furnace/extern/imgui_patched/backends/imgui_impl_opengl3.h

// 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 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: Large meshes support (64k+ vertices) with 16-bit indices (Desktop OpenGL only).
//  [X] Renderer: Multi-viewport support (multiple windows). Enable with 'io.ConfigFlags |= ImGuiConfigFlags_ViewportsEnable'.

// 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.
// Read online: https://github.com/ocornut/imgui/tree/master/docs

// About GLSL version:
//  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 = nullptr);
IMGUI_IMPL_API void     ImGui_ImplOpenGL3_Shutdown();
IMGUI_IMPL_API bool     ImGui_ImplOpenGL3_NewFrame();
IMGUI_IMPL_API void     ImGui_ImplOpenGL3_RenderDrawData(ImDrawData* draw_data);

// (Optional) Called by Init/NewFrame/Shutdown
IMGUI_IMPL_API bool     ImGui_ImplOpenGL3_CreateFontsTexture();
IMGUI_IMPL_API void     ImGui_ImplOpenGL3_DestroyFontsTexture();
IMGUI_IMPL_API bool     ImGui_ImplOpenGL3_CreateDeviceObjects();
IMGUI_IMPL_API void     ImGui_ImplOpenGL3_DestroyDeviceObjects();

// Specific OpenGL ES versions
//#define IMGUI_IMPL_OPENGL_ES2     // Auto-detected on Emscripten
//#define IMGUI_IMPL_OPENGL_ES3     // Auto-detected on iOS/Android

// 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)

// Try to detect GLES on matching platforms
#if defined(__APPLE__)
#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__) || defined(__amigaos4__)
#define IMGUI_IMPL_OPENGL_ES2               // Emscripten    -> GL ES 2, "#version 100"
#else
// Otherwise imgui_impl_opengl3_loader.h will be used.
#endif

#endif

#endif // #ifndef IMGUI_DISABLE