No OpenGL context is current in the current thread

Question

I'm following a tutorial on youtube but I have a problem with OpenGL that I'm not able to solve. I have no idea how I can fix it.

Exception in thread "EndlessRunner" java.lang.IllegalStateException: No OpenGL context is current in the current thread.
at org.lwjgl.opengl.GLContextWindows.createFromCurrent(GLContextWindows.java:61)
at org.lwjgl.opengl.GLContext.createFromCurrent(GLContext.java:36)
at net.alfredo.Main.init(Main.java:59)
at net.alfredo.Main.run(Main.java:91)
at java.lang.Thread.run(Unknown Source)

Main

package net.alfredo;

import static org.lwjgl.glfw.GLFW.*;
import static org.lwjgl.opengl.GL11.*;
import static org.lwjgl.system.MemoryUtil.*;

import java.nio.ByteBuffer;

import org.lwjgl.glfw.GLFWKeyCallback;
import org.lwjgl.glfw.GLFWvidmode;
import org.lwjgl.opengl.GLContext;

import Input.Input;

public class Main implements Runnable {


private Thread thread;
public boolean running = true;

private GLFWKeyCallback keyCallback;

public Long window;

public static void main(String args[]) {

    Main game = new Main();
    game.start();

}

public void start(){

    running = true;
    thread = new Thread(this, "EndlessRunner");
    thread.start();

}

public void init(){

    if(glfwInit() != GL_TRUE){
        System.err.println("La inicializacion de GLWF fallo!");
    }

    glfwWindowHint(GLFW_RESIZABLE, GL_TRUE);

    window = glfwCreateWindow(800, 600, "Cuboid MMORPG", NULL, NULL);

    if(window == NULL){
        System.err.println("No se pudo crear la ventana!");
    }

    glfwSetKeyCallback(window, keyCallback = new Input());


    ByteBuffer vidmode = glfwGetVideoMode(glfwGetPrimaryMonitor());
    glfwSetWindowPos(window, 100, 100);

    glfwShowWindow(window);
    GLContext.createFromCurrent();

    glClearColor(0.56f  , 0.250f, 0.425f, 1.0f);

    glEnable(GL_DEPTH_TEST);

    System.out.println("OpenGL: " + glGetString(GL_VERSION));

}

public void update(){
    glfwPollEvents();

    if(Input.keys[GLFW_KEY_SPACE]){
        System.out.println("Has precionado la tecla Espacio!");

    }

}

public void render(){
    glfwSwapBuffers(window);

    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

}

@Override
public void run() {
    init();
    while(running){
        update();
        render();

        if (glfwWindowShouldClose(window) == GL_TRUE){

            running = false;

        }

    }

    keyCallback.release();

}
}

Answer 1

You need to call glfwMakeContextCurrent to bind the OpenGL context to your thread. There's a working example on the LWJGL website as well.

Answer 2

OpenGL contexts are bound to a thread when they are created, so they can only be used from that thread. See the answer here.