If I make the following small change to the "draw a torus" example of using jogl with GLCanvas, it mostly works, but the redrawing of the window seems to be unreliable. It will occasionally flicker or turn into a gray window. Is something like this supposed to work?
package mil.navy.nrl.itd.woodchuck;
import javax.media.opengl.GLContext;
import javax.media.opengl.GLDrawableFactory;
import javax.media.opengl.glu.GLU;
import org.eclipse.swt.SWT;
import org.eclipse.swt.events.PaintListener;
import org.eclipse.swt.events.PaintEvent;
import org.eclipse.swt.graphics.Rectangle;
import org.eclipse.swt.layout.FillLayout;
import org.eclipse.swt.opengl.GLCanvas;
import org.eclipse.swt.opengl.GLData;
import org.eclipse.swt.widgets.Composite;
import org.eclipse.swt.widgets.Display;
import org.eclipse.swt.widgets.Event;
import org.eclipse.swt.widgets.Listener;
import org.eclipse.swt.widgets.Shell;
/**
* Created on Jun 19, 2009 @ 4:14:11 PM.
*
* @author brandon-enochs
*/
public class SwtJoglSample {
// --------------------------- main() method ---------------------------
public static void main(String[] args) {
final Display display = new Display();
Shell shell = new Shell(display);
shell.setLayout(new FillLayout());
Composite comp = new Composite(shell, SWT.NONE);
comp.setLayout(new FillLayout());
GLData data = "" GLData();
data.doubleBuffer = true;
final GLCanvas canvas = new GLCanvas(comp, SWT.NONE, data);
canvas.setCurrent();
final GLContext context = GLDrawableFactory.getFactory().createExternalGLContext();
canvas.addListener(
SWT.Resize, new Listener() {
public void handleEvent(Event event) {
Rectangle bounds = canvas.getBounds();
float fAspect = (float) bounds.width / (float) bounds.height;
canvas.setCurrent();
context.makeCurrent();
GL gl = context.getGL();
gl.glViewport(0, 0, bounds.width, bounds.height);
gl.glMatrixMode(GL.GL_PROJECTION);
gl.glLoadIdentity();
GLU glu = new GLU();
glu.gluPerspective(45.0f, fAspect, 0.5f, 400.0f);
gl.glMatrixMode(GL.GL_MODELVIEW);
gl.glLoadIdentity();
context.release();
}
}
);
context.makeCurrent();
GL gl = context.getGL();
gl.glClearColor(1.0f, 1.0f, 1.0f, 1.0f);
gl.glColor3f(1.0f, 0.0f, 0.0f);
gl.glHint(GL.GL_PERSPECTIVE_CORRECTION_HINT, GL.GL_NICEST);
gl.glClearDepth(1.0);
gl.glLineWidth(2);
gl.glEnable(GL.GL_DEPTH_TEST);
context.release();
shell.setText("SWT/JOGL Example");
shell.setSize(640, 480);
shell.open();
// First change here, move from running display.asynchExec to using a paintListener
canvas.addPaintListener(
new PaintListener() {
int rot = 0;
@Override
public void paintControl(PaintEvent e) {
if (!canvas.isDisposed()) {
canvas.setCurrent();
context.makeCurrent();
GL gl = context.getGL();
gl.glClear(GL.GL_COLOR_BUFFER_BIT | GL.GL_DEPTH_BUFFER_BIT);
gl.glClearColor(.3f, .5f, .8f, 1.0f);
gl.glLoadIdentity();
gl.glTranslatef(0.0f, 0.0f, -10.0f);
float frot = rot;
gl.glRotatef(0.15f * rot, 2.0f * frot, 10.0f * frot, 1.0f);
gl.glRotatef(0.3f * rot, 3.0f * frot, 1.0f * frot, 1.0f);
rot++;
gl.glPolygonMode(GL.GL_FRONT_AND_BACK, GL.GL_LINE);
gl.glColor3f(0.9f, 0.9f, 0.9f);
drawTorus(gl, 1, 1.9f + ((float) Math.sin((0.004f * frot))), 15, 15);
canvas.swapBuffers();
context.release();
}
}
}
);
// Without this, paint events were never fired unless the screen was resized
display.asyncExec(new Runnable() {
@Override
public void run() {
canvas.redraw();
display.asyncExec(this);
}
});
while (!shell.isDisposed()) {
if (!display.readAndDispatch()) {
display.sleep();
}
}
display.dispose();
}
static void drawTorus(GL gl, float r, float R, int nsides, int rings) {
float ringDelta = 2.0f * (float) Math.PI / rings;
float sideDelta = 2.0f * (float) Math.PI / nsides;
float theta = 0.0f, cosTheta = 1.0f, sinTheta = 0.0f;
for (int i = rings - 1; i >= 0; i--) {
float theta1 = theta + ringDelta;
float cosTheta1 = (float) Math.cos(theta1);
float sinTheta1 = (float) Math.sin(theta1);
gl.glBegin(GL.GL_QUAD_STRIP);
float phi = 0.0f;
for (int j = nsides; j >= 0; j--) {
phi += sideDelta;
float cosPhi = (float) Math.cos(phi);
float sinPhi = (float) Math.sin(phi);
float dist = R + r * cosPhi;
gl.glNormal3f(cosTheta1 * cosPhi, -sinTheta1 * cosPhi, sinPhi);
gl.glVertex3f(cosTheta1 * dist, -sinTheta1 * dist, r * sinPhi);
gl.glNormal3f(cosTheta * cosPhi, -sinTheta * cosPhi, sinPhi);
gl.glVertex3f(cosTheta * dist, -sinTheta * dist, r * sinPhi);
}
gl.glEnd();
theta = theta1;
cosTheta = cosTheta1;
sinTheta = sinTheta1;
}
}
}
-- Aaron
