用processing画李萨如曲线

李萨如曲线

有没有对示波器上变化曲线产生过兴趣，它叫做李萨如曲线：

数学上，利萨茹(Lissajous)曲线（又称利萨茹图形、李萨如图形或鲍迪奇(Bowditch)曲线）是两个沿着互相垂直方向的正弦振动的合成的轨迹

（参见http://zh.wikipedia.org/wiki/%E5%88%A9%E8%90%A8%E8%8C%B9%E6%9B%B2%E7%BA%BF）

代码

   1: //int n=4;

   2: int p=17;

   3: int q=15;

   4:  

   5: int a = displayWidth /2 ;

   6: int b = a;//displayHeight /2 ;

   7:  

   8: int radius = 2;

   9: float miu = 0;//PI / 2 / p;

  10: float miu_max = TWO_PI;

  11: float miu_delta = miu_max / 100;

  12:  

  13: public void setup() {

  14:   size(displayWidth, displayHeight);

  15:   background(0);

  16:   frameRate(2);

  17:   

  18:   a = displayWidth / 5 ;

  19:   b = a ;

  20: }

  21:  

  22: public void draw() {  

  23:  

  24:     miu += miu_delta;

  25:     if (miu >= miu_max)

  26:         miu = 0;

  27: //    if (miu >= miu_max)

  28: //    {

  29: //        miu_delta = -miu_delta;

  30: //        miu += miu_delta;

  31: //    }

  32: //    else if (miu < 0)

  33: //    {

  34: //        miu_delta = -miu_delta;

  35: //        miu += miu_delta;

  36: //    }

  37:     

  38:     fill(0,0,0,250);

  39:     rect(-1,-1, displayWidth+1, displayHeight+1);

  40:     

  41:     int last_x = -1;

  42:     int last_y = -1;

  43:     

  44:     for (float theta=0;theta<TWO_PI;theta+=TWO_PI/360)

  45:     {

  46:         int x = (int) (a * sin(p * theta)) + displayWidth /2;

  47:         int y = (int) (b * sin(q * theta + (miu))) + displayHeight /2;

  48:         

  49:         colorMode(HSB, 255);

  50:         stroke(90, 255, 255);

  51:         fill(90, 255, 255);

  52:         

  53:         if (last_x != -1 >> last_y != -1)

  54:         {

  55:             line(last_x, last_y, x, y);

  56:             line(last_x-1, last_y, x-1, y);

  57:         }

  58:         

  59:         last_x = x;

  60:         last_y = y;

  61:  

  62:         //ellipse(x, y, radius, radius);

  63:     }

  64:     

  65: }

截图