public void recur(Graphics g, double x1, double x2, double y1, double y2, int range) {
?? ??? ??? ?double x3 = (x1 + x2) / 2;
?? ??? ??? ?double y3 = (y1 + y2) / 2;
?? ??? ??? ?if (x2-x1<= 15) {
?? ??? ??? ??? ?g.drawLine((int) x1, (int) y1, (int) x3, (int) y3);
?? ??? ??? ??? ?g.drawLine((int) x2, (int) y2, (int) x3, (int) y3);
?? ??? ??? ??? ?return;
?? ??? ??? ?}
?? ??? ??? ?Random rand=new Random();
?? ??? ??? ?int num=rand.nextInt(range);
?? ??? ??? ?recur(g, x1, x3, y1, y3-num, range);
?? ??? ??? ?recur(g, x3, x2, y3-num, y2, range);?? ??? ??? ??? ??? ?
?? ??? ?}

最終效果如下

很明顯這并不像山脈背景吧，然后我通過(guò)查閱相關(guān)資料了解到問(wèn)題在于需要每次遞歸時(shí)需要將縱坐標(biāo)隨機(jī)數(shù)值減小，改進(jìn)后代碼如下

public void recur(Graphics g, double x1, double x2, double y1, double y2, int range) {
//range我用的是300，大家可以自己調(diào)節(jié)
?? ??? ??? ?double x3 = (x1 + x2) / 2;
?? ??? ??? ?double y3 = (y1 + y2) / 2;
?? ??? ??? ?if (x2-x1<= 1|range==0) {
?? ??? ??? ??? ?g.drawLine((int) x1, (int) y1, (int) x3, (int) y3);
?? ??? ??? ??? ?g.drawLine((int) x2, (int) y2, (int) x3, (int) y3);
?? ??? ??? ??? ?return;
?? ??? ??? ?}
?? ??? ??? ?Random rand=new Random();
?? ??? ??? ?int num=rand.nextInt(range*2)-range;
?? ??? ??? ?range*=0.5;
?? ??? ??? ?recur(g, x1, x3, y1, y3+num, range);
?? ??? ??? ?recur(g, x3, x2, y3+num, y2, range);?? ??? ??? ??? ??? ?
?? ??? ?}

效果很接近山脈

然后我又想可以使用Polygon類來(lái)對(duì)山脈進(jìn)行顏色填充，同時(shí)傳入不同的透明度進(jìn)行不同山脈的區(qū)別一定更美觀，廢話不多說(shuō)，上代碼

public void recur(Graphics g, double x1, double x2, double y1, double y2, int range,int alp) {
? ? ? ? //實(shí)例range用的是300
? ? ? ? //四座山脈透明度分別為220，180，120，40
?? ??? ?double x3 = (x1 + x2) / 2;
?? ??? ?double y3 = (y1 + y2) / 2;
?? ??? ?if (x2-x1<= 1|range==0) {
?? ??? ??? ?g.drawLine((int) x1, (int) y1, (int) x3, (int) y3);
?? ??? ??? ?g.drawLine((int) x2, (int) y2, (int) x3, (int) y3);
?? ??? ??? ?Polygon p=new Polygon();
?? ??? ??? ?p.addPoint((int)x3, (int)y3);
?? ??? ??? ?p.addPoint((int)x1, (int)y1);
?? ??? ??? ?p.addPoint((int)x1, 800);
?? ??? ??? ?p.addPoint((int)x2, 800);
?? ??? ??? ?p.addPoint((int)x2, (int)y2);
?? ??? ??? ?g.setColor(new Color(0,0,0,alp));
?? ??? ??? ?g.fillPolygon(p);
?? ??? ??? ?return;
?? ??? ?}
?? ??? ?Random rand=new Random();
?? ??? ?int num=rand.nextInt(range*2)-range;
?? ??? ?range*=0.5;
? ? ? ? //上面的0.5也可以改變，他控制的是循環(huán)次數(shù)和山脈的陡峭度，大家可以改變嘗試
?? ??? ?recur(g, x1, x3, y1, y3+num, range,alp);
?? ??? ?recur(g, x3, x2, y3+num, y2, range,alp);
?? ?}