package org.eclipse.swt.snippets;


import org.eclipse.opengl.GL;
import org.eclipse.opengl.GLU;
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;


public class EXP_SWT {
    
    static long startTime = System.currentTimeMillis() + 5000;
    static long fps = 0;
    
    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);
            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;
        }
    }

    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();

        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();
                GL.glViewport(0, 0, bounds.width, bounds.height);
                GL.glMatrixMode(GL.GL_PROJECTION);
                GL.glLoadIdentity();
                GLU.gluPerspective(45.0f, fAspect, 0.5f, 400.0f);
                GL.glMatrixMode(GL.GL_MODELVIEW);
                GL.glLoadIdentity();
            }
        });

        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);

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

        display.asyncExec(new Runnable() {
            int rot = 0;
            public void run() {
                if (!canvas.isDisposed()) {
                    canvas.setCurrent();
                    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(1, 1.9f + ((float) Math.sin((0.004f * frot))), 15, 15);
                    canvas.swapBuffers();
                    if (startTime > System.currentTimeMillis()) {
                        fps++;
                    } else {
                        long timeUsed = 5000 + (startTime - System
                                .currentTimeMillis());
                        startTime = System.currentTimeMillis() + 5000;
                        System.out.println(fps + " frames in "
                                + (float) (timeUsed / 1000f) + " seconds = "
                                + (fps / (timeUsed / 1000f)));
                        fps = 0;
                    }
                    
                    display.asyncExec(this);
                }
            }
        });

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