Hi,
I’m trying to prepare my project for the Graphics course: drawing a superellipsoid and supertoroid in wireframe form. The problem is, I could not see anything on my canvas although I’m drawing something. I suspect the problem is the perspective projection I’m using, but I could not figure it out. Any help?
Thanks 
import java.awt.BorderLayout;
import java.awt.Dimension;
import javax.media.opengl.GL;
import javax.media.opengl.GLAutoDrawable;
import javax.media.opengl.GLCanvas;
import javax.media.opengl.GLCapabilities;
import javax.media.opengl.GLEventListener;
import javax.media.opengl.glu.GLU;
import javax.swing.JFrame;
public class Canvas extends JFrame implements GLEventListener
{
private static final long serialVersionUID = 1L;
private static final int CANVAS_WIDTH = 800;
private static final int CANVAS_HEIGHT = 600;
// Dimension of the transformation canvas
private static final Dimension DEFAULT_CANVAS_SIZE =
new Dimension(CANVAS_WIDTH, CANVAS_HEIGHT);
// Canvas to add to the frame
private GLCanvas canvas;
// Constructor
public Canvas()
{
super("CS 465 - Programming Assignment 2");
GLCapabilities capabilities = new GLCapabilities();
capabilities.setDoubleBuffered(true);
canvas = new GLCanvas(capabilities);
canvas.addGLEventListener(this);
canvas.setSize(DEFAULT_CANVAS_SIZE);
// Add required listeners
this.setDefaultCloseOperation(EXIT_ON_CLOSE);
this.add(canvas, BorderLayout.CENTER);
}
public void init(GLAutoDrawable drawable)
{
final GL gl = drawable.getGL();
final GLU glu = new GLU();
// Set canvas color to white
gl.glClearColor(1.0f, 1.0f, 1.0f, 1.0f);
gl.glClearDepth(1.0f);
gl.glEnable(GL.GL_DEPTH_TEST);
gl.glDepthFunc(GL.GL_LEQUAL);
gl.glHint(GL.GL_PERSPECTIVE_CORRECTION_HINT, GL.GL_NICEST);
gl.glMatrixMode(GL.GL_PROJECTION);
gl.glLoadIdentity();
glu.gluPerspective(45.0f, 1, 0.1f, 100.0f);
gl.glMatrixMode(GL.GL_MODELVIEW);
gl.glLoadIdentity();
gl.glViewport(0, 0, CANVAS_WIDTH, CANVAS_HEIGHT);
}
public void display(GLAutoDrawable drawable)
{
final GL gl = drawable.getGL();
SuperEllipsoid test = new SuperEllipsoid(1, 1, 1, 1, 1, 50, 50);
test.draw(gl);
}
// Called when the display window is resized
public void reshape(GLAutoDrawable drawable, int x, int y, int width, int height)
{
// do nothing...
}
// Called when the display mode has changed
public void displayChanged(GLAutoDrawable drawable, boolean w, boolean arg2)
{
// do nothing...
}
public static void main(String[] args)
{
Canvas canvas = new Canvas();
canvas.pack();
canvas.setResizable(false);
canvas.setVisible(true);
}
}
The draw code I’m using…
public void draw(GL gl) {
float U, dU, V, dV;
float S, dS, T, dT;
dU = (u2 - u1) / (float) uSeg;
dV = (v2 - v1) / (float) vSeg;
dS = (s2 - s1) / (float) uSeg;
dT = (t2 - t1) / (float) vSeg;
U = u1;
S = s1;
gl.glPolygonMode(GL.GL_FRONT_AND_BACK, GL.GL_LINE);
gl.glBegin(GL.GL_QUADS);
for (int y = 0; y < uSeg; y++) {
V = v1;
T = t1;
for (int x = 0; x < vSeg; x++) {
// Vertex 1
EllipsoidNormal tmp = sqEllipsoid(1, 1, 1, U, V, n, e);
gl.glNormal3f(tmp.nx, tmp.ny, tmp.nz);
gl.glTexCoord2f(S, T);
gl.glVertex3f(tmp.x, tmp.y, tmp.z);
// Vertex 2
tmp = sqEllipsoid(1, 1, 1, U + dU, V, n, e);
gl.glNormal3f(tmp.nx, tmp.ny, tmp.nz);
gl.glTexCoord2f(S + dS, T);
gl.glVertex3f(tmp.x, tmp.y, tmp.z);
// Vertex 3
tmp = sqEllipsoid(1, 1, 1, U + dU, V + dV, n, e);
gl.glNormal3f(tmp.nx, tmp.ny, tmp.nz);
gl.glTexCoord2f(S + dS, T + dT);
gl.glVertex3f(tmp.x, tmp.y, tmp.z);
// Vertex 4
tmp = sqEllipsoid(1, 1, 1, U, V + dV, n, e);
gl.glNormal3f(tmp.nx, tmp.ny, tmp.nz);
gl.glTexCoord2f(S, T + dT);
gl.glVertex3f(tmp.x, tmp.y, tmp.z);
// Update variables for next loop */
V += dV;
T += dT;
}
// Update variables for next loop */
S += dS;
U += dU;
}
gl.glEnd();
}