package jp.nyatla.nyartoolkit.core;

/**
 * get_vertex関数を切り離すためのクラス
 * 
 */
final public class NyARVertexCounter
{
	public final int[] vertex = new int[10];// 6まで削れる

	public int number_of_vertex;

	private double thresh;

	private int[] x_coord;

	private int[] y_coord;

	public boolean getVertex(int[] i_x_coord, int[] i_y_coord, int st, int ed, double i_thresh)
	{
		this.number_of_vertex = 0;
		this.thresh = i_thresh;
		this.x_coord = i_x_coord;
		this.y_coord = i_y_coord;
		return get_vertex(st, ed);
	}

	/**
	 * static int get_vertex( int x_coord[], int y_coord[], int st, int ed,double thresh, int vertex[], int *vnum) 関数の代替関数
	 * 
	 * @param x_coord
	 * @param y_coord
	 * @param st
	 * @param ed
	 * @param thresh
	 * @return
	 */
	private boolean get_vertex(int st, int ed)
	{
		//メモ:座標値は65536を超えなければint32で扱って大丈夫なので変更。
		//dmaxは4乗なのでやるとしてもint64じゃないとマズイ
		int v1 = 0;
		final int[] lx_coord = this.x_coord;
		final int[] ly_coord = this.y_coord;
		final int a = ly_coord[ed] - ly_coord[st];
		final int b = lx_coord[st] - lx_coord[ed];
		final int c = lx_coord[ed] * ly_coord[st] - ly_coord[ed] * lx_coord[st];
		double dmax = 0;
		for (int i = st + 1; i < ed; i++) {
			final double d = a * lx_coord[i] + b * ly_coord[i] + c;
			if (d * d > dmax) {
				dmax = d * d;
				v1 = i;
			}
		}
		if (dmax / (double)(a * a + b * b) > thresh) {
			if (!get_vertex(st, v1)) {
				return false;
			}
			if (number_of_vertex > 5) {
				return false;
			}
			vertex[number_of_vertex] = v1;// vertex[(*vnum)] = v1;
			number_of_vertex++;// (*vnum)++;

			if (!get_vertex(v1, ed)) {
				return false;
			}
		}
		return true;
	}
}