CODEWITHSUNDEEP
javaopenglcamerajogl
Joey
Joey

Reputation: 47

How to make the camera move in the direction of the rotation?

How can I make the camera move in the direction of the rotation? How do I calculate the position of the camera to follow the rotation? This is my code: 

import javax.media.opengl.*;
import javax.media.opengl.awt.*;
import com.sun.opengl.util.*;
import com.sun.opengl.util.gl2.GLUT;
import javax.media.opengl.glu.*;

import java.awt.event.*;
import java.awt.*;
import javax.swing.*;

public class Rotation2 extends JFrame implements GLEventListener, KeyListener
{
    GLCanvas canvas = null;
    Animator an;

    public Rotation2()
    {   
        canvas=new GLCanvas();
        an=new Animator(canvas);
        add(canvas);
        canvas.addGLEventListener(this);
        canvas.addKeyListener(this);
        setSize(1280,900);
        setVisible(true);
        setDefaultCloseOperation(EXIT_ON_CLOSE);
        an.start();
        requestFocus();

    }
    float xPosition = 0;
    float zPosition = 0;

    float red = 0;
    float green = 0;
    float blue = 1;


    public void init(GLAutoDrawable drawable)
    {
        GL2 gl = drawable.getGL().getGL2();
        GLU glu = new GLU();
        gl.glMatrixMode(GL2.GL_PROJECTION);
        gl.glLoadIdentity();

        double w = drawable.getWidth();
        double h = drawable.getHeight();
        double aspect = w/h;
        glu.gluPerspective(60.0, aspect, 2.0, 20.0);

    }
    double zRot = 0;
    double xRot = 0;

    public void display(GLAutoDrawable drawable)
    {
        GL2 gl=drawable.getGL().getGL2();
        GLU glu = new GLU();
        GLUT glut = new GLUT();

        gl.glMatrixMode(GL2.GL_MODELVIEW);
        gl.glLoadIdentity();
        gl.glClearColor(0f,0f,0f,0f);
        //xPosition+=0.005;
        //zPosition+=0.005;
        gl.glRotated(zRot, 0, 1, 0);
        gl.glRotated(xRot, 1, 0, 0);
        glu.gluLookAt(xPosition, 0, zPosition,
                      xPosition, 0, (zPosition+20),
                      0, 1, 0);

        gl.glClear(GL2.GL_COLOR_BUFFER_BIT);

        red = 0.0f;
        green = 0.0f;
        blue = 0.9f;
        gl.glColor3f(red, green, blue);
//transforming the place the next shape
//will be drawn.
        gl.glTranslated(2, 0, 2);
//We use wire here because default
//lighting is not good enough to
//use when rendering the solid version
        glut.glutWireIcosahedron();
//more shapes to navigate through
        gl.glTranslated(-4, 0, 0);
        glut.glutWireIcosahedron();
        red = 0.0f;
        green = 0.9f;
        blue = 0.1f;
        gl.glColor3f(red, green, blue);
        gl.glTranslated(4, 0, 4);
        glut.glutWireIcosahedron();
        gl.glTranslated(-4, 0, 0);
        glut.glutWireIcosahedron();
        red = 0.9f;
        green = 0.0f;
        blue = 0.1f;
        gl.glColor3f(red, green, blue);
        gl.glTranslated(4, 0, 4);
        glut.glutWireIcosahedron();
        gl.glTranslated(-4, 0, 0);
        glut.glutWireIcosahedron();
        red = 0.9f;
        green = 0.0f;
        blue = 0.9f;
        gl.glColor3f(red, green, blue);
        gl.glTranslated(4, 0, 4);
        glut.glutWireIcosahedron();
        gl.glTranslated(-4, 0, 0);
        glut.glutWireIcosahedron();


    }

    public void reshape(GLAutoDrawable drawable,int x,int y,int width,int height)
    {}
    public void dispose(GLAutoDrawable drawable)
    {}


    public static void main(String[] ar)
    {

        new Rotation2();
    }

    @Override
    public void keyTyped(KeyEvent e) {

    }

    @Override
    public void keyPressed(KeyEvent e) {
        if (e.getKeyCode() == KeyEvent.VK_W) {
            zPosition++;
        }
        else if (e.getKeyCode() == KeyEvent.VK_S) {
            zPosition--;
        }
        else if(e.getKeyCode() == KeyEvent.VK_A) {
            xPosition++;
        }
        else if (e.getKeyCode() == KeyEvent.VK_D) {
            xPosition--;
        }
        if (e.getKeyCode() == KeyEvent.VK_RIGHT) {
            zRot+=5;
        }
        else if (e.getKeyCode() == KeyEvent.VK_LEFT) {
            zRot-=5;
        }
        else if (e.getKeyCode() == KeyEvent.VK_UP) {
            xRot-=5;
        }
        else if (e.getKeyCode() == KeyEvent.VK_DOWN) {
            xRot+=5;
        }
        canvas.repaint();
    }

    @Override
    public void keyReleased(KeyEvent e) {

    }
}

p.s. You have to click the canvas for things to start working.

Upvotes: 0

Views: 464

Answers (1)

gouessej
gouessej

Reputation: 4075

elect is right, you have to understand the basic concepts, you can't just tinker with no understanding of the notions on computer graphics. You can read the OpenGL Red Book, its code examples have been ported to JOGL and are available on Github here.

Those classes of my own first person shooter's very oldest alpha version show how to implement a camera except that you cannot look up or down: GameGLView GameController GameModel

P.S: I have to update it soon to make it work with JOGL 2.3.2 and later. It works with JOGL 2.3.1.

P.P.S: I updated the source code above to make it work with JOGL 2.3.2 yesterday (February, 4th, 2016).

Upvotes: 2

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