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/*******************************************************************************
* Copyright (c) 2000, 2010 IBM Corporation and others.
* All rights reserved. This program and the accompanying materials
* are made available under the terms of the Eclipse Public License v1.0
* which accompanies this distribution, and is available at
* http://www.eclipse.org/legal/epl-v10.html
*
* Contributors:
* IBM Corporation - initial API and implementation
*******************************************************************************/
package org.eclipse.swt.snippets;
/*
* SWT OpenGL snippet: capture a LWJGL drawing to an SWT Image
*
* This example is essentially Snippet195 with the capture() method
* added. It should be easily adaptable to other OpenGL packages.
*
* For a list of all SWT example snippets see
* http://www.eclipse.org/swt/snippets/
*
* @since 3.2
*/
import java.nio.ByteBuffer;
import org.eclipse.swt.*;
import org.eclipse.swt.layout.*;
import org.eclipse.swt.widgets.*;
import org.eclipse.swt.graphics.*;
import org.eclipse.swt.opengl.GLCanvas;
import org.eclipse.swt.opengl.GLData;
import org.lwjgl.opengl.GL11;
import org.lwjgl.opengl.GLContext;
import org.lwjgl.util.glu.GLU;
import org.lwjgl.LWJGLException;
public class Snippet341 {
static void drawTorus(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);
GL11.glBegin(GL11.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;
GL11.glNormal3f(cosTheta1 * cosPhi, -sinTheta1 * cosPhi, sinPhi);
GL11.glVertex3f(cosTheta1 * dist, -sinTheta1 * dist, r * sinPhi);
GL11.glNormal3f(cosTheta * cosPhi, -sinTheta * cosPhi, sinPhi);
GL11.glVertex3f(cosTheta * dist, -sinTheta * dist, r * sinPhi);
}
GL11.glEnd();
theta = theta1;
cosTheta = cosTheta1;
sinTheta = sinTheta1;
}
}
public static void main(String [] args) {
final Display display = new Display();
Shell shell = new Shell(display);
shell.setLayout(new GridLayout());
GLData data = new GLData ();
data.doubleBuffer = true;
final GLCanvas canvas = new GLCanvas(shell, SWT.NONE, data);
canvas.setLayoutData(new GridData(640,480));
canvas.setCurrent();
try {
GLContext.useContext(canvas);
} catch(LWJGLException e) { e.printStackTrace(); }
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();
try {
GLContext.useContext(canvas);
} catch(LWJGLException e) { e.printStackTrace(); }
GL11.glViewport(0, 0, bounds.width, bounds.height);
GL11.glMatrixMode(GL11.GL_PROJECTION);
GL11.glLoadIdentity();
GLU.gluPerspective(45.0f, fAspect, 0.5f, 400.0f);
GL11.glMatrixMode(GL11.GL_MODELVIEW);
GL11.glLoadIdentity();
}
});
GL11.glClearColor(1.0f, 1.0f, 1.0f, 1.0f);
GL11.glColor3f(1.0f, 0.0f, 0.0f);
GL11.glHint(GL11.GL_PERSPECTIVE_CORRECTION_HINT, GL11.GL_NICEST);
GL11.glClearDepth(1.0);
GL11.glLineWidth(2);
GL11.glEnable(GL11.GL_DEPTH_TEST);
Button button = new Button(shell, SWT.PUSH);
button.setText("Capture");
button.addListener(SWT.Selection, new Listener() {
public void handleEvent(Event event) {
capture(canvas);
}
});
shell.pack();
shell.open();
display.asyncExec(new Runnable() {
int rot = 0;
public void run() {
if (!canvas.isDisposed()) {
canvas.setCurrent();
try {
GLContext.useContext(canvas);
} catch(LWJGLException e) { e.printStackTrace(); }
GL11.glClear(GL11.GL_COLOR_BUFFER_BIT | GL11.GL_DEPTH_BUFFER_BIT);
GL11.glClearColor(.3f, .5f, .8f, 1.0f);
GL11.glLoadIdentity();
GL11.glTranslatef(0.0f, 0.0f, -10.0f);
float frot = rot;
GL11.glRotatef(0.15f * rot, 2.0f * frot, 10.0f * frot, 1.0f);
GL11.glRotatef(0.3f * rot, 3.0f * frot, 1.0f * frot, 1.0f);
rot++;
GL11.glPolygonMode(GL11.GL_FRONT_AND_BACK, GL11.GL_LINE);
GL11.glColor3f(0.9f, 0.9f, 0.9f);
drawTorus(1, 1.9f + ((float) Math.sin((0.004f * frot))), 15, 15);
canvas.swapBuffers();
display.asyncExec(this);
}
}
});
while (!shell.isDisposed()) {
if (!display.readAndDispatch())
display.sleep();
}
display.dispose();
}
static void capture(GLCanvas glCanvas) {
final int PAD = 4;
Display display = glCanvas.getDisplay();
Rectangle bounds = glCanvas.getBounds();
int size = bounds.width * PAD * bounds.height;
ByteBuffer buffer = ByteBuffer.allocateDirect(size);
GL11.glReadPixels(0, 0, bounds.width, bounds.height, GL11.GL_RGBA, GL11.GL_UNSIGNED_BYTE, buffer);
byte[] bytes = new byte[size];
buffer.get(bytes);
/*
* In OpenGL (0,0) is at the bottom-left corner, and y values ascend in the upward
* direction. This is opposite to SWT which defines (0,0) to be at the top-left
* corner with y values ascendingin the downwards direction. Re-order the OpenGL-
* provided bytes to SWT's expected order so that the Image will not appear inverted.
*/
byte[] temp = new byte[bytes.length];
for (int i = 0; i < bytes.length; i += bounds.width * PAD) {
System.arraycopy(bytes, bytes.length - i - bounds.width * PAD, temp, i, bounds.width * PAD);
}
bytes = temp;
ImageData data = new ImageData(bounds.width, bounds.height, 32, new PaletteData(0xFF000000, 0xFF0000, 0xFF00), PAD, bytes);
final Image image = new Image(display, data);
Shell shell = new Shell(display);
shell.setLayout(new GridLayout());
Canvas canvas = new Canvas(shell, SWT.NONE);
canvas.setLayoutData(new GridData(bounds.width, bounds.height));
canvas.addListener(SWT.Paint, new Listener() {
public void handleEvent(Event event) {
event.gc.drawImage(image, 0, 0);
}
});
shell.pack();
shell.open();
shell.addListener(SWT.Dispose, new Listener() {
public void handleEvent(Event event) {
image.dispose();
}
});
}
}
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