draw a rotating torus using the LWJGL OpenGL binding : OpenGL « SWT JFace Eclipse « Java






draw a rotating torus using the LWJGL OpenGL binding

/*******************************************************************************
 * Copyright (c) 2000, 2005 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: 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.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.opengl.glu.GLU;
import org.lwjgl.LWJGLException;

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();
    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);

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

           
       








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