class Anchors
{
    Anchors()
    {
        points = new PParticle[NUM_ANCHOR_POINTS];
        for (int i = 0; i < points.length; i++)
        {
            points[i] = new PParticle(random(0, width - 10), random(0, height - 10), physics);  
            points[i].particle.makeFixed();
        }
        selectedPoint = null;        
    }
    
    void render()
    {
        noStroke();
        fill(10, 10, 200);
        for (int i = 0; i < points.length; i++)
            ellipse(points[i].x, points[i].y, 10, 10);
        noFill();
    }
 
    boolean selectPoint(float x, float y, float r)
    {
        selectedPoint = null;
        PVector p = new PVector(x, y);
        for (int i = 0; i < points.length; i++)
            if (points[i].dist(p) < r)
            {
                selectedPoint = points[i];
                return true;
            }    
        return false;      
    }    
    
    void setSelectedPoint(float x, float y)
    {
        if (selectedPoint != null)
        {
            selectedPoint.moveTo(x, y);
        }
    }    
    
    int getAnchorIndex(PVector p, float r)
    {
        for (int i = 0; i < points.length; i++)
            if (points[i].dist(p) < r) return i;
        return -1;
    }
    
    void clear()
    {
        for (int i = 0; i < points.length; i++) points[i].restart(physics);
    }
          
    void displaceX()
    {
        for (int i = 0; i < points.length; i++)
        {
            float x = points[i].x + 0.5;
            if (width < x) x = 0;
            else if (x < 0) x = width;
            points[i].moveTo(x, points[i].y);
        }
    }
    
    void displaceY()
    {
        for (int i = 0; i < points.length; i++)
        {
            float y = points[i].y + 0.5;
            if (width < y) y = 0;
            else if (y < 0) y = height;
            points[i].moveTo(points[i].x, y);
        }
    }

    void rotateAroundScreenCenter()
    {
        float c = cos(0.001);
        float s = sin(0.001);            
      
        for (int i = 0; i < points.length; i++)
        {
            float x = points[i].x - 0.5 * width;
            float y = points[i].y - 0.5 * height;          

            float newx = c * x + s * y;
            float newy = -s * x + c * y;

            points[i].moveTo(newx + 0.5 * width, newy + 0.5 * height);
        }
    }
    
    PParticle[] points;
    PParticle selectedPoint;
}