package graphics;
public class BezierCurve
{
  protected Spline spline;
  protected double[] G;

  //characteristic matrix
  protected final static double[][] charMatrixData =
  {
    {-1,    3,   -3,    1},
    { 3,   -6,    3,    0},
    {-3,    3,    0,    0},
    { 1,    0,    0,    0}
  };
  protected final static Matrix3D charMatrix = new Matrix3D(charMatrixData);

  public BezierCurve(double p1, double p2, double p3, double p4)
  {
    double[] C = new double[4]; //a,b,c,d

    G = new double[4]; //ctrl points
    G[0] = p1; G[1] = p2; G[2] = p3; G[3] = p4;

    charMatrix.transform(G, C);
//System.err.println(C[0] +" "+ C[1] +" "+ C[2] +" "+ C[3]);
    spline = new Spline(C[0], C[1], C[2], C[3]);
  }

  public double get(double t)
  {
    return spline.get(t);
  }

  public Spline getSpline()
  {
    return spline;
  }

  public void dump()
  {
    System.err.println("Dumping spline points:");
    System.err.println("("+ G[0] +", "+ G[1] +", "+ G[2] +", "+ G[3] +")");
  }
}