Now i try to draw a table by Canvas, but i have a problem, my table doesnt has scrollable.
How can i write some code to help my table can scrollable?
My Code here
import javax.microedition.lcdui.Canvas;
import javax.microedition.lcdui.Graphics;
/**
*
* #author Kency
*/
public class TableCanvas extends Canvas{
private int w,h;
private int pad;
private int cols = 3;
private int rows = 10;
public TableCanvas() {
w = getWidth();
h = getHeight();
}
protected void paint(Graphics g) {
g.setColor(148, 178, 255);
g.fillRect(0, 0, w, h);
for(int i =0 ; i <= cols ; i++){
g.setColor(0x00D0D0D0);
for(int j = 0 ; j <= rows ; j++){
g.drawLine(0, j * h/rows, cols * w, j* h/rows);
g.drawLine(i * w/cols, 0, i * w/cols, w * rows);
}
}
}
}
For code like in your excerpt, most straightforward way would probably be with Graphics#translate API.
One would also have to handle key pressed / pointer events to allow user to scroll. Eg when key press corresponds to game action right/left/up/down, you scroll respectively. When pointer is dragged, you find out the direction and, again, scroll respectively
Painting scrollbar(s) would also require "handmade" code.
Another option would be using 3rd party library like LWUIT or J2ME Polish
Related
I need to create board game that can be dynamically change.
Its size can be 5x5, 6x6, 7x7 or 8x8.
I am jusing JavaFX with NetBeans and Scene builder for the GUI.
When the user choose board size greater than 5x5 this is what happens:
This is the template on the scene builder before adding cells dynamically:
To every cell in the GridPane I am adding StackPane + label of the cell number:
#FXML
GridPane boardGame;
public void CreateBoard()
{
int boardSize = m_Engine.GetBoard().GetBoardSize();
int num = boardSize * boardSize;
int maxColumns = m_Engine.GetNumOfCols();
int maxRows = m_Engine.GetNumOfRows();
for(int row = 0; row < maxRows ; row++)
{
for(int col = maxColumns - 1; col >= 0 ; col--)
{
StackPane stackPane = new StackPane();
stackPane.setPrefSize(150.0, 200.0);
stackPane.getChildren().add(new Label(String.valueOf(num)));
boardGame.add(stackPane, col, row);
num--;
}
}
boardGame.setGridLinesVisible(true);
boardGame.autosize();
}
The problem is the stack panes's size on the GridPane are getting smaller.
I tried to set them equal minimum and maximum size but it didn't help they are still getting smaller.
I searched on the web but didn't realy find same problem as mine.
The only similar problem to mine was found here:
Dynamically add elements to a fixed-size GridPane in JavaFX
But his suggestion is to use TilePane and I need to use GridPane because this is a board game and it more easier to use GridPane when I need to do tasks such as getting to cell on row = 1 and column = 2 for example.
EDIT:
I removed the GridPane from the FXML and created it manually on the Controller but now it print a blank board:
#FXML
GridPane boardGame;
public void CreateBoard()
{
int boardSize = m_Engine.GetBoard().GetBoardSize();
int num = boardSize * boardSize;
int maxColumns = m_Engine.GetNumOfCols();
int maxRows = m_Engine.GetNumOfRows();
boardGame = new GridPane();
boardGame.setAlignment(Pos.CENTER);
Collection<StackPane> stackPanes = new ArrayList<StackPane>();
for(int row = 0; row < maxRows ; row++)
{
for(int col = maxColumns - 1; col >= 0 ; col--)
{
StackPane stackPane = new StackPane();
stackPane.setPrefSize(150.0, 200.0);
stackPane.getChildren().add(new Label(String.valueOf(num)));
boardGame.add(stackPane, col, row);
stackPanes.add(stackPane);
num--;
}
}
this.buildGridPane(boardSize);
boardGame.setGridLinesVisible(true);
boardGame.autosize();
boardGamePane.getChildren().addAll(stackPanes);
}
public void buildGridPane(int i_NumOfRowsAndColumns)
{
RowConstraints rowConstraint;
ColumnConstraints columnConstraint;
for(int index = 0 ; index < i_NumOfRowsAndColumns; index++)
{
rowConstraint = new RowConstraints(3, Control.USE_COMPUTED_SIZE, Double.POSITIVE_INFINITY, Priority.ALWAYS, VPos.CENTER, true);
boardGame.getRowConstraints().add(rowConstraint);
columnConstraint = new ColumnConstraints(3, Control.USE_COMPUTED_SIZE, Double.POSITIVE_INFINITY, Priority.ALWAYS, HPos.CENTER, true);
boardGame.getColumnConstraints().add(columnConstraint);
}
}
Changed your code slightly with explanations in comments. HTH.
GridPane boardGame;
public void CreateBoard()
{
int boardSize = m_Engine.GetBoard().GetBoardSize();
int num = boardSize * boardSize;
int maxColumns = m_Engine.GetNumOfCols();
int maxRows = m_Engine.GetNumOfRows();
boardGame = new GridPane();
boardGame.setAlignment(Pos.CENTER);
Collection<StackPane> stackPanes = new ArrayList<StackPane>();
for(int row = 0; row < maxRows ; row++)
{
for(int col = maxColumns - 1; col >= 0 ; col--)
{
StackPane stackPane = new StackPane();
// To occupy fixed space set the max and min size of
// stackpanes.
// stackPane.setPrefSize(150.0, 200.0);
stackPane.setMaxSize(100.0, 100.0);
stackPane.setMinSize(100.0, 100.0);
stackPane.getChildren().add(new Label(String.valueOf(num)));
boardGame.add(stackPane, col, row);
stackPanes.add(stackPane);
num--;
}
}
// No need to add column and row constraints if you want just a uniform
// rigid grid view. So commented the line below.
// this.buildGridPane(boardSize);
boardGame.setGridLinesVisible(true);
boardGame.autosize();
// Here you are adding all stackpanes, those are added to the gridpane 'boardGame'
// before, to the another gridpane with name 'boardGamePane'. So all stackpanes are moved
// to this second gridpane. This is the reason of blank board you are seeing.
// So commenting this out also.
// boardGamePane.getChildren().addAll(stackPanes);
}
I want to make something like Terraria item sidebar thing. (the Left-top rectangles one). And here is my code.
Variables are
public Rectangle InventorySlots;
public Item[] Quickbar = new Item[9];
public Item mouseItem = null;
public Item[] Backpack = new Item[49];
public int selectedBar = 0;
Here is the initialization
inventory[0] = Content.Load<Texture2D>("Contents/Overlays/InventoryBG");
inventory[1] = Content.Load<Texture2D>("Contents/Overlays/InventoryBG2");
update method
int a = viewport.Width / 22;
for (int b = 0; b <= Quickbar.Length; ++b)
{
InventorySlots = new Rectangle(((a/10)*b)+(b),0,a,a);
}
draw method
spriteBatch.Begin();
for (int num = 0; num <= Quickbar.Length; ++num )
spriteBatch.Draw(inventory[0], InventorySlots, Color.White);
spriteBatch.Draw(inventory[1], InventorySlots, Color.White);
spriteBatch.End();
Yes it is not done, but when i try to run it, the texture didn't show up.
I am unable to find out what is wrong in my code.
is it in with SpriteBatch? In the draw method? or In the Update?
Resolved
The problem isnt at the code Itself. the Problem is in this:
int a = viewport.Width / 22;
The thing is, i trought that viewport in here (I've used a Starter Kit) is the Game Window!
You are assigning InventorySlots overwriting its content...
also it seems that you want to draw two sprites... but you are drawing only one inside the loop... and your looping over Quickbar when seems that its not related with your drawing calls.
And it seems that your slot layout calculations have few sense...
You should use an array or a list:
public List<Rectangle> InventorySlots = new List<Rectangle>();
// You put this code in update... but it's not going to change..
// maybe initialize is best suited
// Initialize
int a = viewport.Width / 22;
InventorySlots.Clear();
for (int b = 0; b < Quickbar.Length; ++b)
{ // Generate slots in a line, with a pixel gap among them
InventorySlots.Add( new Rectangle( 1 + (a+2) * b ,0,a,a) );
}
//Draw
spriteBatch.Begin();
for (int num = 0; num < InventorySlots.Count; ++num )
{
spriteBatch.Draw(inventory[0], InventorySlots[num], Color.White);
spriteBatch.Draw(inventory[1], InventorySlots[num], Color.White);
}
spriteBatch.End();
I'm trying to create a scrollView, but I don't know how to determine the maximum range of the scroll (or even better, the maximum scroll position).
This is what I have tried to do without any positive results:
void Update()
{
//get the amount of space that my text is taking
textSize = gs.CalcHeight(new GUIContent(text), (screenWidth/2));
if(Input.touchCount > 0 && Input.GetTouch(0).phase == TouchPhase.Moved && Input.GetTouch(0).tapCount==1)
{
var touch = Input.touches[0];
//check if touch is within the scrollView area
if(touch.position.x >= (screenWidth/2) && touch.position.x <= (screenWidth) && touch.position.y >= 0 && touch.position.y <= (screenHeight))
{
if(touch.phase == TouchPhase.Moved)
{
scrollPosition[1] += touch.deltaPosition.y;
if(scrollPosition[1] < 0)
{
scrollPosition[1] = 0;
}
//I subtracted this cause i read that the scrollbars take 16px
if(scrollPosition[1] > (textSize-scrollViewRect.yMax-16)) //scrollViewRect is a Rect with the size of my scrollView
{
scrollPosition[1] = textSize-scrollViewRect.yMax-16;
}
}
}
}
}
void OnGUI()
{
screenWidth = camera.pixelWidth;
screenHeight = camera.pixelHeight;
GUILayout.BeginArea(new Rect(screenWidth/2, 0, screenWidth/2, screenHeight));
GUILayout.BeginScrollView(scrollPosition/*, GUILayout.Width (screenWidth/2), GUILayout.Height (screenHeight/2)*/, "box");
GUILayout.Label (new GUIContent(text), gs);
// End the scrollview
GUILayout.EndScrollView ();
scrollViewRect = GUILayoutUtility.GetLastRect();
GUILayout.EndArea();
}
This was done assuming that the scrollView is on the right half of the screen.
Can you guys help me out on this?
Thanks in advance.
As shown in the API documentation for GUI.BeginScrollView, you can assign a Vector2 to the declaration of BeginScrollView to track and update where the box has been scrolled to.
I'll give an example:
using UnityEngine;
using System.Collections;
public class ScrollSize : MonoBehaviour {
private int screenBoxX = Screen.width;
private int screenBoxY = Screen.height;
private int scrollBoxX = Screen.width * 2;
private int scrollBoxY = Screen.height * 3;
public Vector2 scrollPosition = Vector2.zero;
void Awake()
{
Debug.Log ("box size is " + scrollBoxX + " " + scrollBoxY);
}
void OnGUI()
{
scrollPosition = GUI.BeginScrollView(new Rect(0, 0, screenBoxX, screenBoxY),
scrollPosition, new Rect(0, 0, scrollBoxX, scrollBoxY));
GUI.EndScrollView();
// showing 4 decimal places
Debug.Log ("Box scrolled # " + scrollPosition.ToString("F4"));
}
}
For the explanation of this example, let's assume that the screen resolution is 800 by 600.
Therefore the viewable scrollbox on the screen will be 800 wide and 600 high, with the internal area of the scrollbox being 1600 by 1800.
We create the scrollbox by assigning Gui.BeginScrollView() as the value of Vector2, scrollPosition. As the scrollbox is scrolled horizontally and vertically, the Vector2 will update with the scrolled value.
If the scrollbox is scrolled to the top-leftmost position, the value of scrollPosition will be 0,0.
If the scrollbox is scrolled to the bottom-rightmost position, the value of scrollPosition will be 816, 616, the size of the box on screen plus the thickness of the scroll bars.
I know this is 3 years later but maybe it will help others too...
I found that setting the scrollPosition to a very high number will force the scrollbar to the bottom:
scrollPosition.y = 999.9f;
Then you can read the position like this:
scrollPosition = GUILayout.BeginScrollView(scrollPosition,
GUILayout.Width(370),
GUILayout.Height(135));
And it will be set to whatever the maximum is.
Hope this helps!
This is first time I at a question in here.
Im new in J2ME, and now im developing a small application, but i get problem when i wanna show data into table. But in J2me not support table there for that i know another way can represent for table such as create table by Canvas or CustomItem.
In Canvas i can draw 2 lines something like:
-----------------------
|
|
|
|
but i dont know how can get coordinate of 2 lines remain such as like:
|
|
|
|
|
--------------------------
two draw a rectangular in whole screen,
i know drawline method has 4 factors x1,y1,x2,y2.
but i can not calculate x point and y point to draw two lines above
I need you help me explain or give me example
My Code:
package test;
import javax.microedition.lcdui.Canvas;
import javax.microedition.lcdui.Graphics;
/**
*
* #author J2MENewBie
*/
public class TableCanvasExample extends Canvas {
private int cols=3;
private int rows =50;
protected void paint(Graphics g) {
g.setColor(0x94b2ff);
g.fillRect(0, 0, this.getWidth(), this.getHeight());
//draw two lines
g.setColor(0xf8011e);
g.drawLine(0, 0, 0, this.getWidth());
g.drawLine(0, 0, this.getHeight(), 0);
}
}
package test;
import javax.microedition.lcdui.Display;
import javax.microedition.midlet.*;
/**
* #author J2ME NewBie
*/
public class TableCanvasMidlet extends MIDlet {
private TableCanvasExample tbcve;
public TableCanvasMidlet(){
tbcve = new TableCanvasExample();
}
public void startApp() {
Display.getDisplay(this).setCurrent(tbcve);
}
public void pauseApp() {
}
public void destroyApp(boolean unconditional) {
}
}
P/s: the vertical line doesn't full size i dont know why ???
Thank you!
too much same-looking zeroes in your code - try using descriptive names instead:
int w = getWidth(), h = getHeight(); // I think this way it's easier to read
int xLeft = 0, yTop = 0; // descriptive names for zeroes
// below, replace w - 1 -> w and h - 1 -> h if lines drawn are off-by-one
int xRight = w - 1, yBottom = h - 1; // names for top - right coordinates
g.drawLine(xLeft, yTop, xLeft, yBottom); // your left vertical
g.drawLine(xLeft, yTop, xRight, yTop); // your top horizontal
g.drawLine(xRight, yTop, xRight, yBottom); // add right vertical
g.drawLine(xLeft, yBottom, xRight, yBottom); // add bottom horizontal
if rectangle drawn doesn't look like you expect find where there is wrong semantic in code above
I am making a simplified version of the ball physics app found at this SO question. I gained a lot from reading through the code and links provided at that question, but in my program I do not use vectors, I just update the coordinates of my balls (each of which has a random angle and speed) with trigonometry functions when they hit the walls.
There is info all over the place for how to handle ball to ball collisions without trigonometry, but I have found none that explain how it can be done with trigonometry.
--EDIT 9/13/2010--
Success... kind of... I got done what I wanted to do, but I was unable to do it how I wanted. If there is a way to calculate ball to ball collisions without the use of vectors it has eluded me. Even so, vectors do seem to be an easier way to handle collisions of all types... I just wish I would have known that when I started my program... would have saved me two or three days of work :) All the code for my (complete?) program is below. I added some neat features like shadows and a decreasing ball radius which really lets you see the difference in the mass of two balls when a big ball hits a small ball. In total there are five class files, AddLogic.java, Ball.java, BallBuilder.java, MouseEventHandler.java, and Vector2D.java.
AddLogic.java
import java.awt.*;
import java.awt.Graphics2D;
import java.awt.image.BufferStrategy;
import java.util.ArrayList;
public class AddLogic implements Runnable {//Make AddLogic a runnable task.
private BallBuilder ballBuilder;
private BufferStrategy strategy;
private static ArrayList objectsToDraw = new ArrayList();
private int floorHeight = 33;
public AddLogic(BallBuilder ballBuilder, BufferStrategy strategy) {
this.ballBuilder = ballBuilder;
this.strategy = strategy;
}
private void logic(BallBuilder ballBuilder, BufferStrategy strategy) {
this.ballBuilder = ballBuilder;
this.strategy = strategy;
while (true) {//Main loop. Draws all objects on screen and calls update methods.
Graphics2D g = (Graphics2D) strategy.getDrawGraphics();//Creates the Graphics2D object g and uses it with the double buffer.
g.setColor(Color.gray);
g.fillRect(0, 0, ballBuilder.getWidth(), ballBuilder.getHeight());//Draw the wall.
g.setColor(Color.lightGray);
g.fillRect(0, ballBuilder.getHeight() - floorHeight, ballBuilder.getWidth(), floorHeight);//Draw the floor.
g.setColor(Color.black);
g.drawLine(0, ballBuilder.getHeight() - floorHeight, ballBuilder.getWidth(), ballBuilder.getHeight() - floorHeight);//Draw the line between the wall and floor.
if (objectsToDrawIsEmpty() == true) {//If no balls have been made display message telling users how to make new ball.
g.setColor(Color.red);
g.drawString("Click Mouse For New Ball", (ballBuilder.getWidth() / 2) - 70, ballBuilder.getHeight() / 2);
}
for (int i = 0; i < objectsToDraw.size(); i++) {//Draw shadows for all balls.
Ball ball = (Ball) objectsToDraw.get(i);
g.setColor(Color.darkGray);
g.fillOval(
(int) ball.ballPosition.getX() - (int) ((ball.ballPosition.getY() / (350 / ball.getBallRadius())) / 2),
ballBuilder.getHeight() - (floorHeight / 2) - (int) ((ball.ballPosition.getY() / (1250 / ball.getBallRadius())) / 2),
(int) ball.ballPosition.getY() / (350 / ball.getBallRadius()),
(int) ball.ballPosition.getY() / (1250 / ball.getBallRadius()));
}
for (int i = 0; i < objectsToDraw.size(); i++) {//Draw all balls by looping through them and checking for any vector or collision updates that need to be made.
Ball ball = (Ball) objectsToDraw.get(i);
g.setColor(ball.getBallColor());
g.fillOval(
(int) ball.ballPosition.getX() - ball.getBallRadius(),
(int) ball.ballPosition.getY() - ball.getBallRadius(),
ball.getBallRadius() * 2,
ball.getBallRadius() * 2);
vectorUpdate(ball);//Update ball vector coordinates.
collisionCheck(ball);//Check ball to ball and ball to wall collisions.
}
if (MouseEventHandler.mouseEventCheck() == true) {// Creates a new ball when mouse is clicked.
Ball ball = new Ball(ballBuilder);
objectsToDraw.add(ball); //Adds the new ball to the array list.
MouseEventHandler.mouseEventUpdate(); //Resets the mouse click event to false.
}
g.dispose();//To aid Java in garbage collection.
strategy.show();//Show all graphics drawn on the buffer.
try {//Try to make thread sleep for 5ms. Results in a frame rate of 200FPS.
Thread.sleep(5);
}
catch (Exception e) {//Catch any exceptions if try fails.
}
}
}
private void vectorUpdate(Ball ball) {//Update the ball vector based upon the ball's current position and its velocity.
ball.ballPosition.setX(ball.ballPosition.getX() + ball.ballVelocity.getX());
ball.ballPosition.setY(ball.ballPosition.getY() + ball.ballVelocity.getY());
}
private void collisionCheck(Ball ball) {//Check for ball to wall collisions. Call check for ball to ball collisions at end of method.
if (ball.ballPosition.getX() - ball.getBallRadius() < 0) {//Check for ball to left wall collision.
ball.ballPosition.setX(ball.getBallRadius());
ball.ballVelocity.setX(-(ball.ballVelocity.getX()));
ball.decreaseBallRadius(ball);//Decrease ball radius by one pixel. Called on left, top, and right walls, but not bottom because it looks weird watching shadow get smaller during bottom bounce.
}
else if (ball.ballPosition.getX() + ball.getBallRadius() > ballBuilder.getWidth()) {//Check for ball to right wall collision.
ball.ballPosition.setX(ballBuilder.getWidth() - ball.getBallRadius());
ball.ballVelocity.setX(-(ball.ballVelocity.getX()));
ball.decreaseBallRadius(ball);//Decrease ball radius by one pixel. Called on left, top, and right walls, but not bottom because it looks weird watching shadow get smaller during bottom bounce.
}
if (ball.ballPosition.getY() - ball.getBallRadius() < 0) {//Check for ball to top wall collision.
ball.ballPosition.setY(ball.getBallRadius());
ball.ballVelocity.setY(-(ball.ballVelocity.getY()));
ball.decreaseBallRadius(ball);//Decrease ball radius by one pixel. Called on left, top, and right walls, but not bottom because it looks weird watching shadow get smaller during bottom bounce.
}
else if (ball.ballPosition.getY() + ball.getBallRadius() + (floorHeight / 2) > ballBuilder.getHeight()) {//Check for ball to bottom wall collision. Floor height is accounted for to give the appearance that ball is bouncing in the center of the floor strip.
ball.ballPosition.setY(ballBuilder.getHeight() - ball.getBallRadius() - (floorHeight / 2));
ball.ballVelocity.setY(-(ball.ballVelocity.getY()));
}
for (int i = 0; i < objectsToDraw.size(); i++) {//Check to see if a ball is touching any other balls by looping through all balls and checking their positions.
Ball otherBall = (Ball) objectsToDraw.get(i);
if (ball != otherBall && Math.sqrt(Math.pow(ball.ballPosition.getX() - otherBall.ballPosition.getX(), 2.0) + Math.pow(ball.ballPosition.getY() - otherBall.ballPosition.getY(), 2.0)) < ball.getBallRadius() + otherBall.getBallRadius()) {
resolveBallToBallCollision(ball, otherBall);//If the ball is hitting another ball calculate the new vectors based on the variables of the balls involved.
}
}
}
private void resolveBallToBallCollision(Ball ball, Ball otherBall) {//Calculate the new vectors after ball to ball collisions.
Vector2D delta = (ball.ballPosition.subtract(otherBall.ballPosition));//Difference between the position of the two balls involved in the collision.
float deltaLength = delta.getLength();//The (x, y) of the delta squared.
Vector2D minimumTranslationDistance = delta.multiply(((ball.getBallRadius() + otherBall.getBallRadius()) - deltaLength) / deltaLength);//The minimum distance the balls should move apart once they.
float ballInverseMass = 1 / ball.getBallMass();//half the ball mass.
float otherBallInverseMass = 1 / otherBall.getBallMass();//half the other ball mass.
ball.ballPosition = ball.ballPosition.add(minimumTranslationDistance.multiply(ballInverseMass / (ballInverseMass + otherBallInverseMass)));//Calculate the new position of the ball.
otherBall.ballPosition = otherBall.ballPosition.subtract(minimumTranslationDistance.multiply(otherBallInverseMass / (ballInverseMass + otherBallInverseMass)));//Calculate the new position of the other ball.
Vector2D impactVelocity = (ball.ballVelocity.subtract(otherBall.ballVelocity));//Find the veloicity of the impact based upon the velocities of the two balls involved.
float normalizedImpactVelocity = impactVelocity.dot(minimumTranslationDistance.normalize());//
if (normalizedImpactVelocity > 0.0f) {//Returns control to calling object if ball and other ball are intersecting, but moving away from each other.
return;
}
float restitution = 2.0f;//The constraint representing friction. A value of 2.0 is 0 friction, a value smaller than 2.0 is more friction, and a value over 2.0 is negative friction.
float i = (-(restitution) * normalizedImpactVelocity) / (ballInverseMass + otherBallInverseMass);
Vector2D impulse = minimumTranslationDistance.multiply(i);
ball.ballVelocity = ball.ballVelocity.add(impulse.multiply(ballInverseMass));//Change the velocity of the ball based upon its mass.
otherBall.ballVelocity = otherBall.ballVelocity.subtract(impulse.multiply(otherBallInverseMass));//Change the velocity of the other ball based upon its mass.
}
public static boolean objectsToDrawIsEmpty() {//Checks to see if there are any balls to draw.
boolean empty = false;
if (objectsToDraw.isEmpty()) {
empty = true;
}
return empty;
}
public void run() {//Runs the AddLogic instance logic in a new thread.
logic(ballBuilder, strategy);
}
}
Ball.java
import java.awt.*;
public class Ball {
private int ballRadius;
private float ballMass;
public Vector2D ballPosition = new Vector2D();
public Vector2D ballVelocity = new Vector2D();
private Color ballColor;
public Ball(BallBuilder ballBuilder) {//Construct a new ball.
this.ballRadius = 75;//When ball is created make its radius 75 pixels.
this.ballMass = ((float)(4 / 3 * Math.PI * Math.pow(ballRadius, 3.0)));//When ball is created make its mass that the volume of a sphere the same size.
this.ballPosition.set(ballRadius, ballBuilder.getHeight() - ballRadius);//When ball is created make its starting coordinates the bottom left hand corner of the screen.
this.ballVelocity.set(randomVelocity(), randomVelocity());//When ball is created make its (x, y) velocity a random value between 0 and 2.
if (AddLogic.objectsToDrawIsEmpty() == true) {//If the ball being created is the first ball, make it blue, otherwise pick a random color.
this.ballColor = Color.blue;
} else {
this.ballColor = randomColor();
}
}
public void decreaseBallRadius(Ball ball){//Decrease the ball radius.
if(ball.getBallRadius() <= 15){//If the ball radius is less than or equal to 15 return control to calling object, else continue.
return;
}
ball.setBallRadius(ball.getBallRadius() - 1);//Decrease the ball radius by 1 pixel.
ball.setBallMass((float)(4 / 3 * Math.PI * Math.pow(ballRadius, 3.0)));//Recalcualte the mass based on the new radius.
}
public int getBallRadius() {
return ballRadius;
}
public float getBallMass(){
return ballMass;
}
public Color getBallColor() {
return ballColor;
}
private void setBallRadius(int newBallRadius) {
this.ballRadius = newBallRadius;
}
private void setBallMass(float newBallMass){
this.ballMass = newBallMass;
}
private float randomVelocity() {//Generate a random number between 0 and 2 for the (x, y) velocity of a ball.
float speed = (float)(Math.random() * 2);
return speed;
}
private Color randomColor() {//Generate a random color for a new ball based on the generation of a random red, green, and blue value.
int red = (int) (Math.random() * 255);
int green = (int) (Math.random() * 255);
int blue = (int) (Math.random() * 255);
ballColor = new Color(red, green, blue);
return ballColor;
}
}
BallBuilder.java
import java.awt.*;
import java.awt.image.*;
import java.util.concurrent.*;
import javax.swing.*;
public class BallBuilder extends Canvas{
private int frameHeight = 600;
private int frameWidth = 800;
private static BufferStrategy strategy;//Create a buffer strategy named strategy.
public BallBuilder(){
setIgnoreRepaint(true);//Tell OS that we will handle any repainting manually.
setBounds(0,0,frameWidth,frameHeight);
JFrame frame = new JFrame("Bouncing Balls");
JPanel panel = new JPanel();
panel.setPreferredSize(new Dimension(frameWidth, frameHeight));
panel.add(this);
frame.setContentPane(panel);
frame.pack();
frame.setResizable(false);
frame.setVisible(true);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
addMouseListener(new MouseEventHandler());
createBufferStrategy(2);//Create a double buffer for smooth graphics.
strategy = getBufferStrategy();//Apply the double buffer to the buffer strategy named strategy.
}
public static void main(String[] args) {
BallBuilder ballBuilder = new BallBuilder(); // Creates a new ball builder.
ExecutorService executor = Executors.newSingleThreadExecutor();//Creates a thread executor that uses a single thread.
executor.execute(new AddLogic(ballBuilder, strategy));//Executes the runnable task AddLogic on the previously created thread.
}
}
MouseEventHandler.java
import java.awt.event.*;
public class MouseEventHandler extends MouseAdapter{
private static boolean mouseClicked = false;
public void mousePressed(MouseEvent e){//If either of the mouse buttons is pressed the mouse clicked variable is set to true.
mouseClicked = true;
}
public static void mouseEventUpdate(){//When called, sets the mouse clicked variable back to false.
mouseClicked = false;
}
public static boolean mouseEventCheck(){//Returns the state of the mouse clicked variable.
if(mouseClicked){
return true;
}
else{
return false;
}
}
}
Vector2D
public class Vector2D {//A class that takes care of ball position and speed vectors.
private float x;
private float y;
public Vector2D() {
this.setX(0);
this.setY(0);
}
public Vector2D(float x, float y) {
this.setX(x);
this.setY(y);
}
public void set(float x, float y) {
this.setX(x);
this.setY(y);
}
public void setX(float x) {
this.x = x;
}
public void setY(float y) {
this.y = y;
}
public float getX() {
return x;
}
public float getY() {
return y;
}
public float dot(Vector2D v2) {//Speciality method used during calculations of ball to ball collisions.
float result = 0.0f;
result = this.getX() * v2.getX() + this.getY() * v2.getY();
return result;
}
public float getLength() {
return (float) Math.sqrt(getX() * getX() + getY() * getY());
}
public Vector2D add(Vector2D v2) {
Vector2D result = new Vector2D();
result.setX(getX() + v2.getX());
result.setY(getY() + v2.getY());
return result;
}
public Vector2D subtract(Vector2D v2) {
Vector2D result = new Vector2D();
result.setX(this.getX() - v2.getX());
result.setY(this.getY() - v2.getY());
return result;
}
public Vector2D multiply(float scaleFactor) {
Vector2D result = new Vector2D();
result.setX(this.getX() * scaleFactor);
result.setY(this.getY() * scaleFactor);
return result;
}
public Vector2D normalize() {//Speciality method used during calculations of ball to ball collisions.
float length = getLength();
if (length != 0.0f) {
this.setX(this.getX() / length);
this.setY(this.getY() / length);
} else {
this.setX(0.0f);
this.setY(0.0f);
}
return this;
}
}
The speed angle changes when the ball bounces, you should change it after each bounce.
Also, as you'll see later, the speed VALUE (called "modulus") also changes when two balls collide.
EDIT:::
It seems to me that you are accelerating the balls
The
int x = (int) (ball.getBallTempX() +
(ball.getBallPathLength() * Math.cos(ball.getBallAngle())));
Seems to correspond to
int x = (int) (ball.getBallTempX() +
(ball.getBallSpeed() * Math.cos(ball.getBallAngle())));
And the same for "y"
Am I right?
Edit 2::
In fact, you don't need the TempX,TempY,PreviousCenterX and PreviousCenterY either.
Try these methods
private int xCoordinateUpdate(Ball ball) {
int x = (int) (ball.getBallCenterX()+ (ball.Speed()
* Math.cos(ball.getBallAngle())));
return x;
(the same for Y)
Edit 3 ::
One more ... :)
What you need is to code is this formula (any other will fail when you attempt to collide balls):
Pseudocode >
BallCenterX = BallCenterX + BallSpeed * Math.cos(angle)
BallCenterY = BallCenterY + BallSpeed * Math.sin(angle)
Forget any "temp" and "old" values. They will impair your ball colliding feature.
I'll start this answer and keep editing it step by step until we are done. I'll try to guide you to a "semi-vectorized" version of the program, trying to minimize the effort.
Please keep updating the code as you progress, and commenting on my suggestions.
First, a few things:
In
private double randomBallAngle(){
ballAngle = Math.toRadians((Math.random()*90));
return ballAngle;
}
You are working in radians, but in yCoordinateUpdate and yCoordinateUpdate it seems that you are using the same angle in grads (because you are comparing with 90).
Using radians is easier for all the math involved.
Also, the vars GoingUp, etc are not needed since the speed angle will take care of that.
You may set the initial random angle in the interval (0 ... 2 Pi).
You should change (in fact reflect) the speed angle after each border collission (and afterwards, when we are done, after each inter-ball caollission too).
For this reflection, the laws are:
Upper or lower wall: New Angle = - OldAngle
For Right or left wall: New Angle = Pi - OldAngle
We'll keep reflections on the vertex for later ...