package main

import (
	"log"
	"runtime"

	"github.com/go-gl/gl/v3.3-core/gl"
	"github.com/go-gl/glfw/v3.3/glfw"
)

const (
	width  = 800
	height = 600
	title  = "Go OpenGL Example"
)

func init() {
	runtime.LockOSThread()
}

func main() {
	err := glfw.Init()
	if err != nil {
		log.Fatalln("Failed to initialize GLFW:", err)
	}
	defer glfw.Terminate()

	glfw.WindowHint(glfw.ContextVersionMajor, 3)
	glfw.WindowHint(glfw.ContextVersionMinor, 3)
	glfw.WindowHint(glfw.OpenGLProfile, glfw.OpenGLCoreProfile)
	glfw.WindowHint(glfw.OpenGLForwardCompatible, glfw.True)

	window, err := glfw.CreateWindow(width, height, title, nil, nil)
	if err != nil {
		log.Fatalln("Failed to create window:", err)
	}

	window.MakeContextCurrent()
	glfw.SwapInterval(1)

	if err := gl.Init(); err != nil {
		log.Fatalln("Failed to initialize OpenGL:", err)
	}

	gl.ClearColor(0.1, 0.1, 0.1, 1.0)

	for !window.ShouldClose() {
		gl.Clear(gl.COLOR_BUFFER_BIT)

		window.SwapBuffers()
		glfw.PollEvents()
	}
}