opengltestslo.c

1. Set `$PROJECT_DIR` as project directory
2. Download [GLFW Source package](https://github.com/glfw/glfw/releases/download/3.3.8/glfw-3.3.8.zip)
3. Extract `glfw-3.3.8.zip` folder to `$PROJECT_DIR`
4. `mkdir -p $PROJECT_DIR/glfw-3.3.8/build`
5. `cd $PROJECT_DIR/glfw-3.3.8/build`
6. `cmake ..`
7. `cmake --build .`
8. `mkdir -p $PROJECT_DIR/References/Include`
9. `mkdir -p $PROJECT_DIR/References/Libs`
10. `ln -s src/libglfw3.a $PROJECT_DIR/References/Libs/`
11. `ln -s ../include/GLFW $PROJECT_DIR/References/Include/`
12. `cd $PROJECT_DIR`
13. `mkdir -p GLAD`
14. Generate [GLAD](https://glad.dav1d.de/#language=c&specification=gl&api=gl%3D3.3&api=gles1%3Dnone&api=gles2%3Dnone&api=glsc2%3Dnone&profile=core&loader=on) and download `glad.zip`
15. Extract `glad.zip` to `$PROJECT_DIR/GLAD/`
16. `ln -s GLAD/include/glad References/Include/`
17. `ln -s GLAD/include/KHR References/Include/`
18. `mkdir -p HelloWindow/src/`
19. `cp GLAD/src/glac.c HelloWindow/src/`

```CMake
# $PROJECT_DIR/HelloWindow/CMakeLists.txt
cmake_minimum_required(VERSION 3.0)

project(HelloWindow)

file(GLOB_RECURSE sources src/*.c src/*.cpp src/*.h src/*.hpp)
add_executable(HelloWindow ${sources})

target_include_directories(HelloWindow PRIVATE ${CMAKE_SOURCE_DIR}/../References/Include)
target_link_libraries(HelloWindow
  ${CMAKE_SOURCE_DIR}/../References/Libs/libglfw3.a
  GL
  X11
  pthread
  Xrandr
  Xi
  dl
)
```
```cpp
// $PROJECT_DIR/HelloWindow/src/main.cpp
#include <glad/glad.h>
#include <GLFW/glfw3.h>

#include <iostream>

void framebuffer_size_callback(GLFWwindow *window, int width, int height)
{
  glViewport(0, 0, width, height);
}

void processInput(GLFWwindow *window)
{
  if (glfwGetKey(window, GLFW_KEY_ESCAPE) == GLFW_PRESS)
    glfwSetWindowShouldClose(window, true);
}

int main()
{
  glfwInit();
  glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
  glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
  glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);
  // glfwWindowHint(GLFW_OPENGL_FORWARD_COMPAT, GL_TRUE);

  GLFWwindow *window = glfwCreateWindow(800, 600, "LearnOpenGL", NULL, NULL);
  if (window == NULL)
  {
    std::cout << "Failed to create GLFW window" << std::endl;
    glfwTerminate();
    return -1;
  }
  glfwMakeContextCurrent(window);

  if (!gladLoadGLLoader((GLADloadproc)glfwGetProcAddress))
  {
    std::cout << "Failed to initialize GLAD" << std::endl;
    return -1;
  }

  glViewport(0, 0, 800, 600);

  glfwSetFramebufferSizeCallback(window, framebuffer_size_callback);

  while (!glfwWindowShouldClose(window))
  {
    processInput(window);

    glClearColor(0.2f, 0.3f, 0.3f, 1.0f);
    glClear(GL_COLOR_BUFFER_BIT);

    glfwSwapBuffers(window);
    glfwPollEvents();
  }

  glfwTerminate();
  return 0;
}
```
20. `mkdir -p HelloWindow/build`
21. `cd HelloWindow/build`
22. `cmake .. && cmake --build .`
23. `./HelloWindow`