I'm creating "tile game"
The question I would like to ask is: let's say that my map is gonna be 5000*5000 tiles and as you can see I already got some enemies there (two red piles-slimes :D) the problem is that I would like to have cca one enemy per 500 tiles so 5000*5000/500 which results in about 50000enemies which is impossible to render at once so I've got rectangle object which holds the actual screen that player can see and if the hitbox of the "slime" intersects the rectangle then Im rendering it, but the problem is that I still have to loop through each of those slimes to see whether their hitbox isnt in the screen rectangle after the player moved, is there anyone who ever had similar problem ? If so could you tell me your solution ?
but the problem is that I still have to loop through each of those
slimes to see whether their hitbox isnt in the screen rectangle after
the player moved,
Looping through some slimes when the player moves is normal or rather acceptable but looping through all slimes is not.
You should probably maintain a structure where you know for each tiles area the enemies that are present on.
A tiles area should gather a certain number of tiles but beware you should find/adjust its size to make it not too small (you lose interest of that as you have to inspect many of them) and not too big either (you will loop on many enemies that may be too far).
The overall idea is so checking the enemy presence only for tiles area close form the player. A structure such as Map<TilesZone, List<Enemy>> may make sense or maybe TreeMap<TilesZone, List<Enemy>> to benefit from NavigableMap interface that could be helpful in your use case.
Related
on a 100x50 orthogonal tilegrid with 32x32 tiles, i created some animated Units, which are moved by A* (like in many strategy games usual) with a rightclick on the mouse.
The collision detection works by using a two dimensional booleanarray i gave the grid in the constructor and this says whether a tile is an obstacle or not.
Thats what i have so far and it works.
I am now figuring out, some Kind of Units coordinationsystem, which simply doesnt allows the Units to walk into each other. All of this just should be in this 32x32 tilesized RASTER not more for the moment.
I just thought this should be easy, but the grid is loaded once just like the obstacles, while the Units positions are always different and the Problem here is, that if i define each unit as an obstacle at Runtime, the obstacle at its Position stays stored in the gridarray and it stay some Kind of invisible obstacle, although it shouldnt be one. The result is, that the unit cant go the way back, where it cames from. Another Problem is of Course, that a unit can stand still or move arround(so far) and if it moves arround ist not rastered anymore.
My question now is: How can i implement a movable obstacle or do i have to implement a separate collision detection for my Units here?
PS: The Programm is quite big and i dont like to post the whole Code, although that would make all easier for u guys to help me, but if somebody understand what i mean, i can post the relevant Code snippets here on the Forum.
I am making a 2D game in JavaFX and when detecting collisions, I am getting rather inaccurate results due to the player sprite being set as the fill of a rectangle and therefore not having the intended borders. Is there a way I could make my own shape so thatI could get as accurate as possible?
Another idea I had is checking if the pixel that collided was transparent and then not ending the game if it was. Does anyone know of a way I can get the coordinates of the pixel that collides so that from there I can use PixelReader to check?
If anyone knows a better way, please let me know!
Thanks,
Ethan
There are different ways to do this. Here is one way I have used with good success. I would make hit boxes, that were themselves rectangles. Then during collision detection, I would iterate through all the hit boxes to see if they collided with the flying projectile's hit boxes.
What this allows you to do is fill in complex shapes with smaller rectangles. For example a plane would have one long horizontal rectangle and one smaller rectangle crossing at the middle.
Currently I am using libGDX. In libGDX I use their Polygon object as stated here. https://stackoverflow.com/a/28540488/1490322 I have not seen similar functionality in JavaFX, but it would not be hard to copy what libGDX is doing into JavaFX code... their code is open sourced.
So I had a quick question. I'm currently making a small game in java and I wanted to experiment with hiding the player behind fake 3D objects on the screen (Isometric drawing). Unfortunately I can't post a picture (Not enough rep). Basically it's a 3D block that is 32 by 48 that gives an illusion that it's 3D by having half of it a lighter color and the other half a darker one. The player is the same size as the block and can move freely around the map of these 'blocks'. If the player moves behind a block, it's bottom part is hidden behind it. The opposite when it moves in front, covering the non-player block. Now I made an example program in GameMaker Studio just to test it out. To make it work in GM, I made a script for each sprite that was one line of code:
depth = y * -1
This causes the bottom part of the player to 'hide' behind the blocks when it moves behind them. I looked into it a bit on GM's wiki and it's pretty much changing the 'depth' of the instances. Now my question is, how would I do something like this in Java?
P.S. This is not in a diamond. It is in a straight 2D world (looking 45 down towards objects from front).
EDIT:
Here are some pictures of the GameMaker version:
Player Outside
Player Inside
Read about drawing isometric worlds.
Read about Java and isometric development.
Thanks to Kayaman for solving the problem:
If you draw your player first, then a wall on the block south of it, the top half of the wall will mask the bottom half of the player. So no, you don't need to draw halves separately. This means of course that you need to draw the player at the same time as the map, so you can't first draw the map and then the player.
Just for future use, layering images in java is determined by the order in which they are added. This was the exact answer I was looking for. The GM code was GameMaker's way of setting the order in which the images were added to the screen.
Thanks to everyone for the help!
I have made threads in the past about similar questions but because of my lack of detail the answers have not really been related to what I needed so I am going to try explain my question in as much detail as I can and hopefully it will be easier for you to understand what I require.
I watched Bucky's slick game tutorials on youtube and made a 2D Java game, the game is basically a 2D player viewed from above (birds eye view) can move around a 2D map with user key input (up, down, left, right). The map the player moves around is very small so that meant boundaries had to be set so that the player could not walk off of the map, to give you a better idea of how this was done, here is the tutorial for setting up the voundries:
http://www.youtube.com/watch?v=FgGRHId8Fn8
The video will also show you exactly what the game is like.
The problem is, these boundaries only require one axis meaning that if the player is walking down you say something like "if player gets to the coordinate (number) on the X axis change the player movement to the opposite direction so that he can not go any further."
Now this creates a problem for me because this only requires one axis so it easy to set up and understand but if you look on the video, on the map there is a house and I want my player not to be able to walk over that also but this deals with 2 dimensions, I have looked at things like rectangle collisions and have seen things relating to them in the other posts but I get confused because I am new to Java and havent really done much with it at the moment apart from watching Bucky's tutorials.
My code at the moment for my game class has got the following methods: init, render and update. So to sum it up I really just want to set up a way of not letting my player walk through the house, I will mention also (I should have mentioned it in my other threads) as I am very new to Java, could you please take a step by step method of showing me how to set up the collisions, I mean even the basics of things like making the rectangle if required.
If my code is required please tell me and I will post it as soon as possible.
Thank you in advance.
You can set up the board as a 2x2 grid of a class that has has property such as 'isBlocked'. By default the edges of the board would have this property set to true to prevent the character from walking off the edge. When you add other obstacles such as a house or a wall the grid position(s) the object occupies would also have the property set to true. Then when moving a character you just check if the grid position the character moves to has the property set to false to see if it's an allowable move. This also makes it quite trivial to save the level data so you can just load them from disk later on.
Two possible options:
Extend Shape or Rectangle or the relevant Slick objects (they should exist IMO) and just check for intersect()
Look for (x1,y1) and (x2,y2) values such that it starts outside and ends up inside.
Assuming you have intersect() methods:
//Grab the previous position
prevPosX = movingobject.X;
prevPosY = movingobject.Y;
//Update the position
movingobject.update();
//Test for collision
if(movingobject.intersects(targetobj)) {
//If it collided, move it back
movingobject.X = prevPosX;
movingobject.Y = prevPosY;
//And reverse the direction
//(might want to do other stuff - e.g. just stop the object)
movingobject.speed *= -1; //Reverse the speed
}
in this case your update class should also add one more condition to look for the house. let say the cooridnates of house(assuming rectanglular house here for other shape just change x and y values) are (x1,y1)(x1,y2)(x2,y2)(x3,y1) you have to add a condition to make sure
x value is not between x1 and x2 and at the same time y value cannot between y1 and y2.
I'm creating an application where I need to model (and display) a large number of 2-dimensional 'balls' (circles) using java. I've started by creating an ArrayList of Circle objects (a class that I defined, which has x/y pixel coordinates of the center of the circle, radius, color, and velocity in the x & y directions). I use a java.util.Timer object with a repeated TimerTask to control the motion of the circles. The circles vary in size from around 10-50 pixel radii.
What I want to happen is have balls fall from the top of the screen (randomly distributed across the x-axis) until they reach the bottom of the screen, which acts like a floor -- ball that reach it stop moving, and balls that reach stopped balls roll downhill on the other balls until they rest at a low/flat point. In the future I might want to make their behaviour a bit more complicated, so I want to create flexible code so I can easily expand. How it works right now is that every time period each circle check to see how close they are to every other circle. If there are no other circles nearby they continue falling normally. If two (or more) circles are close to each other there is code to determine how they will interact.
I have it working perfectly for small numbers of circles (< 200), but when I get larger numbers of circles (> 400) it starts slowing down significantly. I'm sure I can optimize some of the logic to make the comparisons a bit faster, but I was wondering if there are any ways of storing the circle in some structure besides an unorganized ArrayList that would let me easily find circles that are close to each other, so I don't have to do the N^2 operation of comparing each circle to every other one and, instead, just compare a circle to the 5-10 circles closest to it. For instance, I've considered using a 2D array to represent every pixel (or maybe square of 5x5 pixels) and store a circle where its center lies (so I could check if there are circles in any of the nearby cells, and ignore the rest). However, this still seems pretty inefficient as if I'm using a 800x1000 pixel canvas with 500 circles there would be a TON of empty spaces in the 2d array that I'd waste time checking. I've also considered some sort of hashmap, but I haven't thought of a great way to use that either.
So, can anyone think of an efficient way to store these circles that corresponds to it's location in 2d space and makes it easy to find nearby circles? Thanks in advance!
You can use a QuadTree to find close neighbours. Or you can simply sort by one direction, which would be far easier to implement and should still allow you to reduce the number of candidate neighbours to a small window.
Perhaps your idea of a 2D array is not so crazy. What I think you want is one List of all your circles, and a 2D array that would reference the circles also. So at each time, you can iterate over your List<Circle> to check each one. Each Circle has x,y coords and you only have to loop on your array for (x,y +/- 5). There is no need to check the whole possible space for Circles, because you already are keeping track of each Circle's center. Just grab the center, and check around it for other circles.