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This program demonstrates when to issue lighting and transformation commands to render a model with a light which is moved by a modeling transformation (rotate or translate). The light position is reset after the modeling transformation is called. The eye position does not change.
A sphere is drawn using a grey material characteristic. A single light source
illuminates the object.
Interaction: pressing the left or middle mouse button alters the modeling
transformation (x rotation) by 30 degrees. The scene is then redrawn with the
light in a new position.
The example is ported from C examples in the OpenGL Programming Guide (known as the "red book").
-> Copyright and Permission Notice
package glredbook10;
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import java.nio.*;
import javax.media.opengl.*;
import javax.media.opengl.glu.*;
import com.sun.opengl.util.*;
/**
* This program demonstrates when to issue lighting and transformation commands
* to render a model with a light which is moved by a modeling transformation
* (rotate or translate). The light position is reset after the modeling
* transformation is called. The eye position does not change. <br>
* <br>
* A sphere is drawn using a grey material characteristic. A single light source
* illuminates the object. <br>
* <br>
* Interaction: pressing the left or middle mouse button alters the modeling
* transformation (x rotation) by 30 degrees. The scene is then redrawn with the
* light in a new position.
*
* @author Kiet Le (Java port)
*/
public class movelight
extends JFrame
implements GLEventListener, KeyListener, MouseListener,
MouseMotionListener, MouseWheelListener
{
private GLU glu;
private GLUT glut;
private GLCapabilities caps;
private GLCanvas canvas;
private FPSAnimator animator;
private static int spin = 0;
public movelight()
{
super("movelight");
caps = new GLCapabilities();
canvas = new GLCanvas(caps);
canvas.addGLEventListener(this);
canvas.addKeyListener(this);
canvas.addMouseListener(this);
getContentPane().add(canvas);
}
public void run()
{
setSize(500, 500);
setLocationRelativeTo(null);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setVisible(true);
canvas.requestFocusInWindow();
}
public static void main(String[] args)
{
new movelight().run();
}
public void init(GLAutoDrawable drawable)
{
GL gl = drawable.getGL();
glu = new GLU();
glut = new GLUT();
gl.glEnable(GL.GL_LIGHTING);
gl.glEnable(GL.GL_LIGHT0);
gl.glDepthFunc(GL.GL_LESS);
gl.glEnable(GL.GL_DEPTH_TEST);
}
/*
* Here is where the light position is reset after the modeling transformation
* (glRotated) is called. This places the light at a new position in world
* coordinates. The cube represents the position of the light.
*/
public void display(GLAutoDrawable drawable)
{
GL gl = drawable.getGL();
float position[] =
{ 0.0f, 0.0f, 1.5f, 1.0f };
gl.glClear(GL.GL_COLOR_BUFFER_BIT | GL.GL_DEPTH_BUFFER_BIT);
gl.glPushMatrix();
gl.glTranslatef(0.0f, 0.0f, -5.0f);
gl.glPushMatrix();
gl.glRotated((double) spin, 1.0, 0.0, 0.0);
gl.glRotated(0.0, 1.0, 0.0, 0.0);
gl.glLightfv(GL.GL_LIGHT0, GL.GL_POSITION, position, 0);
gl.glTranslated(0.0, 0.0, 1.5);
gl.glDisable(GL.GL_LIGHTING);
gl.glColor3f(0.0f, 1.0f, 1.0f);
glut.glutWireCube(0.1f);
gl.glEnable(GL.GL_LIGHTING);
gl.glPopMatrix();
glut.glutSolidTorus(0.275f, 0.85f, 20, 20);
gl.glPopMatrix();
gl.glFlush();
}
public void reshape(GLAutoDrawable drawable, int x, int y, int w, int h)
{
GL gl = drawable.getGL();
gl.glViewport(0, 0, w, h);
gl.glMatrixMode(GL.GL_PROJECTION);
gl.glLoadIdentity();
glu.gluPerspective(40.0, (float) w / (float) h, 1.0, 20.0);
gl.glMatrixMode(GL.GL_MODELVIEW);
}
public void displayChanged(GLAutoDrawable drawable, boolean modeChanged,
boolean deviceChanged)
{
}
private void movelight()
{
spin = (spin + 30) % 360;
}
public void keyTyped(KeyEvent key)
{
}
public void keyPressed(KeyEvent key)
{
char ch = key.getKeyChar();
switch (ch) {
case KeyEvent.VK_ESCAPE:
System.exit(0);
break;
default:
break;
}
}
public void keyReleased(KeyEvent key)
{
}
public void mouseClicked(MouseEvent mouse)
{
}
public void mousePressed(MouseEvent mouse)
{
if (mouse.getButton() == MouseEvent.BUTTON1) //
movelight();
canvas.display();
}
public void mouseReleased(MouseEvent mouse)
{
}
public void mouseEntered(MouseEvent mouse)
{
}
public void mouseExited(MouseEvent mouse)
{
}
public void mouseDragged(MouseEvent mouse)
{
}
public void mouseMoved(MouseEvent mouse)
{
}
public void mouseWheelMoved(MouseWheelEvent wheel)
{
}
}
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Source:
Kiet Le's The Red Book Examples using JOGL
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