allow custom opengl loader

include/render/GL.h

@@ -1,8 +1,62 @@
 #pragma once
 
-#ifdef __ANDROID__
-#include <GLES3/gl3.h>
+#if !defined(TD_IMPL_OPENGL_ES2) \
+ && !defined(TD_IMPL_OPENGL_ES3) \
+ && !defined(TD_IMPL_OPENGL_LOADER_GL3W) \
+ && !defined(TD_IMPL_OPENGL_LOADER_GLEW) \
+ && !defined(TD_IMPL_OPENGL_LOADER_GLAD) \
+ && !defined(TD_IMPL_OPENGL_LOADER_GLBINDING2) \
+ && !defined(TD_IMPL_OPENGL_LOADER_GLBINDING3) \
+ && !defined(TD_IMPL_OPENGL_LOADER_CUSTOM) \
+ && !defined(__ANDROID__)
+
+#if defined(__has_include)
+
+#if __has_include(<GL/glew.h>)
+    #define TD_IMPL_OPENGL_LOADER_GLEW
+#elif __has_include(<glad/glad.h>)
+    #define TD_IMPL_OPENGL_LOADER_GLAD
+#elif __has_include(<GL/gl3w.h>)
+    #define TD_IMPL_OPENGL_LOADER_GL3W
+#elif __has_include(<glbinding/glbinding.h>)
+    #define TD_IMPL_OPENGL_LOADER_GLBINDING3
+#elif __has_include(<glbinding/Binding.h>)
+    #define TD_IMPL_OPENGL_LOADER_GLBINDING2
 #else
-#include "glbinding/gl/gl.h"
-using namespace gl;
+    #error "Cannot detect OpenGL loader!"
+#endif
+
+#else
+	#error "Cannot detect loader with include detection !"
+#endif
+#endif
+
+
+
+// Include correct files
+
+#if defined(__ANDROID__)
+	#include <GLES3/gl3.h>
+#elif defined(TD_IMPL_OPENGL_LOADER_GL3W)
+	#include <GL/gl3w.h>            // Needs to be initialized with gl3wInit() in user's code
+#elif defined(TD_IMPL_OPENGL_LOADER_GLEW)
+	#include <GL/glew.h>            // Needs to be initialized with glewInit() in user's code.
+#elif defined(TD_IMPL_OPENGL_LOADER_GLAD)
+	#include <glad/glad.h>          // Needs to be initialized with gladLoadGL() in user's code.
+#elif defined(TD_IMPL_OPENGL_LOADER_GLBINDING2)
+	#ifndef GLFW_INCLUDE_NONE
+	#define GLFW_INCLUDE_NONE       // GLFW including OpenGL headers causes ambiguity or multiple definition errors.
+	#endif
+	#include <glbinding/Binding.h>  // Needs to be initialized with glbinding::Binding::initialize() in user's code.
+	#include <glbinding/gl/gl.h>
+	using namespace gl;
+#elif defined(TD_IMPL_OPENGL_LOADER_GLBINDING3)
+	#ifndef GLFW_INCLUDE_NONE
+	#define GLFW_INCLUDE_NONE       // GLFW including OpenGL headers causes ambiguity or multiple definition errors.
+	#endif
+	#include <glbinding/glbinding.h>// Needs to be initialized with glbinding::initialize() in user's code.
+	#include <glbinding/gl/gl.h>
+	using namespace gl;
+#else
+	#include TD_IMPL_OPENGL_LOADER_CUSTOM
 #endif

include/render/gui/imgui/imconfig.h

@@ -107,8 +107,20 @@ namespace ImGui
 }
 */
 
-#ifdef __ANDROID__
-#define IMGUI_IMPL_OPENGL_ES3
+#include "render/GL.h"
+
+#if defined(__ANDROID__)
+#define IMGUI_IMPL_OPENGL_LOADER_ES3
+#elif defined(TD_IMPL_OPENGL_LOADER_GL3W)
+    #define IMGUI_IMPL_OPENGL_LOADER_GL3W
+#elif defined(TD_IMPL_OPENGL_LOADER_GLEW)
+    #define IMGUI_IMPL_OPENGL_LOADER_GLEW
+#elif defined(TD_IMPL_OPENGL_LOADER_GLAD)
+    #define IMGUI_IMPL_OPENGL_LOADER_GLAD
+#elif defined(TD_IMPL_OPENGL_LOADER_GLBINDING2)
+    #define IMGUI_IMPL_OPENGL_LOADER_GLBINDING2
+#elif defined(TD_IMPL_OPENGL_LOADER_GLBINDING3)
+    #define IMGUI_IMPL_OPENGL_LOADER_GLBINDING3
 #else
-#define IMGUI_IMPL_OPENGL_LOADER_GLBINDING2
+    #define IMGUI_IMPL_OPENGL_LOADER_CUSTOM
 #endif

src/render/Renderer.cpp

@@ -5,9 +5,6 @@
  *      Author: simon
  */
 
-#ifndef ANDROID
-#include <glbinding/Binding.h>
-#endif
 #include "render/Renderer.h"
 #include "render/GL.h"
 #include <stdio.h>
@@ -43,7 +40,15 @@ void Renderer::InitShaders() {
 }
 
 bool Renderer::Init() {
-#ifndef ANDROID
+#if __has_include(<glbinding/glbinding.h>)
+    glbinding::initialize();
+#elif __has_include(<GL/glew.h>)
+	glewInit();
+#elif __has_include(<glad/glad.h>)
+	gladLoadGL();
+#elif __has_include(<GL/gl3w.h>)
+	gl3wInit();
+#elif __has_include(<glbinding/Binding.h>)
 	glbinding::Binding::initialize();
 #endif
     glEnable(GL_TEXTURE_2D);

xmake.lua

@@ -1,6 +1,12 @@
 add_rules("mode.debug", "mode.release")
 
---add_requires("SDL2", "glfw", "zlib", "glm")
+if is_os("linux") then
+    GL_LOADER = "glad"
+    add_defines("TD_IMPL_OPENGL_LOADER_GLAD");
+    add_requires("libsdl >= 2", "zlib", GL_LOADER)
+else
+    add_defines("TD_IMPL_OPENGL_LOADER_GLBINDING2");
+end
 
 target("TowerDefense")
     set_kind("binary")
@@ -8,15 +14,14 @@ target("TowerDefense")
     add_files("src/*.cpp", "src/*/*.cpp", "src/*/*/*.cpp", "src/*/*/*/*.cpp")
     add_cxflags("-pthread")
 
+    add_links("pthread")
+
     set_languages("c++17")
     
-    add_links("glbinding", "z", "SDL2")
-
-    if is_os("linux") then
-        add_links("GL", "pthread")
-    end
     if is_os("windows") then
-        add_links("opengl32", "ws2_32", "mingw32", "gdi32", "imm32")
+        add_links("opengl32", "ws2_32", "mingw32", "gdi32", "imm32", "z", "SDL2", "glbinding")
+    else
+        add_packages("zlib", "libsdl", GL_LOADER, "opengl")  
     end
     
     if is_mode("release") then