自由落下　1

自由落下.java

import processing.core.*;

public class JiyuuRakka extends PApplet{
	Ball b1;
	
	public void setup(){
		size(200, 200);
		b1 = new Ball(random(width), random(0,20));
		b1.setHeight(height);
	}
	
	public void draw(){
		background(100);
		b1.update();
		
		ellipse(b1.x, b1.y, 10, 10);
	}
}

public class Ball {
	private
		float _x, _y;
		float _speedy;
		float _size = 5;

		int _height;
		int _i;
		float g = (float)0.009;
		
	public
		float x, y;
	
		
	Ball(float x, float y){
		_x = x;
		_y = y;
		_i = 0;
	}
	
	public void setHeight(int h) {
		_height = h;
	}
	
	public void update(){
		_i++;
		_y = _y + g * _i * _i / 2;
		_speedy = g * _i;
		x = _x;
		y = _y;
	}
}