Backends: OpenGL3: Added more explicit comments about using GL ES2/3 on targets where it's not automatic. (#6450)

backends/imgui_impl_opengl3.cpp

@@ -7,6 +7,11 @@
 //  [X] Renderer: User texture binding. Use 'GLuint' OpenGL texture identifier as void*/ImTextureID. Read the FAQ about ImTextureID!
 //  [x] Renderer: Large meshes support (64k+ vertices) with 16-bit indices (Desktop OpenGL only).
 
+// 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.
+
 // 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.
 // If you are new to Dear ImGui, read documentation from the docs/ folder + read the top of imgui.cpp.

backends/imgui_impl_opengl3.h

@@ -7,6 +7,11 @@
 //  [X] Renderer: User texture binding. Use 'GLuint' OpenGL texture identifier as void*/ImTextureID. Read the FAQ about ImTextureID!
 //  [x] Renderer: Large meshes support (64k+ vertices) with 16-bit indices (Desktop OpenGL only).
 
+// 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.
+
 // 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.
 // If you are new to Dear ImGui, read documentation from the docs/ folder + read the top of imgui.cpp.