Notes

package cse423lab2;
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import javax.media.opengl.GL2;
import javax.media.opengl.GLAutoDrawable;
import javax.media.opengl.GLEventListener;
import javax.media.opengl.glu.GLU;

/**
*
* @author sbiswas.amit
*/
public class DDALines implements GLEventListener {
/**
* Interface to the GLU library.
*/
private GLU glu;

/**
* Take care of initialization here.
* @param gld
*/
@Override
public void init(GLAutoDrawable gld) {
GL2 gl = gld.getGL().getGL2();
glu = new GLU();

gl.glClearColor(0.0f, 0.0f, 0.0f, 1.0f);
gl.glViewport(-250, -150, 250, 150);
gl.glMatrixMode(GL2.GL_PROJECTION);
gl.glLoadIdentity();
glu.gluOrtho2D(-250.0, 250.0, -150.0, 150.0);
}

/**
* Take care of drawing here.
* @param drawable
*/
@Override
public void display(GLAutoDrawable drawable) {
GL2 gl = drawable.getGL().getGL2();

gl.glClear(GL2.GL_COLOR_BUFFER_BIT);
/*
* put your code here
*/
DDA(gl, 0.0f, 0.0f, 0.0f, 50.0f);
DDA(gl, 0.0f, 50.0f, 50.0f, 0.0f);
DDA(gl, 0.0f, 0.0f, 50.0f, 0.0f);

}

@Override
public void reshape(GLAutoDrawable drawable, int x, int y, int width, int height) {
//do nothing
}

public void displayChanged(GLAutoDrawable drawable, boolean modeChanged, boolean deviceChanged) {
//do nothing
}

private void DDA(GL2 gl, float x1, float y1, float x2, float y2) {
//write your own code


gl.glPointSize(1.0f);
gl.glColor3d(1, 0, 0);
gl.glBegin(GL2.GL_POINTS);


gl.glVertex2f(x1, y1);

float len;
float xc,yc;
float dy = y2-y1;
float dx = x2-x1;
float m = dy/dx;
float adx = Math.abs(dx);
float ady = Math.abs(dy);

if(adx>=ady) {
len = adx;
} else {
len = ady;
}

dx = dx/len;
dy = dy/len;

xc = x1 + 0.5f*Sign(dx);
yc = y1 + 0.5f*Sign(dy);

int i=0;
while(i<=len) {
gl.glVertex2f(xc, yc);
xc = xc+dx;
yc = yc+dy;
i++;
}


gl.glVertex2f(x2, y2);
gl.glEnd();
}

public int Sign(float x) {
if(x<0) {
return -1;
} else if(x==0) {
return 0;
} else {
return 1;
}
}

public void dispose(GLAutoDrawable arg0) {
//do nothing
}
}

package cse423lab2;

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//com.jogamp or javax.media
import javax.media.opengl.GLCapabilities;
import javax.media.opengl.GLProfile;
import javax.media.opengl.awt.GLCanvas;
import javax.swing.JFrame;
/**
*
* @author sbiswas.amit
*/
public class OpenGL {

/**
* uses point drawing DDA algorithm
**/
/*public static void main(String[] args) {
//getting the capabilities object of GL2 profile
final GLProfile profile=GLProfile.get(GLProfile.GL2);
GLCapabilities capabilities=new GLCapabilities(profile);
// The canvas
final GLCanvas glcanvas=new GLCanvas(capabilities);
ThirdGLEventListener b =new ThirdGLEventListener();
glcanvas.addGLEventListener(b);
glcanvas.setSize(400, 400);
//creating frame
final JFrame frame = new JFrame("My frame");
//adding canvas to frame
frame.add(glcanvas);
//frame.setSize(640,480);
frame.setSize(frame.getContentPane().getPreferredSize());
frame.setVisible(true);
}*/

/**
* uses line drawing method
**/
public static void main(String[] args) {

//getting the capabilities object of GL2 profile
final GLProfile profile = GLProfile.get(GLProfile.GL2);
GLCapabilities capabilities = new GLCapabilities(profile);

// The canvas
final GLCanvas glcanvas = new GLCanvas(capabilities);
DDALines drawing = new DDALines();
glcanvas.addGLEventListener(drawing);
glcanvas.setSize(400, 400);

//creating frame
final JFrame frame = new JFrame ("straight Line");

//adding canvas to frame
frame.getContentPane().add(glcanvas);
frame.setSize(frame.getContentPane().getPreferredSize());
frame.setVisible(true);

}

}