connect jGL with SWT GLCanvas

jzy3d-emul-gl-swt/pom.xml

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+<project xmlns="http://maven.apache.org/POM/4.0.0"
+	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+	xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
+	<modelVersion>4.0.0</modelVersion>
+	<parent>
+		<groupId>org.jzy3d</groupId>
+		<artifactId>jzy3d-all</artifactId>
+		<version>2.0.1-SNAPSHOT</version>
+	</parent>
+	<artifactId>jzy3d-emul-gl-swt</artifactId>
+	<name>Jzy3d EmulGL Implementation for SWT with jGL</name>
+	<properties>
+		<swt-version>3.116.100</swt-version>
+	</properties>
+	<dependencies>
+		<dependency>
+			<groupId>org.eclipse.platform</groupId>
+			<artifactId>org.eclipse.swt.gtk.linux.x86_64</artifactId>
+			<version>${swt-version}</version>
+			<exclusions>
+				<exclusion>
+					<groupId>org.eclipse.platform</groupId>
+					<artifactId>org.eclipse.swt</artifactId>
+				</exclusion>
+			</exclusions>
+		</dependency>
+		<dependency>
+			<groupId>org.jzy3d</groupId>
+			<artifactId>jGL</artifactId>
+			<version>${project.version}</version>
+		</dependency>
+	</dependencies>
+</project>
+

jzy3d-emul-gl-swt/src/main/java/org/jzy3d/swt/JGLCanvas.java

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+/*******************************************************************************
+ * (c) 2021 Läubisoft GmbH, Christoph Läubrich
+ * 
+ * This library is free software; you can redistribute it and/or modify it under the terms of the
+ * GNU Lesser General Public License as published by the Free Software Foundation; either version
+ * 2.1 of the License, or any later version. the GNU Lesser General Public License should be
+ * included with this distribution in the file LICENSE.
+ * 
+ * This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without
+ * even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ */
+package org.jzy3d.swt;
+
+import org.eclipse.swt.SWT;
+import org.eclipse.swt.events.ControlEvent;
+import org.eclipse.swt.events.ControlListener;
+import org.eclipse.swt.graphics.GC;
+import org.eclipse.swt.graphics.Image;
+import org.eclipse.swt.graphics.ImageData;
+import org.eclipse.swt.graphics.PaletteData;
+import org.eclipse.swt.graphics.Point;
+import org.eclipse.swt.opengl.GLCanvas;
+import org.eclipse.swt.opengl.GLData;
+import org.eclipse.swt.widgets.Composite;
+
+import jgl.GL;
+
+public class JGLCanvas extends GLCanvas {
+
+	protected GL gl = new SWTGL();
+
+	public JGLCanvas(Composite parent, int style, GLData data) {
+
+		super(parent, style, data);
+		gl.setAutoAdaptToHiDPI(false);
+		doResize(0, 0);
+		addControlListener(new ControlListener() {
+
+			@Override
+			public void controlResized(ControlEvent e) {
+
+				Point size = getSize();
+				doResize(size.x, size.y);
+			}
+
+
+			@Override
+			public void controlMoved(ControlEvent e) {
+
+			}
+		});
+		addPaintListener(e -> {
+			doPaint(e.gc);
+		});
+	}
+
+	protected void doResize(int w, int h) {
+
+		gl.glViewport(0, 0, w, h);
+	}
+
+	protected void doPaint(GC gc) {
+
+		gc.setBackground(getBackground());
+		Point size = getSize();
+		gc.fillRectangle(0, 0, size.x, size.y);
+		gc.setForeground(gc.getDevice().getSystemColor(SWT.COLOR_RED));
+		gc.drawLine(0, 0, size.x, size.y);
+		SWTGL swtgl = (SWTGL)gl;
+		if(swtgl.imageData != null) {
+			Image image = new Image(gc.getDevice(), swtgl.imageData);
+			gc.drawImage(image, 0, 0);
+			image.dispose();
+		}
+		System.out.println("paint done");
+	}
+
+	public GL getGL() {
+
+		return gl;
+	}
+
+	@Override
+	public void setCurrent() {
+
+		super.setCurrent();
+	}
+
+	private static final class SWTGL extends GL {
+
+		private ImageData imageData;
+
+		@Override
+		public void glFlush() {
+
+			int[] buffer = Context.ColorBuffer.Buffer;
+			int width = Context.Viewport.Width;
+			int height = Context.Viewport.Height;
+			PaletteData palette = new PaletteData(0xFF0000, 0xFF00, 0xFF);
+			imageData = new ImageData(width, height, 24, palette);
+			imageData.setPixels(0, 0, buffer.length, buffer, 0);
+			byte[] alphaBytes = new byte[buffer.length];
+			for(int i = 0; i < alphaBytes.length; i++) {
+				alphaBytes[i] = (byte)((buffer[i] >> 24) & 0xFF);
+			}
+			imageData.setAlphas(0, 0, alphaBytes.length, alphaBytes, 0);
+		}
+	}
+}

jzy3d-emul-gl-swt/src/test/java/org/jzy3d/swt/SWTTest.java

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+/*******************************************************************************
+ * Copyright (c) 2021 Läubisoft GmbH and others.
+ *
+ * This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License 2.0
+ * which accompanies this distribution, and is available at
+ * https://www.eclipse.org/legal/epl-2.0/
+ *
+ * SPDX-License-Identifier: EPL-2.0
+ *
+ * Contributors:
+ * Christoph Läubrich - initial API and implementation
+ *******************************************************************************/
+package org.jzy3d.swt;
+
+import org.eclipse.swt.SWT;
+import org.eclipse.swt.layout.FillLayout;
+import org.eclipse.swt.opengl.GLData;
+import org.eclipse.swt.widgets.Display;
+import org.eclipse.swt.widgets.Shell;
+
+public class SWTTest {
+
+	public static void main(String[] args) {
+
+		Display display = new Display();
+		Shell shell = new Shell(display);
+		shell.setText("jGL Canvas Test");
+		shell.setLayout(new FillLayout());
+		shell.open();
+		GLData data = new GLData();
+		data.doubleBuffer = true;
+		JGLCanvas canvas = new bezcurve(shell, SWT.NONE, data);
+		canvas.setCurrent();
+		while(!shell.isDisposed()) {
+			if(!display.readAndDispatch()) {
+				display.sleep();
+			}
+		}
+		display.dispose();
+	}
+}

jzy3d-emul-gl-swt/src/test/java/org/jzy3d/swt/bezcurve.java

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+package org.jzy3d.swt;
+/*
+ * bezcurve.java This program uses evaluators to draw a Bezier curve.
+ */
+
+import org.eclipse.swt.graphics.GC;
+import org.eclipse.swt.opengl.GLData;
+import org.eclipse.swt.widgets.Composite;
+
+import jgl.GL;
+
+public class bezcurve extends JGLCanvas {
+
+	public bezcurve(Composite parent, int style, GLData data) {
+
+		super(parent, style, data);
+		myinit();
+	}
+
+	private static final float ctrlpoints[][] = {{-4.0f, -4.0f, 0.0f}, {-2.0f, 4.0f, 0.0f}, {2.0f, -4.0f, 0.0f}, {4.0f, 4.0f, 0.0f}};
+
+	private void myinit() {
+
+		gl.glClearColor(0.0f, 0.0f, 0.0f, 1.0f);
+		gl.glShadeModel(GL.GL_FLAT);
+		gl.glMap1f(GL.GL_MAP1_VERTEX_3, 0.0f, 1.0f, 3, 4, ctrlpoints);
+		gl.glEnable(GL.GL_MAP1_VERTEX_3);
+	}
+
+	@Override
+	protected void doPaint(GC gc) {
+
+		int i;
+		gl.glClear(GL.GL_COLOR_BUFFER_BIT);
+		gl.glColor3f(1.0f, 1.0f, 1.0f);
+		gl.glBegin(GL.GL_LINE_STRIP);
+		for(i = 0; i <= 30; i++)
+			gl.glEvalCoord1f(i / 30.0f);
+		gl.glEnd();
+		/* The following code displays the control points as dots. */
+		gl.glPointSize(5.0f);
+		gl.glColor3f(1.0f, 1.0f, 0.0f);
+		gl.glBegin(GL.GL_POINTS);
+		for(i = 0; i < 4; i++)
+			gl.glVertex3fv(ctrlpoints[i]);
+		gl.glEnd();
+		gl.glFlush();
+		super.doPaint(gc);
+	}
+
+	@Override
+	protected void doResize(int w, int h) {
+
+		gl.glViewport(0, 0, w, h);
+		gl.glMatrixMode(GL.GL_PROJECTION);
+		gl.glLoadIdentity();
+		if(w <= h) {
+			gl.glOrtho(-5.0f, 5.0f, -5.0f * h / w, 5.0f * h / w, -5.0f, 5.0f);
+		} else {
+			gl.glOrtho(-5.0f * w / h, 5.0f * w / h, -5.0f, 5.0f, -5.0f, 5.0f);
+		}
+		gl.glMatrixMode(GL.GL_MODELVIEW);
+		gl.glLoadIdentity();
+	}
+
+
+}