Develop Reference

How to move camera eye position in JOGL?

I'm trying to move the camera in jogl but my code doesn't seem to do anything. How do you move the camera with keyboard input? I'm drawing a rotating hexagon and I want to move the camera but I can't seem to get it working. 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;
Animator an;
public Rotation2()
{
canvas=new GLCanvas();
an=new Animator(canvas);
add(canvas);
canvas.addGLEventListener(this);
canvas.addKeyListener(this);
setSize(600,400);
setVisible(true);
setDefaultCloseOperation(EXIT_ON_CLOSE);
an.start();
}
double eyeX = 0;
double eyeY = 0;
double eyeZ = 0;
public void init(GLAutoDrawable drawable)
{
GL2 gl=drawable.getGL().getGL2();
GLU glu = new GLU();
gl.glClearColor(0.0f,0.0f,0.0f,0.0f);
gl.glMatrixMode(GL2.GL_PROJECTION);
gl.glOrtho(-300,300,-200,200,200,-200);
//gl.glLoadIdentity();
gl.glMatrixMode(GL2.GL_MODELVIEW);
//glu.gluLookAt(5, 5, 5,0, 0, 0, 1, 100, 0);
gl.glClearDepth(1.0f); // Set background depth to farthest
gl.glEnable(GL2.GL_DEPTH_TEST); // Enable depth testing for z-culling
gl.glDepthFunc(GL2.GL_LEQUAL); // Set the type of depth-test
}
double x=0;
public void display(GLAutoDrawable drawable)
{
GL2 gl=drawable.getGL().getGL2();
gl.glClear(GL2.GL_COLOR_BUFFER_BIT | GL2.GL_DEPTH_BUFFER_BIT);
gl.glEnable(GL2.GL_DEPTH_TEST);
gl.glLoadIdentity();
GLU glu=new GLU();
//gl.glPushMatrix();
gl.glScaled(2,2,2);
gl.glRotated(x,1,1,1);
x+=.05;
glu.gluLookAt(eyeX, eyeY, 2,0, 0, 0, 1, 100, 0);
gl.glColor3f(0,1f,0);
// front
gl.glBegin(GL2.GL_POLYGON);
gl.glVertex3d(25,50,25);
gl.glVertex3d(-25,50,25);
gl.glVertex3d(-50,0,25);
gl.glVertex3d(-25,-50,25);
gl.glVertex3d(25,-50,25);
gl.glVertex3d(50,0,25);
gl.glEnd();
//left
gl.glColor3f(1f,1f,0);
gl.glBegin(GL2.GL_POLYGON);
gl.glVertex3d(25,50,-25);
gl.glVertex3d(-25,50,-25);
gl.glVertex3d(-50,0,-25);
gl.glVertex3d(-25,-50,-25);
gl.glVertex3d(25,-50,-25);
gl.glVertex3d(50,0,-25);
gl.glEnd();
gl.glColor3f(1f,0f,0);
gl.glBegin(GL2.GL_POLYGON);
gl.glVertex3d(25,50,25);
gl.glVertex3d(25,50,-25);
gl.glVertex3d(-25,50,-25);
gl.glVertex3d(-25,50,25);
gl.glEnd();
gl.glColor3f(0f,0f,1f);
gl.glBegin(GL2.GL_POLYGON);
gl.glVertex3d(-25,50,25);
gl.glVertex3d(-25,50,-25);
gl.glVertex3d(-50,0,-25);
gl.glVertex3d(-50,0,25);
gl.glEnd();
gl.glColor3f(1f,1f,1f);
gl.glBegin(GL2.GL_POLYGON);
gl.glVertex3d(-50,0,25);
gl.glVertex3d(-50,0,-25);
gl.glVertex3d(-25,-50,-25);
gl.glVertex3d(-25,-50,25);
gl.glEnd();
gl.glColor3f(0,1f,1f);
gl.glBegin(GL2.GL_POLYGON);
gl.glVertex3d(-25,-50,25);
gl.glVertex3d(-25,-50,-25);
gl.glVertex3d(25,-50,-25);
gl.glVertex3d(25,-50,25);
gl.glEnd();
gl.glColor3f(1,0f,1f);
gl.glBegin(GL2.GL_POLYGON);
gl.glVertex3d(25,-50,25);
gl.glVertex3d(25,-50,-25);
gl.glVertex3d(50,0,-25);
gl.glVertex3d(50,0,25);
gl.glEnd();
gl.glColor3f(.2f,1f,.2f);
gl.glBegin(GL2.GL_POLYGON);
gl.glVertex3d(50,0,25);
gl.glVertex3d(50,0,-25);
gl.glVertex3d(25,50,-25);
gl.glVertex3d(25,50,25);
gl.glEnd();
//gl.glPopMatrix();
}
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) {
if (e.getKeyCode() == KeyEvent.VK_X) {
eyeX++;
}
else if (e.getKeyCode() == KeyEvent.VK_Y) {
eyeY++;
}
else if(e.getKeyCode() == KeyEvent.VK_Z) {
eyeZ++;
}
else {
}
}
#Override
public void keyPressed(KeyEvent e) {
}
#Override
public void keyReleased(KeyEvent e) {
}
}

that's deprecated opengl, forget it.
You are also using a very old jogl, update it, go on jogamp.org, under "Builds / Download" click on "zip", then download jogamp-all-platforms.7z extract it and set jogl as explained here
Take this Hello Triangle.
It uses already the keyListener, just copy the code you wrote for the keyTyped and paste it under keyPressed (you have to use the jogamp keyListener, what you use in your sample is instead the java awt one).
Let us know if you have any problem :)

JOGL, Animator, Scaling, Overlay

I have two graphics objects. Each object is made up of tens of thousands of triangle primitives. For the sake of this example, let`s just consider the two objects as triangles - blue triangle and orange triangles.
I want to draw the blue triangle once in the background, and use the animator to over lay the several orange triangles over the blue. Think about the blue triangle as a canvas and the orange triangles are drawn over them in a pattern. Now the canvas and the orange triangles are rotated as a whole. Also, how can I scale the whole set up and rotate them around a different axes?
In this example, I want all the orange triangles to over lay on the blue.
Here is the SSCCE. If you see in the example, the blue triangles over lay on the orange. I want all the orange triangles to be on top of blue.
Also, how do I clear the canvas from an external event like a button click and completely start redrawing the scene?
import java.awt.EventQueue;
import javax.swing.JFrame;
import com.jogamp.opengl.GL2;
import com.jogamp.opengl.GLAutoDrawable;
import com.jogamp.opengl.GLCapabilities;
import com.jogamp.opengl.GLEventListener;
import com.jogamp.opengl.GLProfile;
import com.jogamp.opengl.awt.GLCanvas;
import com.jogamp.opengl.util.Animator;
import javax.swing.JButton;
import java.awt.BorderLayout;
import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;
public class MainWin implements GLEventListener {
private JFrame frame;
private int iter = 0;
private float rotAng = 0;
private GLProfile profile;
private GLCapabilities capabilities;
private GLCanvas canvas;
private Animator animator;
private int totIter = 15;
private float scaleFac = 1f;
/**
* Launch the application.
*/
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
public void run() {
try {
MainWin window = new MainWin();
window.frame.setVisible(true);
} catch (Exception e) {
e.printStackTrace();
}
}
});
}
/**
* Create the application.
*/
public MainWin() {
initialize();
}
/**
* Initialize the contents of the frame.
*/
private void initialize() {
frame = new JFrame();
frame.setBounds(100, 100, 600, 450);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JButton btnZoom = new JButton("Zoom");
btnZoom.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent arg0) {
zoomObj();
}
private void zoomObj() {
canvas.invalidate();
scaleFac -= 0.5f;
}
});
frame.getContentPane().add(btnZoom, BorderLayout.NORTH);
// Initilaize graphics profile, capabilites, canvas and animator
profile = GLProfile.get(GLProfile.GL2);
capabilities = new GLCapabilities(profile);
capabilities.setNumSamples(2);
capabilities.setSampleBuffers(true);
canvas = new GLCanvas(capabilities);
canvas.addGLEventListener(this);
canvas.requestFocusInWindow();
animator = new Animator();
animator.add(canvas);
animator.start();
frame.getContentPane().add(canvas); // add to the frame
}
#Override
public void display(GLAutoDrawable drawable) {
GL2 gl = drawable.getGL().getGL2();
gl.glRotatef(15, 0, 1, 0); // rotate both blue and orange objects around Y axis
gl.glScalef(scaleFac, scaleFac, scaleFac);
//blue object
gl.glPolygonMode(GL2.GL_FRONT_AND_BACK, GL2.GL_FILL);
gl.glEnable(GL2.GL_MULTISAMPLE);
gl.glPushMatrix();
gl.glCallList(2);
gl.glPopMatrix();
gl.glDisable(GL2.GL_MULTISAMPLE);
// orange object
gl.glPolygonMode(GL2.GL_FRONT_AND_BACK, GL2.GL_LINE);
if (iter < totIter) {
iter++;
rotAng = 5;
gl.glRotatef((float) rotAng, 0, 0, 1); // rotate each iter by 5 aroung Z. Only the orange.
gl.glEnable(GL2.GL_MULTISAMPLE);
gl.glPushMatrix();
gl.glCallList(1);
gl.glPopMatrix();
gl.glDisable(GL2.GL_MULTISAMPLE);
try {
Thread.sleep(500);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
if (iter == totIter - 1) {
animator.stop();
}
gl.glFlush();
}
#Override
public void dispose(GLAutoDrawable drawable) {
}
#Override
public void init(GLAutoDrawable drawable) {
GL2 gl = drawable.getGL().getGL2();
gl.glClearColor(.0f, .0f, .2f, 0.9f);
gl.glClear(GL2.GL_COLOR_BUFFER_BIT | GL2.GL_DEPTH_BUFFER_BIT);
gl.glLoadIdentity();
// buffers for multisampling
int buf[] = new int[1];
int sbuf[] = new int[1];
gl.glGetIntegerv(GL2.GL_SAMPLE_BUFFERS, buf, 0);
gl.glGetIntegerv(GL2.GL_SAMPLES, sbuf, 0);
initObj1(gl); // Orange
initObj2(gl); // Blue
}
/**
* Blue triangle. In actual code, this is a complicated 3D object made up of atleast a few tens of thousands of
* primitives in a mesh.
*
* #param gl
*/
private void initObj2(GL2 gl) {
gl.glNewList(2, GL2.GL_COMPILE);
gl.glColorMaterial(GL2.GL_FRONT, GL2.GL_DIFFUSE);
gl.glEnable(GL2.GL_COLOR_MATERIAL);
gl.glBegin(GL2.GL_TRIANGLES);
gl.glColor4f(.2f, .5f, 0.8f, 0.5f);
gl.glVertex3f(-0.5f, 0, 0);
gl.glVertex3f(0.5f, 0, 0);
gl.glVertex3f(0, 0.5f, 0);
gl.glEnd();
gl.glEndList();
}
/**
* Orange Triangle. In actual code, this is a complicated 3D object made up of atleast a few tens of thousands of
* primitives in a mesh.
*
* #param gl
*/
private void initObj1(GL2 gl) {
gl.glNewList(1, GL2.GL_COMPILE);
gl.glColorMaterial(GL2.GL_FRONT, GL2.GL_DIFFUSE);
gl.glEnable(GL2.GL_COLOR_MATERIAL);
gl.glBegin(GL2.GL_TRIANGLES);
gl.glColor4f(.95f, .45f, 0.15f, 0.5f);
gl.glVertex3f(-1, 0, 0);
gl.glVertex3f(1, 0, 0);
gl.glVertex3f(0, 1, 0);
gl.glEnd();
gl.glEndList();
}
#Override
public void reshape(GLAutoDrawable drawable, int x, int y, int w, int h) {
}
}

JOGL display function got called twice

I'm very new to JOGL, hence please pardon the question's noobness.
I'm trying to write a piece of toy code to output a single square using GLCanvas, which is positioned randomly on the canvas. However, the display function seems to get called twice (and hence two squares appear, rather than one). Here's the code. Where did I go wrong?
RandomPoint class:
import java.awt.BorderLayout;
import java.awt.Frame;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import javax.media.opengl.GL2;
import javax.media.opengl.GLAutoDrawable;
import javax.media.opengl.GLCapabilities;
import javax.media.opengl.GLEventListener;
import javax.media.opengl.GLProfile;
import javax.media.opengl.awt.GLCanvas;
public class RandomPoints extends Frame implements GLEventListener{
/**
*
*/
private static final long serialVersionUID = 1L;
public int HEIGHT;
public int WIDTH;
private GLCanvas canvas;
//private Animator animator;
public RandomPoints(){
HEIGHT = 300;
WIDTH = 300;
GLProfile profile = GLProfile.getDefault();
GLCapabilities cap = new GLCapabilities(profile);
canvas = new GLCanvas(cap);
add(canvas, BorderLayout.CENTER);
canvas.addGLEventListener(this);
System.out.println("Probe");
addWindowListener(new WindowAdapter(){
public void windowClosing(WindowEvent e){
//animator.stop();
System.exit(0);
}
});
}
#Override
public void display(GLAutoDrawable arg0) {
//TODO Auto-generated method stub
GL2 gl = arg0.getGL().getGL2();
float red = (float) Math.random();
float blue = (float) Math.random();
float green = (float) Math.random();
int x = (int)(Math.random()*WIDTH);
int y = (int)(Math.random()*HEIGHT);
gl.glColor3f(red, green, blue);
gl.glBegin(GL2.GL_POLYGON);
gl.glVertex2i(x, y);
gl.glVertex2i(x+10, y);
gl.glVertex2i(x+10, y+10);
gl.glVertex2i(x, y+10);
gl.glEnd();
System.out.println(x+" "+y+" "+red+" "+green+" "+blue);
}
#Override
public void dispose(GLAutoDrawable arg0) {
// TODO Auto-generated method stub
}
#Override
public void init(GLAutoDrawable arg0) {
// TODO Auto-generated method stub
GL2 gl = arg0.getGL().getGL2();
gl.glColor3f(0.0f, 0.0f, 0.0f);
gl.glClearColor(1, 1, 1, 0);
gl.glClear(GL2.GL_COLOR_BUFFER_BIT);
//animator = new Animator(canvas);
//animator.start();
}
#Override
public void reshape(GLAutoDrawable arg0, int arg1, int arg2, int arg3, int arg4) {
// TODO Auto-generated method stub
WIDTH = arg3; HEIGHT = arg4;
GL2 gl = arg0.getGL().getGL2();
gl.glMatrixMode(GL2.GL_PROJECTION);
gl.glLoadIdentity();
gl.glOrtho(0, WIDTH, 0, HEIGHT, -1, 1);
}
}
GLTest class (driver)
public class GLTest {
public static void main(String args[]){
RandomPoints point = new RandomPoints();
point.setSize(300,300);
point.setVisible(true);
}
}
Thanks in advance!

I've just tested your code and I see only one square. However, it would be better to clear the color buffer in the display() method too. You should look at my example here. If you really want to animate your drawing, you should use an animator. Please rather post your questions about JOGL on its official forum if you want to get more accurate and faster replies as only a very few maintainers come here.

NullPointerException with libgdx using the gdx render() method

Started making a game.
Here's some of my code.
package games.tribe.screens;
import games.tribe.model.World;
import games.tribe.view.WorldRenderer;
import com.badlogic.gdx.Gdx;
import com.badlogic.gdx.Screen;
import com.badlogic.gdx.graphics.GL10;
public class GameScreen implements Screen {
private World world;
private WorldRenderer renderer;
/** This was the bit I'd missed --------------------------------------**/
#Override
public void show() {
world = new World();
renderer = new WorldRenderer(world);
}
/**------------------------------------------------------------------**/
#Override
public void render(float delta) {
Gdx.gl.glClearColor(0.1f, 0.1f, 0.1f, 1);
Gdx.gl.glClear(GL10.GL_COLOR_BUFFER_BIT);
renderer.render();
}
#Override
public void resize(int width, int height) {
// TODO Auto-generated method stub
}
#Override
public void hide() {
// TODO Auto-generated method stub
}
#Override
public void pause() {
// TODO Auto-generated method stub
}
#Override
public void resume() {
// TODO Auto-generated method stub
}
#Override
public void dispose() {
// TODO Auto-generated method stub
}
}
here's the WorldRenderer Class:
package games.tribe.view;
import com.badlogic.gdx.graphics.Color;
import com.badlogic.gdx.graphics.OrthographicCamera;
import com.badlogic.gdx.graphics.glutils.ShapeRenderer;
import com.badlogic.gdx.graphics.glutils.ShapeRenderer.ShapeType;
import com.badlogic.gdx.math.Rectangle;
import games.tribe.model.Block;
import games.tribe.model.TribalHunter;
import games.tribe.model.World;
public class WorldRenderer {
private World world;
private OrthographicCamera cam;
/**for debug rendering**/
ShapeRenderer debugRenderer = new ShapeRenderer();
public WorldRenderer(World world) {
this.world = world;
this.cam = new OrthographicCamera(10, 7);
this.cam.position.set(5, 3.5f, 0);
this.cam.update();
}
public void render() {
//render blocks
debugRenderer.setProjectionMatrix(cam.combined);
debugRenderer.begin(ShapeType.Rectangle);
for(Block block : world.getBlocks()) {
Rectangle rect = block.getBounds();
float x1 = block.getPosition().x + rect.x;
float y1 = block.getPosition().y + rect.y;
debugRenderer.setColor(new Color(1, 0, 0, 1));
debugRenderer.rect(x1, y1, rect.width, rect.height);
}
//render hunter
TribalHunter hunter = world.getHunter();
Rectangle rect = hunter.getBounds();
float x1 = hunter.getPosition().x + rect.x;
float y1 = hunter.getPosition().y + rect.y;
debugRenderer.setColor(new Color(0, 1, 0, 1));
debugRenderer.rect(x1, y1, rect.width, rect.height);
debugRenderer.end();
}
}
This is the exception I'm getting when I run it as a desktop application:
Exception in thread "LWJGL Application" java.lang.NullPointerException
at games.tribe.screens.GameScreen.render(GameScreen.java:19)
at com.badlogic.gdx.Game.render(Game.java:46)
at com.badlogic.gdx.backends.lwjgl.LwjglApplication.mainLoop(LwjglApplication.java:202)
at com.badlogic.gdx.backends.lwjgl.LwjglApplication$1.run(LwjglApplication.java:131)
AL lib: ReleaseALC: 1 device not closed
Line 46 of gdx.Game.render is this method:
#Override
public void render () {
if (screen != null) screen.render(Gdx.graphics.getDeltaTime());
}
Any help will be appreciated
Thanks in advance

In the GameScreen's render() method, has the renderer been initialized? That could be causing the problem if it hasn't.
Edit: The problem you're having, according to the top two lines of the error, is a NullPointerException on line 19 of the class GameScreen. The NullPointerException only occurs when an object is used for some action when the object itself is null because it likely hasn't been initialized.
Line 19 of the GameScreen is:
renderer.render();
...but the object renderer has not been initialized anywhere, so it is currently null which is the default. To avoid getting this error, you'll need to initialize the renderer object before you run that line of code. Perhaps with something like this:
#Override
public void render(float delta) {
Gdx.gl.glClearColor(0.1f, 0.1f, 0.1f, 1);
Gdx.gl.glClear(GL10.GL_COLOR_BUFFER_BIT);
renderer = new WorldRenderer();
renderer.render();
}
I am not familiar with libgdx, so I can't be sure that's exactly how a WorldRenderer is initialized, but you need to do something of the sort. I hope this helps.

JOGL white texture?

I am trying to load earth.png and place it over a triangle. The image is 256x256. I have followed an online tutorial and played around with this for hours, but the triangle still remains white. Can any one point me in the right direction.
import java.awt.Frame;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import java.io.IOException;
import java.io.InputStream;
import javax.media.opengl.*;
import javax.media.opengl.awt.GLCanvas;
import com.jogamp.opengl.util.texture.Texture;
import com.jogamp.opengl.util.texture.TextureData;
import com.jogamp.opengl.util.texture.TextureIO;
public class test implements GLEventListener {
private Texture earthTexture;
public static void main(String[] args) {
GLProfile glp = GLProfile.getDefault();
GLCapabilities caps = new GLCapabilities(glp);
GLCanvas canvas = new GLCanvas(caps);
final Frame frame = new Frame("AWT Window Test111");
frame.setSize(700, 700);
frame.add(canvas);
frame.setVisible(true);
// by default, an AWT Frame doesn't do anything when you click
// the close button; this bit of code will terminate the program when
// the window is asked to close
frame.addWindowListener(new WindowAdapter() {
public void windowClosing(WindowEvent e) {
frame.dispose();
System.exit(0);
}
});
canvas.addGLEventListener(new test());
}
#Override
public void display(GLAutoDrawable arg0) {
update();
render(arg0);
}
private void update() {
// TODO Auto-generated method stub
}
private void render(GLAutoDrawable drawable) {
GL2 gl = drawable.getGL().getGL2();
gl.glClear(GL.GL_COLOR_BUFFER_BIT);
gl.glEnable(GL.GL_TEXTURE_2D);
gl.glBegin(GL2.GL_TRIANGLES); // Begin drawing triangle sides
earthTexture.enable();
earthTexture.bind();
// gl.glColor3f( 1.0f, 0.0f, 0.0f); // Set colour to red
gl.glTexCoord2f(0.0f, 0.0f);
gl.glVertex3f( 0.0f, 1.0f, 1.0f); // Top vertex
gl.glTexCoord2f(-1.0f, -2.0f);
gl.glVertex3f(-1.0f,-1.0f, 0.0f); // Bottom left vertex
gl.glTexCoord2f(1.0f, -2.0f);
gl.glVertex3f( 1.0f,-1.0f, 0.0f); // Bottom right vertex
gl.glEnd();
}
#Override
public void dispose(GLAutoDrawable arg0) {
// TODO Auto-generated method stub
}
#Override
public void init(GLAutoDrawable arg0) {
GL2 gl = arg0.getGL().getGL2();
// Load texture.
try {
InputStream stream = getClass().getResourceAsStream("earth.png");
TextureData data = TextureIO.newTextureData(gl.getGLProfile(), stream, 100, 200, false, "png");
earthTexture = TextureIO.newTexture(data);
}
catch (IOException exc) {
exc.printStackTrace();
System.exit(1);
}
}
#Override
public void reshape(GLAutoDrawable arg0, int arg1, int arg2, int arg3,
int arg4) {
// TODO Auto-generated method stub
}
}

You are binding your texture in between the glBegin/glEnd statements. It is required to do so before the glBegin. Texture switches in between begin/end pairs are likely to be ignored.

A couple of things I have noticed:
You need to explicitly enable texturing within OpenGL, by using something like:
gl.glEnable(GL.GL_TEXTURE_2D);
You also will need to specify coordinates for the textures (typically expressed as u,v coordinates), this needs to be done for every 3D point:
gl.glTexCoord2f(0.0f, 0.0f);
gl.glVertex3f( 0.0f, 1.0f, 1.0f);
...
The excellent NeHe tutorials also have JOGL sample code these days, which will be worthwhile looking at in more depth:
http://nehe.gamedev.net/data/lessons/lesson.asp?lesson=07
This article also has some good information on understanding texture coordiantes:
http://www.opengl.org/resources/code/samples/sig99/advanced99/notes/node52.html