threed.java

源代码使用说明 本书全部代码全部在JDK中调试成功

import java.applet.Applet;
import java.awt.Graphics;
import java.awt.Color;
import java.awt.Event;
import java.io.StreamTokenizer;
import java.io.InputStream;
import java.io.IOException;
import java.net.URL;

class FileFormatException extends Exception {
    public FileFormatException(String s) {
	super(s);
    }
}

/** The representation of a 3D model */
class Model3D {
    float vert[];
    int tvert[];
    int nvert, maxvert;
    int con[];
    int ncon, maxcon;
    boolean transformed;
    Matrix3D mat;

    float xmin, xmax, ymin, ymax, zmin, zmax;

    Model3D () {
	mat = new Matrix3D ();
	mat.xrot(20);
	mat.yrot(30);
    }
    /** Create a 3D model by parsing an input stream */
    Model3D (InputStream is) throws IOException, FileFormatException {
	this();
	StreamTokenizer st = new StreamTokenizer(is);
	st.eolIsSignificant(true);
	st.commentChar('#');
scan:
	while (true) {
	    switch (st.nextToken()) {
	      default:
		break scan;
	      case StreamTokenizer.TT_EOL:
		break;
	      case StreamTokenizer.TT_WORD:
		if ("v".equals(st.sval)) {
		    double x = 0, y = 0, z = 0;
		    if (st.nextToken() == StreamTokenizer.TT_NUMBER) {
			x = st.nval;
			if (st.nextToken() == StreamTokenizer.TT_NUMBER) {
			    y = st.nval;
			    if (st.nextToken() == StreamTokenizer.TT_NUMBER)
				z = st.nval;
			}
		    }
		    addVert((float) x, (float) y, (float) z);
		    while (st.ttype != StreamTokenizer.TT_EOL &&
			    st.ttype != StreamTokenizer.TT_EOF)
			st.nextToken();
		} else if ("f".equals(st.sval) || "fo".equals(st.sval) || "l".equals(st.sval)) {
		    int start = -1;
		    int prev = -1;
		    int n = -1;
		    while (true)
			if (st.nextToken() == StreamTokenizer.TT_NUMBER) {
			    n = (int) st.nval;
			    if (prev >= 0)
				add(prev - 1, n - 1);
			    if (start < 0)
				start = n;
			    prev = n;
			} else if (st.ttype == '/')
			    st.nextToken();
			else
			    break;
		    if (start >= 0)
			add(start - 1, prev - 1);
		    if (st.ttype != StreamTokenizer.TT_EOL)
			break scan;
		} else {
		    while (st.nextToken() != StreamTokenizer.TT_EOL
			    && st.ttype != StreamTokenizer.TT_EOF);
		}
	    }
	}
	is.close();
	if (st.ttype != StreamTokenizer.TT_EOF)
	    throw new FileFormatException(st.toString());
    }

    /** Add a vertex to this model */
    int addVert(float x, float y, float z) {
	int i = nvert;
	if (i >= maxvert)
	    if (vert == null) {
		maxvert = 100;
		vert = new float[maxvert * 3];
	    } else {
		maxvert *= 2;
		float nv[] = new float[maxvert * 3];
		System.arraycopy(vert, 0, nv, 0, vert.length);
		vert = nv;
	    }
	i *= 3;
	vert[i] = x;
	vert[i + 1] = y;
	vert[i + 2] = z;
	return nvert++;
    }
    /** Add a line from vertex p1 to vertex p2 */
    void add(int p1, int p2) {
	int i = ncon;
	if (p1 >= nvert || p2 >= nvert)
	    return;
	if (i >= maxcon)
	    if (con == null) {
		maxcon = 100;
		con = new int[maxcon];
	    } else {
		maxcon *= 2;
		int nv[] = new int[maxcon];
		System.arraycopy(con, 0, nv, 0, con.length);
		con = nv;
	    }
	if (p1 > p2) {
	    int t = p1;
	    p1 = p2;
	    p2 = t;
	}
	con[i] = (p1 << 16) | p2;
	ncon = i + 1;
    }
    /** Transform all the points in this model */
    void transform() {
	if (transformed || nvert <= 0)
	    return;
	if (tvert == null || tvert.length < nvert * 3)
	    tvert = new int[nvert*3];
	mat.transform(vert, tvert, nvert);
	transformed = true;
    }

    private void sort(int lo0, int hi0) {
	int a[] = con;
	int lo = lo0;
	int hi = hi0;
	if (lo >= hi)
	    return;
	int mid = a[(lo + hi) / 2];
	while (lo < hi) {
	    while (lo < hi && a[lo] < mid) {
		lo++;
	    }
	    while (lo < hi && a[hi] >= mid) {
		hi--;
	    }
	    if (lo < hi) {
		int T = a[lo];
		a[lo] = a[hi];
		a[hi] = T;
	    }
	}
	if (hi < lo) {
	    int T = hi;
	    hi = lo;
	    lo = T;
	}
	sort(lo0, lo);
	sort(lo == lo0 ? lo + 1 : lo, hi0);
    }

    /** eliminate duplicate lines */
    void compress() {
	int limit = ncon;
	int c[] = con;
	sort(0, ncon - 1);
	int d = 0;
	int pp1 = -1;
	for (int i = 0; i < limit; i++) {
	    int p1 = c[i];
	    if (pp1 != p1) {
		c[d] = p1;
		d++;
	    }
	    pp1 = p1;
	}
	ncon = d;
    }

    static Color gr[];

    /** Paint this model to a graphics context.  It uses the matrix associated
	with this model to map from model space to screen space.
	The next version of the browser should have double buffering,
	which will make this *much* nicer */
    void paint(Graphics g) {
	if (vert == null || nvert <= 0)
	    return;
	transform();
	if (gr == null) {
	    gr = new Color[16];
	    for (int i = 0; i < 16; i++) {
		int grey = (int) (170*(1-Math.pow(i/15.0, 2.3)));
		gr[i] = new Color(grey, grey, grey);
	    }
	}
	int lg = 0;
	int lim = ncon;
	int c[] = con;
	int v[] = tvert;
	if (lim <= 0 || nvert <= 0)
	    return;
	for (int i = 0; i < lim; i++) {
	    int T = c[i];
	    int p1 = ((T >> 16) & 0xFFFF) * 3;
	    int p2 = (T & 0xFFFF) * 3;
	    int grey = v[p1 + 2] + v[p2 + 2];
	    if (grey < 0)
		grey = 0;
	    if (grey > 15)
		grey = 15;
	    if (grey != lg) {
		lg = grey;
		g.setColor(gr[grey]);
	    }
	    g.drawLine(v[p1], v[p1 + 1],
		       v[p2], v[p2 + 1]);
	}
    }

    /** Find the bounding box of this model */
    void findBB() {
	if (nvert <= 0)
	    return;
	float v[] = vert;
	float xmin = v[0], xmax = xmin;
	float ymin = v[1], ymax = ymin;
	float zmin = v[2], zmax = zmin;
	for (int i = nvert * 3; (i -= 3) > 0;) {
	    float x = v[i];
	    if (x < xmin)
		xmin = x;
	    if (x > xmax)
		xmax = x;
	    float y = v[i + 1];
	    if (y < ymin)
		ymin = y;
	    if (y > ymax)
		ymax = y;
	    float z = v[i + 2];
	    if (z < zmin)
		zmin = z;
	    if (z > zmax)
		zmax = z;
	}
	this.xmax = xmax;
	this.xmin = xmin;
	this.ymax = ymax;
	this.ymin = ymin;
	this.zmax = zmax;
	this.zmin = zmin;
    }
}

/** An applet to put a 3D model into a page */
public class ThreeD extends Applet implements Runnable {
    Model3D md;
    boolean painted = true;
    float xfac;
    int prevx, prevy;
    float xtheta, ytheta;
    float scalefudge = 1;
    Matrix3D amat = new Matrix3D(), tmat = new Matrix3D();
    String mdname = null;
    String message = null;

    public void init() {
	System.out.println("at init time, CM = "+getColorModel());
	mdname = getParameter("model");
	try {
	    scalefudge = Float.valueOf(getParameter("scale")).floatValue();
	}catch(Exception e){};
	amat.yrot(20);
	amat.xrot(20);
	if (mdname == null)
	    mdname = "model.obj";
	resize(size().width <= 20 ? 400 : size().width,
	       size().height <= 20 ? 400 : size().height);
    }
    public void run() {
	InputStream is = null;
	try {
	    Thread.currentThread().setPriority(Thread.MIN_PRIORITY);
	    is = new URL(getDocumentBase(), mdname).openStream();
	    Model3D m = new Model3D (is);
	    md = m;
	    m.findBB();
	    m.compress();
	    float xw = m.xmax - m.xmin;
	    float yw = m.ymax - m.ymin;
	    float zw = m.zmax - m.zmin;
	    if (yw > xw)
		xw = yw;
	    if (zw > xw)
		xw = zw;
	    float f1 = size().width / xw;
	    float f2 = size().height / xw;
	    xfac = 0.7f * (f1 < f2 ? f1 : f2) * scalefudge;
	} catch(Exception e) {
	    md = null;
	    message = e.toString();
	}
	try {
	    if (is != null)
		is.close();
	} catch(Exception e) {
	}
	repaint();
    }
    public void start() {
	if (md == null && message == null)
	    new Thread(this).start();
    }
    public void stop() {
    }
    public boolean mouseDown(Event e, int x, int y) {
	prevx = x;
	prevy = y;
	return true;
    }
    public boolean mouseDrag(Event e, int x, int y) {
	tmat.unit();
	float xtheta = (prevy - y) * 360.0f / size().width;
	float ytheta = (x - prevx) * 360.0f / size().height;
	tmat.xrot(xtheta);
	tmat.yrot(ytheta);
	amat.mult(tmat);
	if (painted) {
	    painted = false;
	    repaint();
	}
	prevx = x;
	prevy = y;
	return true;
    }
    public void paint(Graphics g) {
	//System.out.println("at paint time, CM = "+getColorModel());
	if (md != null) {
	    md.mat.unit();
	    md.mat.translate(-(md.xmin + md.xmax) / 2,
			     -(md.ymin + md.ymax) / 2,
			     -(md.zmin + md.zmax) / 2);
	    md.mat.mult(amat);
//	    md.mat.scale(xfac, -xfac, 8 * xfac / size().width);
	    md.mat.scale(xfac, -xfac, 16 * xfac / size().width);
	    md.mat.translate(size().width / 2, size().height / 2, 8);
	    md.transformed = false;
	    md.paint(g);
	    setPainted();
	} else if (message != null) {
	    g.drawString("Error in model:", 3, 20);
	    g.drawString(message, 10, 40);
	}
    }
    private synchronized void setPainted() {
	painted = true;
	notifyAll();
    }
//    private synchronized void waitPainted() {
//	while (!painted)
//	    wait();
//	painted = false;
//    }
}