[gl4java-usergroup] Different Orientation in GLJPanel and GLCanvas

[<NM...@th...>]

Hi,

I've recently managed to get the GLJPanel displaying on my system(Win 2000.
JDK 1.3.1). I've noticed, however, that there is a weird error occurring
regarding axis orientation. I may be missing something but it seems as
though the Y axis is correct in GLCanvas but is inverted when the same
world is rendered in GLJPanel. Odd error. I've included an example below
that illustrates the issues.

STEP 1:
The code below will originally launch an Internal Frame containing a
GLCanvas. In the canvas I draw 3 cones, a Red pointing out towards us along
the Positive Z Axis, a Blue one pointing down the positive X Axis and a
Green one pointing up the Positive Y Axis.

STEP 2:
If you then go into the code and ONLY:

(SEE COMMENTS IN CODE TOO)
Uncomment lines : 16, 23
Comment lines : 13, 78

STEP 3:
and recompile you will then see the same example but this time with a
GLJPanel in the internal frame. The example is in all other cases
identical. In this case all axis are the same except that the Y Axis, the
Green Cone, is now pointing in the opposite direction.

Obviously a JPanel and a Canvas should not produce different orientation.
Am I not setting something correctly? Or is this a bug?

Thanks in advance for your help,
Noah Keen

HERE IS THE EXAMPLE CODE :


import javax.swing.*;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;


import gl4java.*;
import gl4java.awt.*;
import gl4java.utils.glut.*;
import gl4java.swing.*;
/*** COMMENT THE LINE BELOW TO RUN GLJPANEL *****/
public class GLCanvasTest extends GLCanvas {

/***  UNCOMMENT THIS TO RUN GLJPANEL ********/
//public class GLCanvasTest extends GLJPanel {

    public GLCanvasTest() {

        super(200, 200);

        /*** UNCOMMENT  BELOW TO RUN GLJPANEL ****/
        //super();

    }

    /**
     * Sets up all basic OpenGL parameters. Adds lights and sets default
material.
     **/
    public void init() {
        gl.glShadeModel(GL_SMOOTH);
        gl.glEnable(GL_LIGHTING);
        gl.glClearColor(0.0f, 0.0f, 0.0f, 0.0f);

        gl.glEnable(GL_LIGHT1);
        float ambient[] = {0.2f, 0.2f, 0.2f, 0.0f};
        float diffuse[] = {0.6f, 0.6f, 0.6f, 0.0f};
        float specular[] = {1.0f, 1.0f, 1.0f, 0.0f};
        float position[] = {1.0f, 1.0f, 1.0f, 0.0f};
        gl.glLightfv(GL_LIGHT1, GL_AMBIENT, ambient);
        gl.glLightfv(GL_LIGHT1, GL_DIFFUSE, diffuse);
        gl.glLightfv(GL_LIGHT1, GL_SPECULAR, specular);
        gl.glLightfv(GL_LIGHT1, GL_POSITION, position);

        gl.glPolygonMode(GL_FRONT_AND_BACK, GL_FILL);
        gl.glEnable(GL_NORMALIZE);

        // init the projection and ModelView matrix
        gl.glMatrixMode(GL_PROJECTION);
        gl.glLoadIdentity();
        gl.glMatrixMode(GL_MODELVIEW);
        gl.glLoadIdentity();


    }

    /**
     * Rotates, translates and displays the world
     **/
    public void display() {

        /* Standard GL4Java Init */
        if ( cvsIsInit()==false || glj.gljMakeCurrent() == false ) {
            return;
        }

        // clear old
        gl.glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

        //draw
        drawAxis();

        // a GL4Java necessity
        glj.gljSwap();


        /*** COMMENT THE LINE BELOW TO RUN GLJPANEL *****/
        glj.gljFree();

    }


    /**
     * Empty. For simplicity
     **/
    public void reshape(int width, int height) {

    }


    /**
     * Draws three arrows on the X, Y and Z axis.
     * A cone which points from the origin to the POS plane of the axis
     *
     * NOTE!!!! - glu.gluCylinder() by default draws from the origin along
     *            the POS Z axis.
     *
     **/
    private void drawAxis() {

        float red[] = {1.0f, 0.0f, 0.0f, 0.0f};
        float green[] = {0.0f, 1.0f, 0.0f, 0.0f};
        float blue[] = {0.0f, 0.0f, 1.0f, 0.0f};

        // draw a GREEN Y axis
        gl.glPushMatrix();
        gl.glRotatef(-90.0f, 1.0f, 0.0f, 0.0f);
        gl.glMaterialfv(GL_FRONT_AND_BACK, GL_AMBIENT_AND_DIFFUSE, green);
        glu.gluCylinder(glu.gluNewQuadric(), 0.05f, 0.0f, 0.5f, 5, 5);
        gl.glPopMatrix();

        // draw a GREEN Y axis
        gl.glPushMatrix();
        gl.glRotatef(90.0f, 0.0f, 1.0f, 0.0f);
        gl.glMaterialfv(GL_FRONT_AND_BACK, GL_AMBIENT_AND_DIFFUSE, blue);
        glu.gluCylinder(glu.gluNewQuadric(), 0.05f, 0.0f, 0.5f, 5, 5);
        gl.glPopMatrix();

        // draw a RED Z AXIS
        gl.glMaterialfv(GL_FRONT_AND_BACK, GL_AMBIENT_AND_DIFFUSE, red);
        glu.gluCylinder(glu.gluNewQuadric(), 0.05f, 0.0f, 0.5f, 5, 5);

    }

     static GLCanvasTest canvas;
    public static void main(String[] args) {
        JFrame frame = new JFrame("Test");
        JDesktopPane desktop = new JDesktopPane();
        JInternalFrame iFrame = new JInternalFrame("Test", true, true,
true, true);
        canvas = new GLCanvasTest();

        frame.setSize(300,300);
        iFrame.setSize(200, 200);
        iFrame.setVisible(true);
        iFrame.getContentPane().add(canvas);
        desktop.add(iFrame);
        iFrame.getContentPane().add(canvas);

        frame.getContentPane().add(desktop);

        desktop.setVisible(true);

        frame.setVisible(true);

        frame.addWindowListener(new WindowAdapter() {
                public void windowClosing(WindowEvent e) {
                         canvas.cvsDispose();
                    System.exit(0);
                }
                });

    }

}