Tutorials.Tutorial1.java Source code

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Here is the source code for Tutorials.Tutorial1.java

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package Tutorials;

import java.nio.ByteBuffer;
import org.lwjgl.Sys;
import static org.lwjgl.glfw.Callbacks.errorCallbackPrint;
import static org.lwjgl.glfw.GLFW.GLFW_KEY_ESCAPE;
import static org.lwjgl.glfw.GLFW.GLFW_RELEASE;
import static org.lwjgl.glfw.GLFW.GLFW_RESIZABLE;
import static org.lwjgl.glfw.GLFW.GLFW_VISIBLE;
import static org.lwjgl.glfw.GLFW.glfwCreateWindow;
import static org.lwjgl.glfw.GLFW.glfwDefaultWindowHints;
import static org.lwjgl.glfw.GLFW.glfwDestroyWindow;
import static org.lwjgl.glfw.GLFW.glfwGetPrimaryMonitor;
import static org.lwjgl.glfw.GLFW.glfwGetVideoMode;
import static org.lwjgl.glfw.GLFW.glfwInit;
import static org.lwjgl.glfw.GLFW.glfwMakeContextCurrent;
import static org.lwjgl.glfw.GLFW.glfwPollEvents;
import static org.lwjgl.glfw.GLFW.glfwSetErrorCallback;
import static org.lwjgl.glfw.GLFW.glfwSetKeyCallback;
import static org.lwjgl.glfw.GLFW.glfwSetWindowPos;
import static org.lwjgl.glfw.GLFW.glfwSetWindowShouldClose;
import static org.lwjgl.glfw.GLFW.glfwShowWindow;
import static org.lwjgl.glfw.GLFW.glfwSwapBuffers;
import static org.lwjgl.glfw.GLFW.glfwSwapInterval;
import static org.lwjgl.glfw.GLFW.glfwTerminate;
import static org.lwjgl.glfw.GLFW.glfwWindowHint;
import static org.lwjgl.glfw.GLFW.glfwWindowShouldClose;
import org.lwjgl.glfw.GLFWErrorCallback;
import org.lwjgl.glfw.GLFWKeyCallback;
import org.lwjgl.glfw.GLFWvidmode;
import org.lwjgl.opengl.GL11;
import static org.lwjgl.opengl.GL11.*;
import static org.lwjgl.opengl.GL11.glBegin;
import static org.lwjgl.opengl.GL11.glClear;
import static org.lwjgl.opengl.GL11.glClearColor;
import static org.lwjgl.opengl.GL11.glColor3f;
import static org.lwjgl.opengl.GL11.glEnd;
import static org.lwjgl.opengl.GL11.glVertex3f;
import org.lwjgl.opengl.GLContext;
import static org.lwjgl.system.MemoryUtil.NULL;

/**
 *
 * @author Agustin
 */
public class Tutorial1 {

    // We need to strongly reference callback instances.
    private GLFWErrorCallback errorCallback;
    private GLFWKeyCallback keyCallback;

    // The window handle
    private long window;

    public void run() {
        System.out.println("Hello LWJGL " + Sys.getVersion() + "!. Tutorial 1");

        try {
            initGL();
            loop();

            // Release window and window callbacks
            glfwDestroyWindow(window);
            keyCallback.release();
        } finally {
            // Terminate GLFW and release the GLFWerrorfun
            glfwTerminate();
            errorCallback.release();
        }
    }

    private void initGL() {
        // Setup an error callback. The default implementation
        // will print the error message in System.err.
        glfwSetErrorCallback(errorCallback = errorCallbackPrint(System.err));

        // Initialize GLFW. Most GLFW functions will not work before doing this.
        if (glfwInit() != GL11.GL_TRUE) {
            throw new IllegalStateException("Unable to initialize GLFW");
        }

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

        int WIDTH = 500;
        int HEIGHT = 500;

        // Create the window
        window = glfwCreateWindow(WIDTH, HEIGHT, "Tutorial 1", NULL, NULL);
        if (window == NULL) {
            throw new RuntimeException("Failed to create the GLFW window");
        }

        // Setup a key callback. It will be called every time a key is pressed, repeated or released.
        glfwSetKeyCallback(window, keyCallback = new GLFWKeyCallback() {
            @Override
            public void invoke(long window, int key, int scancode, int action, int mods) {
                if (key == GLFW_KEY_ESCAPE && action == GLFW_RELEASE) {
                    glfwSetWindowShouldClose(window, GL_TRUE); // We will detect this in our rendering loop
                }
            }
        });

        // Get the resolution of the primary monitor
        ByteBuffer vidmode = glfwGetVideoMode(glfwGetPrimaryMonitor());
        // Center our window
        glfwSetWindowPos(window, (GLFWvidmode.width(vidmode) - WIDTH) / 2,
                (GLFWvidmode.height(vidmode) - HEIGHT) / 2);

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

        // Make the window visible
        glfwShowWindow(window);

        // 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 ContextCapabilities instance and makes the OpenGL
        // bindings available for use.
        GLContext.createFromCurrent();

        // Set the clear color
        glClearColor(1.0f, 1.0f, 1.0f, 0.0f);
    }

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

            /* Render triangle */
            glColor3f(1f, 0f, 0f);
            glBegin(GL_TRIANGLES);
            glVertex3f(-0.6f, -0.4f, 0f);
            glVertex3f(0.6f, -0.4f, 0f);
            glVertex3f(0f, 0.6f, 0f);
            glEnd();

            /* Swap buffers and poll Events */
            glfwSwapBuffers(window); // swap the color buffers

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