I've been trying various ways of creating a two-dimensional tile-based game for a few months now. I have always had each tile be a separate object of a 'Tile' class. The tile objects are stored in a two-dimensional array of objects. This has proven to be extremely impractical, mostly in terms of performance with many tiles being rendered at once. I have aided in this by only allowing tiles within a certain distance of the player being rendered, but this isn't that great either. I have also had problems with the objects returning a null-pointer exception when I try to edit the tile's values in-game. This has to do with the objects in the 2D array not being properly initialized.
Is there any other, simpler way of doing this? I can't imagine every tile-based game uses this exact way, I must be overlooking something.
EDIT: Perhaps LWJGL just isn't the correct library to use? I am having similar problems with implementing a font system with LWJGL... typing out more than a sentence will bring down the FPS by 100 or even more.
For static objects (not going anywhere, staying where they are) 1 tile = 1 object is OK. That's how it was done in Wolf3d. For moving objects you have multiple options.
You can, if you really really want to, store object sub-parts in adjacent cells/tiles when an object isn't contained fully within just one of them and crosses one or more cell/tile boundaries. But that may be not quite handy as you'd need to split your objects into parts on the fly.
A more reasonable approach is to not store moving objects in cells/tiles at all and process them more or less independently of the static objects. But then you will need to have some code to determine object visibility. Actually, in graphics the most basic performance problems come from unnecessary calculations and rendering. Generally, you don't want to even try to render what's invisible. Likewise, if some computations (especially complex ones) can be moved outside of the innermost loops, they should be.
Other than that it's pretty hard to give any specific advice given so little details about what you're doing, how you're doing it and seeing the actual code. You should really try to make your questions specific.
A two-dimensional array of Tile objects should be fine........ this is what most 2D games use and you should certainly be able to get good enough performance out of OpenGL / LWJGL to render this at a good speed (100FPS+).
Things to check:
Make sure you are clipping to only deisplay the visible set of tiles (According to the screen width and height and the player's position)
Make sure the code to draw each tile is fast... ideally you should be drawing just one textured square for each tile. In particular, you shouldn't be doing any complex operations on a per-tile basis in your rendering code.
If you're clever, you can draw multiple tiles in one OpenGL call with VBOs / clever use of texture coordinates etc. But this is probably unnecessary for a tile-based game.
Related
Similar to the game Factorio im trying to create "3D" terrain but of course in 2D Factorio seems to do this very well, creating terrain that looks like this
Where you can see edges of terrain and its very clearly curved. In my own 2D game Ive been trying to think of how to do the same thing, but all the ways I can think of seem to be slow or CPU intensive. Currently my terrain looks like this:
Simply 2D quads textured and drawn on screen, each quad is 16x16 (except the water thats technically a background but its not important now), How could I even begin to change my terrain to look more like a Factorio or other "2.5D" games, do they simply use different textures and check where the tile would be relative to other tiles? Or do they take a different approach?
Thanks in advance for your help!
I am a Factorio dev but I have not done this, so I can only tell you what I know generally.
There is a basic way to do it and then there are optional improvements.
Either way you will need two things
Set of textures for every situation you want to handle
Set of rules "local topology -> texture"
So you have your 2d tile map, and you move a window across it and whenever it matches a pattern, you apply an appropriate texture.
You probably wouldn't want to do that on the run in every tick, but rather calculate it all when you generate the map (or map segment - Factorio generates new areas when needed).
I will be using your picture and my imba ms paint skills to demonstrate.
This is an example of such rule. Green is land, blue is water, grey is "I don't care".
In reality you will need a lot of such rules to cover all cases (100+ I believe).
In your case, this rule would apply at the two highlighted spots.
This is all you need to have a working generator.
There is one decision that you need to make here. As you can see, the shoreline runs inside the tile, not between tiles. So you need to chose whether it will run through the last land tile, or the last water tile. The picture can therefore be a result of these two maps (my template example would be from the left one):
Both choices are ok. In fact, Factorio switched from the "shoreline on land" on the left to the "shoreline on water" on the right quite recently. Just keep in mind that you will need to adjust the walking/pathfinding to account for this.
Now note that the two areas matched by the one pattern in the example look different. This can be a result of two possible improvements that make the result nicer.
First is that for one case you can have more different textures and pick a random one. You will need to keep that choice in the game save so that it looks the same after load.
Another one is more advanced. While the basic algorithm can already give you pretty good results, there are things it can't do.
You can use larger templates and larger textures that span over several tiles. That way you can draw larger compact pieces of the terrain without being limited by the fact that all the tiles need to be connectable to all (valid) others.
The example you provided are still 2D textures (technically). But since the textures themselves are 'fancy 3D', they appear to be 3D/2D angled.
So your best bet would be to upgrade your textures. (and add shadow to entities for extra depth).
Edit:
The edges you asked about are probably layed-out by checking if a 'tile' is an edge, and if so it adds an edge-texture on top the background. While the actual tile itself is also a flat image (just like the water). Add some shadow afterwards and the 3D illusion is complete.
I hope this answers your question, otherwise feel free to ask clarification.
I decided to make a 2d game in Java (using the slick2d library and MarteEngine) and I attempted to do it without a tiled map. It seems like my upcoming tasks are going to be very difficult without having a tiled map. Those tasks are pathing and collisions (between buildings and players/NPCs).
Is it going to be nearly impossible to easily implement a pathfinding and collisions system? I suppose I could always manually create a grid in the game but that might become kinda messy considering I'd have to move it since I have a functional camera.
Also, by collisions I mean units walking into each other and becoming a single unit. I guess that could be categorized under pathing but I have no solution to fixing them from overlapping.
Any ideas are appreciated!
A lot of games still divide the map into tiles even if it isn't a tile-based game.
The reason is that you can do collision detection by checking whether an object is overlapping any of the objects in its current tile or any of the neighbouring tiles. As long as your objects are no larger than the tiles, this collision detection scheme is guaranteed to work out all possible collisions.
EDIT
If you have exisiting graphics that are not tile-based, it is still worth using this kind of "virtual" grid for collision detection etc. You can mark specific grid squares as being wholly or partially "blocked" if you want to detect collisions with map features and suchlike.
So, I'm creating a 2d top-down game in Java.
I'm following instructions from Java 2D: Hardware Accelerating - Part 2 - Buffer Strategies to take advantage of hardware acceleration.
Basically, what I'm thinking is this:
I'd like to be able to easily add more sections to the map. So I'd rather not go the route suggested in a few of the tutorials I've seen (each map tile has an adjacency list of surrounding tiles; beginning with a center tile, populate the screen with a breadth-first search).
Instead, my idea would be to have screen-sized collections of tiles (say 32x32 for simplicity), and each of these screen "chunks" would have an list referencing each adjacent collection. Then, I would create a buffer for the current screen and the 8 adjacent screens and draw the visible portion in the VRAM buffer.
My question is, would this be a correct way to go about this, or is there a better option? I've looked through quite a few tutorials, but they all seem to offer the same (seemingly high maintenance) options.
It would seem this would be a better choice, as doing things at the tile level would require 1024 times as many adjacency lists. Also, the reason I was considering putting only the visible portion in VRAM, while leaving the "current" screen and its adjacent screens in standard buffers was because I'm new to hardware acceleration and am not entirely sure how much space is acceptable to assume to be available. Because Java attempts to accelerate standard buffers anyways, it should theoretically be as fast as putting each in VRAM?
Any and all suggestions are welcome!
I haven't looked at any of the popular tile-based game engines, but I'd consider using the fly-weight pattern to render only the tiles that are visible in the viewport of a JScrollPane. JTable is both an example and a usable implementation.
Addendum: One advantage of the JTable approach is view-model separation, which allows one to relegate the acquisition of tile-related resources to the model. This makes it easier to optimize without having to change the view.
Even without scroll bars, one can leverage scrollRectToVisible() by extending JComponent or an appropriate subclass. The setDoubleBuffered() method may be helpful, too.
Im making a game in Java with a few other people but we are stuck on one part of it, making the collision detection. The game is an RPG and I know how to do the collision detection with the characters using Rectangles, but what I dont know how to do is the collision detection for the maps. What I mean by that is like so the character cant walk over trees or water and that stuff but using rectangles doesnt seem like the best option here.
Well to explain what the game maps are gonna look like, here is an example http://i980.photobucket.com/albums/ae287/gordsmash/7-8.jpg
Now I could use rectangles to get bounds and stop the player from walking over the trees and water but that would take a lot of them.
But is there another easier way to prevent the player from walking over the trees and obstacles besides using Rectangles?
Here's a simple way but it uses more memory and you do the work up front... just create a background collision mask that denotes the permissible areas for characters to walk on in a binary form. You can store that in some sort of compressed bitmap form. The lookup then is very simple and very quick.
Rectangle collision detection seems to make sense; However, alternatively you may also try sphere-sphere collision detection, which can detect collision much quicker. You don't even need a square root for distance computations since you can compare the squared distances to see if the spheres overlap. This is a very fast method, and given the nature of your game could work very well.
ALSO! Assuming you have numerous tiles which you are colliding against, consider some method of spacial partitioning. Let me give you an easy example - subdivide your map into several rectangles (http://www.staff.ncl.ac.uk/qiuhua.liang/Research/Pic_research/mine_grid.jpg) and then depending on which rectangular area your player is currently residing in - check collision only against the tiles which are located within that area.
You may take it a step further - if you have more tiles in any given area than the threshold that you set - subdivide that area further to make more smaller areas within it.
The idea behind such subdivision is called Quadtree, and there is a huge quantity of papers and tutorials on the subject, you'll catch on very quickly.
Please let me know if you have any questions.
There are many solutions to this type of problem, but for what you're doing I believe the best course of action would be to use a tile engine. This would have been commonly used in similar games in the past (think any RPG on the SNES) and it provides you with a quick and easy means of both level/map design and collision detection.
The basic concept of a tile engine is that objects are stored in a 2D array and when your player (or any other moving game entity) attempts to move into a new tile you perform a simple check to see if the object in that tile is passable or not (for instance, if it's grass, the player may move; if it's a treasure chest, the player cannot move). This will greatly simplify checking for collisions (as a naive check of a list of entities will have O(n^2) performance). This picture might give you an idea of what I'm talking about. The lines have been added to illustrate a point, but of course when you're playing the game you don't actively think of everything as being composed of individual 32x32 pixel tiles.
While I don't personally have any experience with tile engines in Java, it looks like Mappy supports Java, and I've heard good things about PulpCore. You're more than welcome to create your own engine, of course, but you have to decide if your effort is better spent reinventing the wheel (but, of course, it will be your wheel then, and that is rather satisfying) or spend your time making a better game.
I'm trying to develop side scrolling game for android involving many many textures so I was thinking if I could create a separate layer, all a single unique color (very similar to a green screen effect) make a collidable and make it invisible to the player.
(foreground layer) visual Image
(2nd layer)collidable copy of foreground layer with main character
(3rd layer)Background image
I not sure if this is possible or how to implement it efficiently, the idea just came to me randomly one day.
Future regards, Thanks
I assume your game is entirely 2D, using either bit-blits or quads (two 3D triangles always screen-aligned) as sprites. Over the years there have been lots of schemes for doing collision detection using the actual image data, whether from the background or the sprite definition itself. If you have direct access to video RAM, reading one pixel position can quickly tell if you've collided or not, giving pixel-wise accuracy not possible with something like bounding boxes. However, there are issues greatly complicating this: figuring out what you've collided with, or if your speed lands you many pixels into a graphical object, or if it is thin and you pass through it, or how to determine an angle of deflection, etc.
Using 3D graphics hardware and quads, you could potentially change render states, rendering in monochrome to an off-screen texture, yielding the 2nd collidable layer you described. Yet that texture is then resident in graphics memory, which isn't freely/easily accessible like your system memory is. And getting that data back/forth over the bus is slow. It's also costly, requiring an entire additional render pass (worst case, halving your frame rate) plus you have all that extra graphics RAM used up... all just to do something like collision-detect. Much better schemes exist, especially using data structures.
It's better to use bounding boxes, or even a hierarchy of sub-bounding boxes. After that, you can determine if you've landed on the other side of, say, a sloped line, requiring only division/addition operations. Your game already manages all the sprites you're moving, so integrate some data structures to help your collision detection. For instance, I just suggested in another thread the use of linked lists to limit the objects you must collision-detect against one another.
Ideas like yours might not always work, but your continual creative thinking will lead to ones that do. Sometimes you just have to try coding them to find out!