package glredbook10;
import javax.swing.*;
import java.awt.event.*;
import javax.media.opengl.*;
import javax.media.opengl.glu.*;
/**
* This program draws several overlapping filled polygons to demonstrate the
* effect order has on alpha blending results. Use the 't' key to toggle the
* order of drawing polygons.
*
* @author: Kiet Le (Java conversion)
*/
public class alpha
extends JFrame
implements GLEventListener, KeyListener
{
private GLCanvas canvas;
public alpha()
{
super("alpha");
canvas = new GLCanvas();
canvas.addGLEventListener(this);
canvas.addKeyListener(this);
getContentPane().add(canvas);
}
public void run()
{
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setSize(500, 500);
setLocationRelativeTo(null);
setVisible(true);
canvas.requestFocusInWindow();
}
/*
* Main Loop Open window with initial window size, title bar, RGBA display
* mode, and handle input events.
*/
public static void main(String[] args)
{
new alpha().run();
}
/*
* Initialize alpha blending function.
*/
public void init(GLAutoDrawable drawable)
{
GL gl = drawable.getGL();
//
gl.glEnable(GL.GL_BLEND);
gl.glBlendFunc(GL.GL_SRC_ALPHA, GL.GL_ONE_MINUS_SRC_ALPHA);
gl.glShadeModel(GL.GL_FLAT);
gl.glClearColor(0, 0, 0, 0);
}
public void display(GLAutoDrawable drawable)
{
GL gl = drawable.getGL();
//
gl.glClear(GL.GL_COLOR_BUFFER_BIT);
gl.glColor4f(1.0f, 1.0f, 0.0f, 0.75f);
gl.glRectf(0.0f, 0.0f, 0.5f, 1.0f);
gl.glColor4f(0.0f, 1.0f, 1.0f, 0.75f);
gl.glRectf(0.0f, 0.0f, 1.f, 0.5f);
/* draw colored polygons in reverse order in upper right */
gl.glColor4f(0.f, 1.0f, 1.0f, 0.75f);
gl.glRectf(0.5f, 0.5f, 1.0f, 1.0f);
gl.glColor4f(1.0f, 1.0f, 0.0f, 0.75f);
gl.glRectf(0.5f, 0.5f, 1.0f, 1.0f);
gl.glEnd();
}
public void reshape(GLAutoDrawable drawable, int x, int y, int w, int h)
{
GL gl = drawable.getGL();
GLU glu = new GLU();
gl.glViewport(0, 0, w, h);
gl.glMatrixMode(GL.GL_PROJECTION);
gl.glLoadIdentity();
if (w <= h) glu.gluOrtho2D(0.0, 1.0, 0.0, 1.0 * h / w);
else glu.gluOrtho2D(0.0, 1.0 * w / h, 0.0, 1.0);
gl.glMatrixMode(GL.GL_MODELVIEW);
}
public void displayChanged(GLAutoDrawable drawable, boolean modeChanged,
boolean deviceChanged)
{
}
public void keyTyped(KeyEvent key)
{
}
public void keyPressed(KeyEvent key)
{
switch (key.getKeyCode()) {
case KeyEvent.VK_ESCAPE:
System.exit(0);
break;
default:
break;
}
}
public void keyReleased(KeyEvent key)
{
}
}
|
Other API Tips 
You can share your information about this topic using the form below!
Please do not post your questions with this form! Thanks.