CVector [] points;
int numPoints = 10;
void setup()
{
  size(150,150);

  points = new CVector[numPoints];
  for (int i=0;i<numPoints;i++)
  {
    points[i] = new CVector();
    points[i].m_x = random(1.0f)*width;
    points[i].m_y = random(1.0f)*height;
  }

  numPoints=3;

  colorMode(RGB, 250);

}

void mousePressed()
{
  for (int i=0;i<numPoints;i++)
  {
    points[i].m_x = random(1.0f)*width;
    points[i].m_y = random(1.0f)*height;
  }
}

void keyPressed()
{
  if (key=='1')
  {
    numPoints=1;
    mousePressed();
  }
  if (key=='2')
  {
    numPoints=2;
    mousePressed();
  }
  if (key=='3')
  {
    numPoints=3;
    mousePressed();
  }
  if (key=='4')
  {
    numPoints=4;
    mousePressed();
  }
  if (key=='5')
  {
    numPoints=5;
    mousePressed();
  }

}

void loop()
{

  CVector tempVector = new CVector();
  CVector totalVector = new CVector();

  points[0].m_x = mouseX;
  points[0].m_y = mouseY;

  int x,y,i;
  for (y=0;y<height;y++)
  {
    for (x=0;x<width;x++)
    {
      tempVector.set(0,0);
      totalVector.set(0,0);

      for (i=0;i<numPoints;i++)
      {
        tempVector.m_x = x - points[i].m_x;
        tempVector.m_y = y - points[i].m_y;
        tempVector.normalise();
        totalVector.add(tempVector);
      }
      totalVector.normalise();

      stroke((totalVector.m_x+1.0f)*120.0f,(totalVector.m_y+1.0f)*120.0f,100.0f);
      point(x,y);

    }
  }

}

class CVector
{
  // Construction & destruction.
CVector() { m_x=0; m_y=0; }
CVector(float x, float y) { set(x,y); }

void set( float x, float y) { m_x=x; m_y=y; }
float getLengthSquared( ) { return (m_x*m_x)+(m_y*m_y); }
float getLength( ) { return sqrt((m_x*m_x)+(m_y*m_y)); }
void add( CVector rhs ) { m_x+=rhs.m_x; m_y+=rhs.m_y; }
void subtract( CVector rhs ) { m_x-=rhs.m_x; m_y-=rhs.m_y; };
void multiply( float rhs ) { m_x*=rhs; m_y*=rhs; };
void setFromAngle( float angle) { m_x = sin(angle); m_y = cos(angle); }
  float normalise( )
  {
    float Length = getLength();
    if (Length<0.001f) Length=0.001f;
    m_x/=Length;
    m_y/=Length;
    return Length;
  }

  // Members
  float m_x;
  float m_y;
}