I have this code for my DoLogic method. And I'm trying to do a intersection between the shots and the obstacles but I really can't think of nothing.. cause both are different objects.. i tried to do some but it didn't really detect something at all.
for(int i=0; i<shots.length; i++)
{
if(shots[i] != null)
{
shots[i].moveShot(SHOTSPEED);
if(shots[i].getXPos() > 1280)
{
shots[i] = null;
}
}
}
for(int i=0; i<obstacles.length; i++)
{
if(obstacles[i] == null)
{
obstacles[i] = generateObstacle();
break;
}
if(obstacles[i] != null)
{
obstacles[i].moveObstacle();
if(obstacles[i].getXPos() < 10)
{
obstacles[i] = null;
}
else if(obstacles[i].intersects(Player1.character))
{
obstacles[i] = null;
GameSounds.hit("/resources/8bit_bomb_explosion.wav");
lives--;
}
}
}
Can you guys give me an example or at least an advice how to do an intersection between an obstacle and a shot?
Do these classes implement Shape? If not, they should. See the answer to Collision detection with complex shapes for an SSCCE.
..and i should implement the Rectangle in Obstacle and Oval in shot?
That seems logical to me, from your description of both objects.
..i just type implements Shape?
I would tend to use a Rectangle2D or Rectangle2D.Double for the obstacle & an Ellipse2D or Ellipse2D.Double for the shot. Rather than extend them, just hold them as an instance variable.
Give it a go & let us know how you go. If you get stuck, post an SSCCE of your best attempt.
You might need to hot-link to some small images.
.. ..
Related
I'm finishing my homework in OOP Java. The assignment is to load images on a JFrame, be able to move them around (top layer should be prioritized, it is currently not) and click them to "flip them" (change the source of the image essentially). I'm currently having trouble finding a solution on how to properly "layer" images that are visible on the screen and to prioritize the images on the top first (currently the bottom ones are being prioritized).
I also have issues finding a good way to change the source of the images, as our teacher has prohibited extending the Picture class with Swing.
My first attempt at solving this was saving the information of every individual "Picture" object in an ArrayList. This works to save the position of the images but does not solve my issue with the layering. I also wanted to use JLayeredPane but as I found out, it was harder than I thought as I have yet to find a viable solution this way (I might be missing some obvious facts about how it works).
I'm thinking what probably needs to happen is that I save the "position" of each image in some type of Array, then using this array to print out the images via paintComponent # ImagePanel. This is currently what I am doing but it does not act as I wish it to. I think my way of loading in the images in the "Picture" class might have something to do with it. I don't have a lot of experience in Java so all of this is new to me.
I don't want to print out all of my codes as I have 4 classes, so I'm going to print out what I feel are the essential methods in each class. If there's something missing that you guys need in order to guide me in the right direction I'll provide that aswell.
draw # Picture
public void draw(Graphics g, int i) {
try {
BufferedImage img = ImageIO.read(new File("images/icon_"+ i +".gif"));
g.drawImage(img, x, y, null);
} catch(IOException ie) {
System.out.println("Could not find images");
}
}
mousePressed & mouseDragged # MouseHandler
public void mousePressed (MouseEvent e) {
Point point = e.getPoint();
chosen = imagepanel.locateImage(point);
}
public void mouseDragged (MouseEvent e) {
int x = e.getX();
int y = e.getY();
if (chosen != null) {
imagepanel.moveImage(chosen, x, y);
}
}
loadImages & paintComponent # ImagePanel
private final static int IMAGES = 7;
private ArrayList <Picture> imageCollection = new ArrayList<>();
private Picture im;
Random rand = new Random();
public void loadImages() {
for(int i=0; i<IMAGES; i++) {
int x = rand.nextInt(400) + 40;
int y = rand.nextInt(400) + 60;
im = new Picture(x,y);
imageCollection.add(im);
}
}
#Override
public void paintComponent(Graphics g) {
super.paintComponent(g);
int i = 0;
for (Picture im : imageCollection) {
i++;
im.draw(g, i);
}
}
I expect the images to stack on top of eachother whenever "flipped" (clicked) or moved (dragged). They do not currently do this as they just maintain their "depth" position. I've tried implementing an Image[] without success.
I also have a flip method where I tried using setIcon (I was using ImageIcon instead of Image previously) but this did not really work for some reason.
I also would love for any feedback on the code so far and any improvements that could be made as I always want to improve.
EDIT: I manage to solve my problems, however I'm sure there's a better way to do this.
public void placeFirst(Picture im) {
int pos = imageCollection.indexOf(im);
imageCollection.remove(pos);
imageCollection.add(0, im);
}
public void flipImage(Picture im) {
im.flip();
placeFirst(im);
repaint();
}
public void moveImage(Picture im, Point point) {
im.move(point.x-(im.getWidth(im)/2), point.y-(im.getHeight(im)/2));
placeFirst(im);
repaint();
}
public Picture locateImage(Point point) {
for (int i=0; i<imageCollection.size(); i++) {
Picture im = imageCollection.get(i);
if (im.fits(point)) {
return im;
}
}
return null;
}
#Override
public void paintComponent(Graphics g) {
super.paintComponent(g);
// There probably exists a better and visually nicer way of doing this
for (int i=imageCollection.size()-1; i>=0; i--) {
Picture im = imageCollection.get(i);
im.draw(g);
}
}
chosen = imagepanel.locateImage(point);
Well, we don't know how the locateImage(...) method works, but I would guess you just iterate through the array until you find a match.
So you will always find the same match.
So if you want an image to stack on top you have two issues:
you need to modify the search order so that when you click on an image you move it to position 0 in the ArrayList so it is always found first
but know when you paint images you need to paint images from the end of the ArrayList to the beginning, so the first image in the ArrayList gets painted last.
I am trying to draw points on canvas with different colors. Basically, Current point in Blue, Point drawn before current point in Green and Point draw after current point in red. Please see the code
private void setElemColor(GC g, int pos) {
int currentPoint = messtisch.getPointPos(); //current point, number
if (pos > currentPoint) {
g.setForeground(cRed);
} else if (pos == currentPoint) {
g.setForeground(cBlue);
} else if (pos < currentPoint) {
g.setForeground(cGreen);
}
}
to increase the comprehension. This works perfect. But I am trying to use Point in place of Int to do same and not getting logic right. As in
private void setPointColor(GC g, Point cpoint) {
if (cpoint.equals(currentPoint)) { // the current point itself
g.setForeground(cBlue);
} else if (!cpoint.equals(currentPoint)) {
if (cpoint.x > currentPoint.x || cpoint.y > currentPoint.y) {
g.setForeground(cRed);
} else {
g.setForeground(cGreen);
}
}
}
Please help me regarding.
I did it by using a new ArrayList and saving points to that are already been currentPoint. And then drawing them in Green color as old points. Here is my code sample.
private ArrayList<Point> oldpoints = new ArrayList<Point>();
private void setPointColor(GC g, Point cpoint) {
if (oldpoints.contains(cpoint)) {
g.setForeground(cGreen);
} else if (!oldpoints.contains(cpoint)) {
g.setForeground(cRed);
}
if (cpoint.equals(currentPoint)) {
g.setForeground(cBlue);
oldpoints.add(cpoint);
}
}
Please suggest other medhod, as this one is not efficient and logicful. Thanking you in advance.
I think your solution is a reasonable one, but consider using a Set instead of a list. For example, a TreeSet or HashSet will be able to check for existing entries in a large collection far, far faster (O(log n) for trees and O(1) for hash buckets) than iterating over a list (O(n) - linear time).
private Set<Point> oldpoints = new HashSet<Point>();
I'm working on a game in java, based on the Atari game adventure. I got the basic KeyListener part working fine, but then I added another if statement, using another class, to test if if the player was going to hit a wall, and stopping movement if that was the case. The method I used also used if statements, and when I ran the code, it had MAJOR lag. I tried a while loop first, but that made it lag even worse. Anyway to make this not lag so much? It doesn't seem that complex a program to run, and I still have to add yet another if statement to make be able to move into another room, so I have to do something to massively cut down on the lag.
Here is the class:
class Player extends JPanel implements KeyListener{
private char c = 'e';
int x = 400;
int y = 400;
int mapX = 0;
int mapY = 0;
public Player() {
this.setPreferredSize(new Dimension(800, 500));
addKeyListener(this);
}
public void addNotify() {
super.addNotify();
requestFocus();
}
public void paintComponent(Graphics g) {
super.paintComponent(g);
Environment Layout = new Environment();
Layout.drawRoom(mapX,mapY,g);
g.fillRect(x , y , 20, 20);
}
public void keyPressed(KeyEvent e) { }
public void keyReleased(KeyEvent e) { }
public void keyTyped(KeyEvent e) {
c = e.getKeyChar();
repaint();
Environment Layout = new Environment();
if(Layout.isWall(x,y,c)){}
else{
if (c == 'a'){
x = x - 3;
}
else if (c == 'w'){
y = y - 3;
}
else if (c == 's'){
y = y + 3;
}
else if (c == 'd'){
x = x + 3;
}
}
}
public static void main(String[] s) throws IOException{
JFrame f = new JFrame();
f.getContentPane().add(new Player());
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
f.pack();
f.setVisible(true);
}
}
The draw room method I used in this was just to put the background of the room into place.
Here is the isWall method from the Environment class:
public boolean isWall(int moveX, int moveY, char let){
BufferedImage room = null;
try {
room = ImageIO.read(new File(xNum + "," + yNum + ".png"));
}
catch (IOException e) {
}
int[][] walls = convertImage(room);
boolean blocked = false;
if(let == 'w') {
if(walls[moveY-8][moveX] == -3584){blocked = true;}
}
else if(let == 's') {
if(walls[moveY+20][moveX] == -3584){blocked = true;}
}
else if(let == 'a') {
if(walls[moveY][moveX-5] == -3584){blocked = true;}
}
else if(let == 'd') {
if(walls[moveY][moveX+20] == -3584){blocked = true;}
}
return blocked;
}
the convertImage method just converts the image of the room into an int array, for the value of the colors. -3584 is the color of the walls. It's possible this is what's lagging it, but this seemed like the best way for each room to have the walls done automatically.
I also tried a timer, but either I did that wrong, or it just didn't help.
I can give more of my code if that's needed, but help with this would be much appreciated. I'm relatively new to this kind of stuff, so it's likely I'm missing something big. Thanks.
The lag here is almost certainly not from the if statements. Those are really fast. I think the bigger issue is in isWall. Notice that any time you want to check for whether a wall is present, you
Open a file,
read the file contents,
convert the file contents from an image to a grid of pixels, and
read exactly one pixel.
Reading files from disk is extremely slow compared to looking at values in memory. For example, a regular magnetic hard drive works at around 7200 RPM, so the seek time is measured in milliseconds. On the other hand, your processor can do about a billion operations per second, so other operations take nanoseconds. That means that a disk read is roughly a million times slower than other operations, which is almost certainly where you're getting the lag from!
To fix this, consider rewriting your isWall code so that you only read the file and do the conversion once and, having done that, then just look up the part of the image you need. This converts doing tons of (glacially slow) file reads to one single (slow but inevitable) file read followed by tons of fast memory reads.
You appear to be moving your walls further than you are moving your player.
Is it possible that your player object is getting stuck in a wall there by producing "blocked = true" continuously?
Your character gets +- 3 in every direction, however your walls seem inconsistent and range from 8 up to 20 down to 5 left to 20 right.
This is an extension to #templatetypedef's answer.
Instead of loading the image files upon calling the isWall method, you might want to consider caching all of the walls on game start.
So I am thinking;
have a HashMap data structure keyed by <String, Integer>. Where String is your coordinates. E.g. coordinate string = "100,238"
parse all the .png image files in the directories and store the coordinates as key and the value can just be any dummy value like 1 or 2.
Then when isWall() is invoked. Given the X and Y coordinate, build the coordinate string as mentioned in point 1 and check if the key exists. If it does then we know it is a piece of wall else not.
This should drastically reduce the I/O disk contention.
In future, if you would like to extend the solution to incorporate APIs like isTreasureChest() or isMonster(). It can be extended by building a immutable class call "Room" or "Tile" to represent the object. Then modify the HashMap to take in <String, Room>.
I'm making a game where i need to give my objects collision, but i have many fast small objects and normal collision algorithms (Intersection of shapes and such) do not work, because the position+speed iteration advances the walls and there's never actually an Intersection.
So i've started constructing my own (Maybe it already exists but i didnt see it anywhere) collision algorithm based on saving the last position the object was.
Please see the following image:
The idea is demonstrated in frame 1 and 2 of the image. Basicly by checking if there's a wall between the left side of the last rectangle and the right side of the new rectangle, i never skip zones while i check collision, and there's no risk of skipping a wall (so i thought).
This is the code of the algorithm:
private void bounce(GameElement b, Terrain t)
{
Rectangle tR = t.getRectangle();
int tRleft = tR.x;
int tRright = tR.x+tR.width;
int tRup = tR.y;
int tRdown = tR.y+tR.height;
Rectangle bRnow = b.getRectangle();
int bRnowLeft = bRnow.x;
int bRnowRight = bRnow.x+bRnow.width;
int bRnowUp = bRnow.y;
int bRnowDown = bRnow.y+bRnow.height;
Rectangle bRlast = b.getRectangleLast();
int bRlastLeft = bRlast.x;
int bRlastRight = bRlast.x+bRlast.width;
int bRlastUp = bRlast.y;
int bRlastDown = bRlast.y+bRlast.height;
boolean leftRight = false, rightLeft=false, upDown=false, downUp=false;
boolean betweenX = false, betweenY = false;
if(bRnow.x>bRlast.x)leftRight=true;
if(bRnow.x<bRlast.x)rightLeft=true;
if(bRnow.y>bRlast.y)upDown=true;
if(bRnow.y<bRlast.y)downUp=true;
if(bRlastRight>tRleft && bRlastLeft<tRright) betweenX = true;
if(bRlastDown>tRup && bRlastUp<tRdown) betweenY=true;
if(leftRight)
if((tRleft>bRnowLeft || tRleft>bRlastLeft) && tRleft<bRnowRight && betweenY)
{
b.setX(tR.x-bRnow.width - 1);
}
if(rightLeft)
if((tRright<bRnowRight || tRright<bRlastRight) && tRright>bRnowLeft && betweenY)
{
b.setX(tR.x+tR.width + 1);
}
if(upDown)
if((tRup>bRnowUp || tRup>bRlastUp) && tRup<bRnowDown && betweenX)
{
b.setY(tR.y-bRnow.height - 1);
}
if(downUp)
if((tRdown<bRnowDown || tRdown<bRlastDown) && tRdown>bRnowUp && betweenX)
{
b.setY(tR.y+tR.height + 1);
}
}
Its called bounce because its not really organized atm, i still have to think how to structure the algorithm so it becomes more generalized and pratical (Would appreciate help on that too)
This way of doing collision has one bug at the moment which is seen in image 3 (sorry for drawing circles, they are supposed to be squares) because FAST objects still pass diagonals :/ On the other hand, direct hits on walls are pretty neat.
How could i improve, optimize and organize this algorithm? Or is there any better algorithm and im just thinking too much for nothing? I appreciate your help.
Axis aligned bounding box trees are usually well suited to detecting object collisions. Here is a tutorial with some code - its examples are for 3D collision detection, but the data structure can be easily adapted to 2D collision detection.
I am making a 2d platformer in Swing java, and I am wondering how to reduce the lag I get from it. I mean, it doesnt lag too bad but it is noticable that it slows down sometimes. I have a Swing timer ticking at 12 milliseconds, a cycle function, and a paint function.
public void cycle() {
if (guy.getJumpState() == false) {
if (canExecuteMovement(0, 4)) {
onGround = false;
if (guy.getY() > 300) {
// if you are in the middle, move the platforms.
for (int i = 0; i < platformCount; i++) {
platform[i].setY(platform[i].getY() - 4);
}
} else {
// or just move the guy if not.
guy.moveY(4);
}
} else {
onGround = true;
}
} else {
if (canExecuteMovement(0, -8)) {
if (guy.getY() < 300) {
// if you are in the middle, move the platforms.
for (int i = 0; i < platformCount; i++) {
platform[i].setY(platform[i].getY() + 8);
}
} else {
// or just move the guy if not.
guy.moveY(-8);
}
jumpCount++;
if (jumpCount >= 15) {
jumpCount = 0;
guy.setJumpState(false);
}
} else {
jumpCount = 0;
guy.setJumpState(false);
}
}
if (guy.getDirection() == "left") {
if (canExecuteMovement(-3, 0)) {
if (guy.getX() < 450) {
// if you are in the middle, move the platforms.
for (int i = 0; i < platformCount; i++) {
platform[i].setX(platform[i].getX() + 3);
}
} else {
// or just move the guy if not.
guy.moveX(-3);
}
}
} else if (guy.getDirection() == "right") {
if (canExecuteMovement(3, 0)) {
if (guy.getX() > 450) {
// if you are in the middle, move the platforms.
for (int i = 0; i < platformCount; i++) {
platform[i].setX(platform[i].getX() - 3);
}
} else {
// or just move the guy if not.
guy.moveX(3);
}
}
}
}
public void paint(Graphics g) {
super.paint(g); // something important
Graphics2D g2d = (Graphics2D) g;
// draw platforms
for (int i = 0; i < platformCount; i++) {
if (platform[i].getX() > -50 && platform[i].getX() < 950 && platform[i].getY() > -50 && platform[i].getY() < 650) {
g2d.drawImage(platform[i].getImage(), platform[i].getX(), platform[i].getY(), this);
}
}
// draw guy
g2d.drawImage(guy.getImage(), guy.getX(), guy.getY(), this);
// destroy unneeded processes
Toolkit.getDefaultToolkit().sync();
g.dispose();
}
What can I do to optimize this and cause less lag? When I make a thread for the cycle function itself, the platforms sometimes seperate for a split second. I assume because since the thread is asynchronous, half of it is done while the paint function goes on.
Some loose thoughts (it's been years since I did some animation in Swing), and you didn't posted some compilable code.
Have you tried do paintComponent() --- paint does a lot of other stuff. And then maybe you need to add repaint() to tick function. Every time I reloaded paint it enden in a mess.
Also try increasing tick time --- youll waste less time repaiting.
Also I assume you are doing ticks by Timers.
I have no idea why you dispose graphics object
Also try just dropping sync (Ive done animations that work on many oeses without it) Toolkit.getDefaultToolkit().sync()
If it doesn't help use profiler to find a bottleneck. Visual VM is quite nice. Also Visual VM is part of the jdk for some time --- just go into bin folder and launch jvisualvm.
EDIT: (thread issues)
Some people suggested using threads --- which I diasgree. If you want do some work outside EDT please use SwingWorker
I assume you are not calling paint() but just call repeaint(). If you do call paint() (whatever black magic you also make to make it work) please just call repaint() that will schedule repaing on appropriate time.
First of all, this bit here is a problem:
// destroy unneeded processes
Toolkit.getDefaultToolkit().sync();
g.dispose();
In general, disposing a resource you did not create is probably a bad idea. In this specific case, the Graphics passed into paint() is probably used by all other components in the hierarchy, so this could cause really odd results.
Calling Toolkit.sync() here is I think your attempt to eliminate the tearing you were seeing when moving things in the background. But all that it does is to flush any pending draw instructions. That has no effect here because you are probably drawing to a back-buffered Swing component that will be drawn fully later.
The correct way to eliminate tearing is to perform any updates on the event thread, so that you are not changing the screen data while drawing it. One simple way to implement this would be to have your timer just call repaint(), and have the paint() method call cycle() before doing anything.
For dealing with lag, one solution might be to allow a variable frame rate. Instead of moving everything a fixed distance each frame, calculate the time since the last frame and move everything accordingly.
I would create your variables outside the method so that it is not being created every time you call that method. The best way to program games is to re-use things instead of destroying and creating because destroying & creating cost a lot of computing power.
Graphics2D g2d = (Graphics2D) g; <---declare it outside your method.
And also try to find redundant conditionals. I saw one where you say (if direction right then ..., else if direction left ...); just say (if direction right then ... else ...). Conditionals do not cost much but when you're calling that conditional 1000 times a second I think it adds up. (idk though, but I do it just in case and for making things fluid)
Where you say setjumpstate(false) it's redundant because no matter what, it is executed - just move it outside the conditional.