pism/src/main/java/org/toop/Window.java

package org.toop;

import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;
import org.lwjgl.*;
import org.lwjgl.glfw.*;
import org.lwjgl.opengl.*;
import org.lwjgl.system.*;

import java.nio.*;

import static org.lwjgl.glfw.Callbacks.*;
import static org.lwjgl.glfw.GLFW.*;
import static org.lwjgl.opengl.GL11.*;
import static org.lwjgl.system.MemoryStack.*;
import static org.lwjgl.system.MemoryUtil.*;
import static org.lwjgl.stb.STBImage.*;

public class Window extends Thread {

    private static final Logger logger = LogManager.getLogger(Main.class);
    // The window handle
    private long window;

    public void run() {

        init();
        loop();

        // Free the window callbacks and destroy the window
        glfwFreeCallbacks(window);
        glfwDestroyWindow(window);

        // Terminate GLFW and free the error callback
        glfwTerminate();
        glfwSetErrorCallback(null).free();
    }

    private void init() {
        // Set up an error callback. The default implementation
        // will print the error message in System.err.
        GLFWErrorCallback.createPrint(System.err).set();

        // Initialize GLFW. Most GLFW functions will not work before doing this.
        if ( !glfwInit() ){
            throw new IllegalStateException("Unable to initialize GLFW");
        }


        // Configure GLFW
        glfwDefaultWindowHints(); // optional, the current window hints are already the default
        glfwWindowHint(GLFW_VISIBLE, GLFW_FALSE); // the window will stay hidden after creation
        glfwWindowHint(GLFW_RESIZABLE, GLFW_TRUE); // the window will be resizable

        // Create the window
        window = glfwCreateWindow(1920, 1080, "ISY Game Selector", NULL, NULL);
        if ( window == NULL )
            throw new RuntimeException("Failed to create the GLFW window");

        // Set up a key callback. It will be called every time a key is pressed, repeated or released.
        glfwSetKeyCallback(window, (window, key, scancode, action, mods) -> {
            if ( key == GLFW_KEY_ESCAPE && action == GLFW_RELEASE ) {
                glfwSetWindowShouldClose(window, true); // We will detect this in the rendering loop
            }
        });

        // Get the thread stack and push a new frame
        try ( MemoryStack stack = stackPush() ) {
            IntBuffer pWidth = stack.mallocInt(1); // int*
            IntBuffer pHeight = stack.mallocInt(1); // int*

            // Get the window size passed to glfwCreateWindow
            glfwGetWindowSize(window, pWidth, pHeight);

            // Get the resolution of the primary monitor
            GLFWVidMode vidmode = glfwGetVideoMode(glfwGetPrimaryMonitor());

            // Center the window
            assert vidmode != null;
            glfwSetWindowPos(
                    window,
                    (vidmode.width() - pWidth.get(0)) / 2,
                    (vidmode.height() - pHeight.get(0)) / 2
            );



            // Prepare buffers to receive image data
            IntBuffer width  = stack.mallocInt(1);
            IntBuffer height = stack.mallocInt(1);
            IntBuffer channels = stack.mallocInt(1);

            // Load the image
            String imagePath = "img/icon.png";
            ByteBuffer image = stbi_load(imagePath, width, height, channels, 4); // Force RGBA (4 channels)

            if (image == null) {
                throw new RuntimeException("Failed to load image: " + stbi_failure_reason());
            }

            // Create GLFWImage
            GLFWImage icon = GLFWImage.malloc(stack);
            icon.set(width.get(0), height.get(0), image);

            // Create a buffer with the icon(s) — can be multiple icons for different sizes
            GLFWImage.Buffer icons = GLFWImage.malloc(1, stack);
            icons.put(0, icon);

            // Set the window icon
            glfwSetWindowIcon(window, icons);

            // Free the image data
            stbi_image_free(image);


        } // the stack frame is popped automatically

        // Make the OpenGL context current
        glfwMakeContextCurrent(window);
        // Enable v-sync
        glfwSwapInterval(1);

        // Make the window visible
        glfwShowWindow(window);
    }

    private void loop() {
        // This line is critical for LWJGL's interoperation with GLFW's
        // OpenGL context, or any context that is managed externally.
        // LWJGL detects the context that is current in the current thread,
        // creates the GLCapabilities instance and makes the OpenGL
        // bindings available for use.
        GL.createCapabilities();

        // Set the clear color
        glClearColor(0.5f, 0.5f, 0.5f, 0.0f);

        // Run the rendering loop until the user has attempted to close
        // the window or has pressed the ESCAPE key.
        while ( !glfwWindowShouldClose(window) ) {
            glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); // clear the framebuffer

            glfwSwapBuffers(window); // swap the color buffers

            // Poll for window events. The key callback above will only be
            // invoked during this call.
            glfwPollEvents();
        }
    }

    //public static void main(String[] args) {
        //new Window().run();
    //}
    /**
     * TODO: Is putting the window on a second thread, safe?
     * Can't overwrite start(), so a overload is needed.
     *
     * @param ignoredKeepEmpty Just input "" an empty string.
     */
    public static void start(String ignoredKeepEmpty){
        new Window().start();
    }

}