Arrow.java

import java.awt.Color;
import java.awt.Graphics2D;

/**
 * 
 * Represents a single arrow that moves down the screen
 *
 * @author Ryan_Tai,David_Choi
 * @version May 11, 2020
 * @author Period: 1
 * @author Assignment: RhythmGame
 *
 * @author Sources: None
 */
public class Arrow {
	private int yPos;
	private static final int YVEL = 5;
	private static final int SHIFT = 50;
	private static Color green = new Color(75, 210, 80);
	private static Color red = new Color(195, 30, 30);
	private static Color yellow = new Color(215, 210, 15);
	private static Color blue = new Color(33, 160, 210);
	private ArrowLane lane;

	/**
	 * Creates an arrow in the given arrow lane
	 * 
	 * @param al the arrow lane the arrow is in
	 */
	public Arrow(ArrowLane al) {
		yPos = -SHIFT;
		lane = al;
	}

	/**
	 * 
	 * Moves the arrow by its velocity and removes it if its off the screen
	 */
	public void move() {
		yPos += YVEL;
		if (yPos > RhythmGame.getScreenHeight()) {
			lane.remove();
		}
	}

	/**
	 * 
	 * Draws the arrow on the screen
	 * 
	 * @param g2  the 2D graphics of the screen
	 * @param dir the direction of the arrow
	 */
	public void draw(Graphics2D g2, Direction dir) {
		int x = lane.getX();
		switch (dir) {
		case DOWN:
			int[] xcoor = { x - SHIFT, x, x + SHIFT };
			int[] ycoor = { yPos - SHIFT, yPos + SHIFT, yPos - SHIFT };
			g2.setColor(green);
			g2.fillPolygon(xcoor, ycoor, 3);
			g2.setColor(Color.black);
			g2.drawPolygon(xcoor, ycoor, 3);
			break;
		case LEFT:
			int[] xcoor1 = { x - SHIFT, x + SHIFT, x + SHIFT };
			int[] ycoor1 = { yPos, yPos - SHIFT, yPos + SHIFT };
			g2.setColor(red);
			g2.fillPolygon(xcoor1, ycoor1, 3);
			g2.setColor(Color.black);
			g2.drawPolygon(xcoor1, ycoor1, 3);
			break;
		case RIGHT:
			int[] xcoor2 = { x + SHIFT, x - SHIFT, x - SHIFT };
			int[] ycoor2 = { yPos, yPos + SHIFT, yPos - SHIFT };
			g2.setColor(yellow);
			g2.fillPolygon(xcoor2, ycoor2, 3);
			g2.setColor(Color.black);
			g2.drawPolygon(xcoor2, ycoor2, 3);
			break;
		case UP:
			int[] xcoor3 = { x - SHIFT, x, x + SHIFT };
			int[] ycoor3 = { yPos + SHIFT, yPos - SHIFT, yPos + SHIFT };
			g2.setColor(blue);
			g2.fillPolygon(xcoor3, ycoor3, 3);
			g2.setColor(Color.black);
			g2.drawPolygon(xcoor3, ycoor3, 3);
			break;
		default:
			return;
		}
		;

	}

	/**
	 * 
	 * returns the current height of the arrow
	 * 
	 * @return the y position of the arrow
	 */
	public int getY() {
		return yPos;
	}

	/**
	 * 
	 * Returns the half height of the arrow
	 * 
	 * @return half of the arrow's height
	 */
	public static int getHalfHeight() {
		return SHIFT;
	}
}