java graphics program案例 Create a graphics program to draw moving stars and other type of shapes.

java graphics program案例 科目Create a graphics program to draw moving stars and other type of shapes.

Ask user to input “how many objects do you want to create?“
draw (how many / 2) stars
draw (how many / 2) other shapes
apply collision detection to all the stars and shapes (right-left-top-bottom), and rebound after collision
You must use random class to set initial values of each shape (x, y, size, speedx, speedy, color, etc)
Sample code here:

import java.awt.Color;

import java.awt.Graphics;

import javax.swing.JFrame;

import java.util.*;

import java.awt.*;

import java.awt.event.*;

import javax.swing.*;







class Star {

int x;

int y;

int size;

int speedX;

int speedY;

Color color;

}




public class cs210Star extends JFrame {

public static ArrayListmyStar = new ArrayList<>();

static int width = 800;

static int height = 600;




static int howMany = 30;




public cs210Star() {     // Constructor (Ch08)

super("Your Title");

setBounds(100, 100, width, height);  // at your monitor

setResizable(false);

setVisible(true);

setDefaultCloseOperation(EXIT_ON_CLOSE);

}







public static void createStar() {

Random rand = new Random();

int R, G, B;

for (int i = 0; i < howMany; i++) {

Star s = new Star();

R = rand.nextInt(256);

G = rand.nextInt(256);

B = rand.nextInt(256);

s.color = new Color(R, G, B);

s.x = rand.nextInt(width);

s.y = rand.nextInt(height);

s.size = rand.nextInt(10) + 10;

s.speedX = rand.nextInt(5) + 1;

s.speedY = rand.nextInt(5) + 1; myStar.add(s);

}

}




public void paint(Graphics g) {

g.setColor(Color.BLACK);

g.fillRect(0, 0, width, height);

for (int i = 0; i < myStar.size(); i++) { // AllayList Size

g.setColor(myStar.get(i).color); myStar.get(i).x += myStar.get(i).speedX; myStar.get(i).y += myStar.get(i).speedY;




drawStar(g, myStar.get(i).x, myStar.get(i).y, myStar.get(i).size);

}

try {

Thread.sleep(10);

} catch (Exception exc) {

}

repaint();

}




public void drawStar(Graphics g, int sx, int sy, int size) {

int[] xCoords = new int[10];

int[] yCoords = new int[10];

int ang = 90 - 36;

double rad;

double PI = 3.14159;




for(int i = 0; i < 10; i++) { if (i % 2 == 0) rad = size * 0.38; else rad = size; xCoords[i] += (int)(rad * Math.cos(PI * ang / 180.0));

yCoords[i] -= (int)(rad * Math.sin(PI * ang / 180.0));

ang += 36;

xCoords[i] += getX();

yCoords[i] += getY();

}

g.fillPolygon(xCoords, yCoords, 10);




}




public static void main(String[] args) { createStar();

new cs210Star();

}

}