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.
2 Answers
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.
4 Comments
twerdster
Nice answer. Thanks. I was hoping this would give me some way to access the underlying z buffer of a Matlab figure but I cant see how. I asked that in another question here: stackoverflow.com/questions/5963193/…
Ben Voigt
@twerdster: Yes, that's a very different question.
twerdster
@Ben Voigt, I dont fully agree. I think the only way to access the buffer is using a method similar to the one Amro has just described so its at least related. Ive added the link to my comment now.
Amro
I don't think that's quite possible, though you could create a separate question, maybe someone has a different idea. BTW, I did show in a previous answer how to simulate a "drawing canvas" using an image...
Some info from this link:
- In matlab, you do not need to type "new"--objects are created as needed.
- In matlab, you use 'single quotes' where you use "double quotes" in java.
- In java you call a routine with no inputs by putting () after its name. This is unnecessary in matlab.
Little example:
import javax.swing.*
J = JFrame('Hi there')
L = JLabel('A Label');
P = J.getContentPane
P.add(L)
J.setSize(200,200);
J.setVisible(1)
And please check here for the MathWorks documentation.
1 Comment
twerdster
Unfortunately this doesnt help me with OpenGL
importis java keyword not matlab