Using OpenGL in Matlab with Java?

Question

In Matlab I have

import javax.media.opengl.GL;

How do I now use OpenGL? Can anyone provide a very small sample?

Please note: If this wasnt in Matlab then it would be easy. But the question specifically relates to using this in Matlab.

Answer 1

MATLAB comes with the JOGL 1.x libraries available on its static classpath, so it's a matter of compiling your source code (with those JAR files on the classpath), then running the program inside MATLAB.

Below is a "hello world" OpenGL example in Java. I show how to compile and run it directly from inside MATLAB:

HelloWorld.java

import java.awt.Frame;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;

import javax.media.opengl.GL;
import javax.media.opengl.GLAutoDrawable;
import javax.media.opengl.GLCanvas;
import javax.media.opengl.GLEventListener;

public class HelloWorld implements GLEventListener {

    public static void main(String[] args) {
        Frame frame = new Frame("JOGL HelloWorld");
        GLCanvas canvas = new GLCanvas();
        canvas.addGLEventListener(new HelloWorld());
        frame.add(canvas);
        frame.setSize(300, 300);
        frame.setVisible(true);
        frame.addWindowListener(new WindowAdapter() {
            public void windowClosing(WindowEvent e) {
                System.exit(0);
            }
        });
    }

    public void display(GLAutoDrawable drawable) {
        GL gl = drawable.getGL();
        gl.glClearColor(0.0f, 0.0f, 0.0f, 0.0f);
        gl.glClear(GL.GL_COLOR_BUFFER_BIT);
        gl.glColor3f(1.0f, 1.0f, 1.0f);
        gl.glOrtho(-1.0, 1.0, -1.0, 1.0, -1.0, 1.0);

        gl.glBegin(GL.GL_POLYGON);
        gl.glVertex2f(-0.5f, -0.5f);
        gl.glVertex2f(-0.5f, 0.5f);
        gl.glVertex2f(0.5f, 0.5f);
        gl.glVertex2f(0.5f, -0.5f);
        gl.glEnd();

        gl.glFlush();
    }

    public void init(GLAutoDrawable drawable) {
    }
    public void reshape(GLAutoDrawable drawable, 
        int x, int y, int width, int height) {
    }
    public void displayChanged(GLAutoDrawable drawable, 
        boolean modeChanged, boolean deviceChanged) {
    }
}

HelloWorld_compile_run.m

%# compile the Java code
jPath = fullfile(matlabroot,'java','jarext',computer('arch'));
cp = [fullfile(jPath,'jogl.jar') pathsep fullfile(jPath,'gluegen-rt.jar')];
cmd = ['javac -cp "' cp '" HelloWorld.java'];
system(cmd,'-echo')
javaaddpath(pwd)

%# run it
javaMethodEDT('main','HelloWorld','')

You could try calling Java commands directly in MATLAB (as @DarkByte has shown), but at some point, you have to handle OpenGL events by implementing GLEventListener interface methods: init, display, reshape, etc.. As you can't define Java classes directly in MATLAB, you might as well write the whole thing in Java as I did.