CODEWITHSUNDEEP
javaopenglgraphicslwjgl
Tarmiac
Tarmiac

Reputation: 862

Making a triangle rotate in LWJGL3 with keycallback

So, how do I rotate a triangle by pressing Up, Down, Left or Right. I have a Keyboard class which can read keys and create events. But I don't know the function for rotating in LWJGL 3. I think I'm familiar with the classic gl.h way of rotating, but since LWJGL 3 is pretty new there aren't alot of information on this. Here is code for Display class and KeyboardHandler class.

Display

public class Driver implements Runnable{

private GLFWKeyCallback keyCallback;
private Thread thread = new Thread();
private boolean running = false;


public long window;

private static final int WIDTH = 600;
private static final int HEIGHT = WIDTH / 12 * 9;

public Driver(){

}

private synchronized void start(){
    thread.start();
    running = true;
}

private synchronized void stop(){
    try {
        thread.join();
        running = false;
    } catch (InterruptedException e) {
        e.printStackTrace();
    }
}

public void run(){
    init();
    while(running){

        render();
        update();

        if(glfwWindowShouldClose(window) == GL_TRUE){
            running = false;
            keyCallback.release();
        }
    }
}

public void init() {

    if(glfwInit() != GL_TRUE){
        System.err.println("Failed to initilaize OpenGL");
    }

    glfwWindowHint(GLFW_RESIZABLE, GL_FALSE);
    window = glfwCreateWindow(WIDTH, HEIGHT, "Endless", NULL, NULL);

    if(window == NULL){
        System.err.println("Could not create window. ");
    }

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

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

}


public void update() {
    if(KeyboardHandler.isKeyDown(GLFW_KEY_LEFT)){
        //event who'll start rotation
    }
    glfwPollEvents();
}

public void render() {

    GLContext.createFromCurrent();

    glBegin(GL_TRIANGLES);
    glColor3f(1.0f, 0.0f, 0.0f);
    glVertex2f(-1.0f / 2, -1.0f / 2);
    glColor3f(0.0f, 1.0f, 0.0f);
    glVertex2f(0.0f / 2, 1.0f / 2);
    glColor3f(0.0f, 0.0f, 1.0f);
    glVertex2f(1.0f / 2, -1.0f / 2);
    glEnd();

    //rotation of triangle

    glfwSwapBuffers(window);
}


public static void main(String[] args) {
    Driver game = new Driver();
    game.start();
    game.run();
}

}

And KeyboardHandler

public class KeyboardHandler extends GLFWKeyCallback{

private static boolean keys[] = new boolean[65536];

public void invoke(long window, int key, int scancode, int action, int mods)         
{   
keys[key] = action != GLFW_RELEASE;
}

public static boolean isKeyDown(int keycode){
    return keys[keycode];
}

}

I guess the rotation itself should happen in render() while the keycallback who triggers it should be in update()

Upvotes: 0

Views: 205

Answers (1)

user3002851
user3002851

Reputation:

With the introduction of LWJGL 3, you must use shaders to rotate, scale, and transform your objects. You can find many resources on the internet that show you how to do this, one of them being the OpenGL programming WikiBook. Specifically, in tutorial four, which deals with rotating objects in modern OpenGL

Upvotes: 1

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