Computer Science 252
Problem Solving with Java
Spring 2014, The College of Saint Rose
WindyFallingSnow Demo
A working demo of WindyFallingSnow will appear below. Click inside the applet to interact with it.
WindyFallingSnow BlueJ Project
Click here to download a BlueJ project for WindyFallingSnow.
WindyFallingSnow Source Code
The Java source code for WindyFallingSnow is below. Click on a file name to download it.
import objectdraw.*;
import java.awt.*;
/*
*
* Example FallingSnow: the snowflakes that fall, but now with their
* x speeds determined by the current wind speed, provided by a Wind
* object.
*
* Jim Teresco, Siena College, CSIS 120, Spring 2011
* The College of Saint Rose, Fall 2013, Fall 2014
* Based on example from CSCI 134, Williams College
*
* $Id: FallingSnow.java 2452 2014-10-13 15:59:20Z terescoj $
*/
public class FallingSnow extends ActiveObject {
// delay between snow motions
private static final int DELAY_TIME = 33;
private DrawingCanvas canvas;
// speed of fall
private double ySpeed;
// the snowflake
private VisibleImage snow;
// the wind, which is responsible for providing a current
// wind speed on demand
private Wind wind;
// initialize the instance variables and start the active object
public FallingSnow(DrawingCanvas aCanvas, Image aSnowPic, Wind w,
double x, double aSpeed) {
canvas = aCanvas;
ySpeed = aSpeed;
wind = w;
snow = new VisibleImage(aSnowPic, 0, 0, canvas);
snow.move(x, - snow.getHeight());
start();
}
public void run() {
// as long as the snow is still on the screen
// move it and pause
while (snow.getY() < canvas.getHeight()) {
pause(DELAY_TIME);
// we will query the Wind object to get the current wind speed
snow.move(wind.getSpeed(),ySpeed);
}
snow.removeFromCanvas();
}
}
import objectdraw.*;
import java.awt.*;
/*
*
* Example WindyFallingSnow: the main class that creates clouds, which in turn
* create falling snowflakes.
*
* This one adds a varying wind, controlled by another active object!
*
* Jim Teresco, The College of Saint Rose, Fall 2013, Fall 2014
* Based on example from CSCI 134, Williams College
*
* $Id: Snow.java 2452 2014-10-13 15:59:20Z terescoj $
*/
// Program which creates clouds which create snow when the user clicks
public class Snow extends WindowController {
// constants for the moon size and location
private static final double MOON_INSET = 50;
private static final int MOON_SIZE = 70;
// sizes and locations for the bricks
private static final double BRICK_LINE = 40; // from bottom
private static final double BRICK_HEIGHT = 12;
private static final double BRICK_WIDTH = 30;
private static final double BRICK_SPACING = 3;
// colors of the sky, mortar, and brick
private final Color NIGHTSKY = new Color(50, 50, 100);
private final Color MORTAR = new Color(200, 200, 200);
private final Color BRICKRED = new Color(150, 40, 40);
// image of the snow
private Image snowPic;
// our wind generator
private Wind wind;
public void begin() {
// where to draw next brick
double brickPosition;
// get leaf picture
snowPic = getImage("snow.gif");
// draw solid sky, mortar, and moon
new FilledRect(0, 0, canvas.getWidth(), canvas.getHeight() - BRICK_LINE, canvas).setColor(NIGHTSKY);
new FilledRect(0, canvas.getHeight() - BRICK_LINE, canvas.getWidth(),
canvas.getHeight(),
canvas).setColor(MORTAR);
new FilledOval(MOON_INSET,MOON_INSET,MOON_SIZE,MOON_SIZE,
canvas).setColor(Color.white);
// add the bricks
brickPosition = 0;
while ( brickPosition < canvas.getWidth() ) {
new FilledRect(brickPosition, canvas.getHeight() - BRICK_LINE,
BRICK_WIDTH, BRICK_HEIGHT,
canvas).setColor(BRICKRED);
brickPosition = brickPosition + BRICK_WIDTH + BRICK_SPACING;
}
// construct our Wind object that will be passed to each Cloud
// and in turn to each FallingSnow object, which will query it
// for current wind speeds.
wind = new Wind();
}
public void onMouseClick(Location point) {
// make a new snow-dropping cloud when the user clicks
// note the extra parameter for the Wind object
new Cloud(snowPic, wind, canvas);
}
}
import objectdraw.*;
import java.awt.*;
import java.util.Random;
/*
*
* Example FallingSnow: the cloud class which is responsible for
* creating a bunch of snowflakes, in this case remembering and
* passing along the Wind obect to each snowflake.
*
* Jim Teresco, Siena College, CSIS 120, Spring 2011
* The College of Saint Rose, Fall 2013, Fall 2014
* Based on example from CSCI 134, Williams College
*
* $Id: Cloud.java 2452 2014-10-13 15:59:20Z terescoj $
*/
public class Cloud extends ActiveObject {
// total number of snowflakes
private static final int MAX_SNOW = 150;
// time between flakes
private static final int FLAKE_INTERVAL = 900;
// the canvas
private DrawingCanvas canvas;
// picture of a snowflake
private Image snowPic;
// used to generate random speeds and positions for snowflakes
private Random snowGen;
// our Wind generator, just here to be passed along
private Wind wind;
public Cloud(Image aSnowPic, Wind wind, DrawingCanvas aCanvas) {
// save the parameters for the "run" method
canvas = aCanvas;
snowPic = aSnowPic;
this.wind = wind;
snowGen = new Random();
start();
}
public void run()
{
int snowCount= 0;
// continue creating snow until the maximum amount
// has been created
while (snowCount < MAX_SNOW ) {
snowCount = snowCount + 1;
new FallingSnow(canvas, snowPic, wind,
snowGen.nextInt((int)canvas.getWidth()), // x coordinate
snowGen.nextDouble()*2+2); // y speed
pause(FLAKE_INTERVAL);
}
}
}
import objectdraw.*;
import java.util.Random;
/**
* A class to generate a randomly-fluctuating wind.
*
* @author Jim Teresco, The College of Saint Rose
* Fall 2013
*
* $Id: Wind.java 2218 2013-10-18 14:06:39Z terescoj $
*/
public class Wind extends ActiveObject {
// constants to define the wind's behavior
// update the wind once per second
private static final int WIND_ADJ_DELAY = 1000;
// maximum change per iteration in wind speed
private static final double WIND_ADJ_MAX = 3.0;
// current wind velocity (x-direction)
private double currentWind;
// random number generator to generate changes in
// wind speed periodically
private Random r;
// construct and active our Wind object
public Wind() {
currentWind = 0.0;
r = new Random();
start();
}
// the life of the wind
public void run() {
// the wind never stops, it just changes direction
while (true) {
currentWind += ((r.nextDouble() * 2 * WIND_ADJ_MAX) - WIND_ADJ_MAX);
pause(WIND_ADJ_DELAY);
}
}
// public accessor method to allow our snowflakes to query the
// current wind velocity
public double getSpeed() {
return currentWind;
}
}