  4.3       430
-//  ES 2.0    100       "#version 100"
-//  ES 3.0    300       "#version 300 es"
+//  4.2       420       "#version 410 core"
+//  4.3       430       "#version 430 core"
+//  ES 2.0    100       "#version 100"      = WebGL 1.0
+//  ES 3.0    300       "#version 300 es"   = WebGL 2.0
 //----------------------------------------
 
 #if defined(_MSC_VER) && !defined(_CRT_SECURE_NO_WARNINGS)
@@ -78,10 +79,10 @@
 // OpenGL ES 3
 #include <GLES3/gl3.h>  // Use GL ES 3
 #else
-// Regular OpenGL
-// About OpenGL function loaders: modern OpenGL doesn't have a standard header file and requires individual function pointers to be loaded manually.
-// 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.
+// 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.
 #if defined(IMGUI_IMPL_OPENGL_LOADER_GL3W)
 #include <GL/gl3w.h>
 #elif defined(IMGUI_IMPL_OPENGL_LOADER_GLEW)

examples/imgui_impl_opengl3.h

@@ -1,6 +1,7 @@
-// dear imgui: Renderer for OpenGL3 / OpenGL ES2 / OpenGL ES3 (modern OpenGL with shaders / programmatic pipeline)
+// dear imgui: Renderer for modern OpenGL with shaders / programmatic pipeline
+// - Desktop GL: 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..)
-// (Note: We are using GL3W as a helper library to access OpenGL functions since there is no standard header to access modern OpenGL functions easily. Alternatives are GLEW, Glad, etc..)
 
 // Implemented features:
 //  [X] Renderer: User texture binding. Use 'GLuint' OpenGL texture identifier as void*/ImTextureID. Read the FAQ about ImTextureID in imgui.cpp.
@@ -9,19 +10,19 @@
 // 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 OpenGL function loaders:
-// About OpenGL function loaders: modern OpenGL doesn't have a standard header file and requires individual function pointers to be loaded manually.
-// 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.
+// 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.
 
 // About GLSL version:
-// The 'glsl_version' initialization parameter should be NULL (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.
+//  The 'glsl_version' initialization parameter should be NULL (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
 
-// Set default OpenGL loader to be gl3w
+// Set default OpenGL3 loader to be gl3w
 #if !defined(IMGUI_IMPL_OPENGL_LOADER_GL3W)     \
  && !defined(IMGUI_IMPL_OPENGL_LOADER_GLEW)     \
  && !defined(IMGUI_IMPL_OPENGL_LOADER_GLAD)     \