procanvas.java

立方体透视投影绘图程序

package pjt;

import java.awt.*;
import java.awt.event.MouseEvent;

public class ProCanvas extends Canvas implements Runnable{
	
	private static final long serialVersionUID = 1L;
	int cx, cy, cz;
	double[] px, py, pz;
	int[] gx, gy;
	boolean bStart;
	Cube c;
	
	public void setPlace(int x, int y, int z) {
		cx = x;
		cy = y;
		cz = z;
	}
	
	public void setPoint(double[] x, double[] y, double[] z) {
		this.px = x;
		this.py = y;
		this.pz = z;
	}
	
	public void project() {
		gx = new int[9];
		gy = new int[9];
		for (int i=1; i<9; i++) {
			gx[i] = 300 + (int)(cx + (px[i]-cx)*cz/(cz-pz[i]));
			gy[i] = 250 - (int)(cy + (py[i]-cy)*cz/(cz-pz[i]));
		}
	}
	
	public void paint(Graphics g) {
		if (gx != null) {
			for(int i=1; i<4; i++) {
				g.drawLine(gx[i], gy[i], gx[i+1], gy[i+1]);
				g.drawLine(gx[i], gy[i], gx[i+4], gy[i+4]);
				g.drawLine(gx[i+4], gy[i+4], gx[i+5], gy[i+5]);
			}
			g.drawLine(gx[4], gy[4], gx[1], gy[1]);
			g.drawLine(gx[4], gy[4], gx[8], gy[8]);
			g.drawLine(gx[5], gy[5], gx[8], gy[8]);
		}
	}
	
	public ProCanvas() {
		enableEvents(AWTEvent.MOUSE_EVENT_MASK);
	}
	
	protected void processMouseEvent (MouseEvent e) {
		if (e.getID() == MouseEvent.MOUSE_PRESSED) {
			bStart = true;
			new Thread(this).start();
		}
		else if (e.getID() == MouseEvent.MOUSE_RELEASED) {
			bStart = false;
		}
		
	}
	
	public void run() {
		c.setTheta(1);
		while (bStart) {
			try {
				Thread.sleep(250);
				c.whirl();
				project();
				repaint();
			}
			catch(Exception e) {
				e.printStackTrace();
			}
		}
	}
}