org.eclipse.swt.snippets.Snippet195.java Source code

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Here is the source code for org.eclipse.swt.snippets.Snippet195.java

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/*******************************************************************************
 * Copyright (c) 2000, 2019 IBM Corporation 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:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.swt.snippets;

/*
 * SWT OpenGL snippet: use LWJGL to draw to an SWT GLCanvas
 *
 * For a list of all SWT example snippets see
 * http://www.eclipse.org/swt/snippets/
 *
 * @since 3.2
 */
import org.eclipse.swt.*;
import org.eclipse.swt.graphics.*;
import org.eclipse.swt.layout.*;
import org.eclipse.swt.opengl.*;
import org.eclipse.swt.widgets.*;
import org.lwjgl.opengl.*;

public class Snippet195 {
    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 FillLayout());
        Composite comp = new Composite(shell, SWT.NONE);
        comp.setLayout(new FillLayout());
        GLData data = new GLData();
        data.doubleBuffer = true;
        final GLCanvas canvas = new GLCanvas(comp, SWT.NONE, data);

        canvas.setCurrent();
        GL.createCapabilities();

        canvas.addListener(SWT.Resize, event -> {
            Rectangle bounds = canvas.getBounds();
            float fAspect = (float) bounds.width / (float) bounds.height;
            canvas.setCurrent();
            GL.createCapabilities();
            GL11.glViewport(0, 0, bounds.width, bounds.height);
            GL11.glMatrixMode(GL11.GL_PROJECTION);
            GL11.glLoadIdentity();
            float near = 0.5f;
            float bottom = -near * (float) Math.tan(45.f / 2);
            float left = fAspect * bottom;
            GL11.glFrustum(left, -left, bottom, -bottom, near, 400.f);
            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);

        shell.setText("SWT/LWJGL Example");
        shell.setSize(640, 480);
        shell.open();

        final Runnable run = new Runnable() {
            int rot = 0;

            @Override
            public void run() {
                if (!canvas.isDisposed()) {
                    canvas.setCurrent();
                    GL.createCapabilities();
                    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);
                }
            }
        };
        canvas.addListener(SWT.Paint, event -> run.run());
        display.asyncExec(run);

        while (!shell.isDisposed()) {
            if (!display.readAndDispatch())
                display.sleep();
        }
        display.dispose();
    }
}