• Advertisement
Sign in to follow this  

Unity How to update tiles based on their neighbours

This topic is 2550 days old which is more than the 365 day threshold we allow for new replies. Please post a new topic.

If you intended to correct an error in the post then please contact us.

Recommended Posts

Hello community i hope you can help me on this one.
I have a large hexagonal tile-map (150k tiles now might be more in future). I am working on an ecosystem simulation. Every hex has information about it's current state, and associated variables (like fertility). Tiles should be updated according to their neighboring tiles. I am facing some design and implementation problems here.
First problem is how to handle updating of two neighboring tiles. Let's say we have a tile. It's type is grass and it's fertility is 0.8, one neighbor is river, other is sand. River should rise grasses fertility, and sand should lower it, gradually until this system is balanced. If grasses fertility should drop under a certain threshold, that tile should change to sand (for example). How to design this situation in spirit of good oop.
Problem is I don't know what type is my neighbor, and so i don't know how to react to it. I could use something like double dispatch (but would two polymorphic calls incur too much overhead when world gets large?), or i could use some kind of ID system, and a switch statement. That way code could get pretty messy, as there will be more than 10 different types of tiles, and it would be nice to be able to add more later on.
Second problem is how to update a large system. Updating so much tiles could drop my frame-rate so I figured that it should be done asynchronously in a different thread. This is a big issue for me because i am a total threading noob. My idea is that worker thread updates once everything, then signals the main thread, main thread detects changes and accordingly displays results (if grass is no longer grass make it a dirt).
Also is there a way to organize my data to lower cache misses. I at first used bfs algorithm to traverse entire map, but that was about 20% slower than traversing them the way they are stored in memory. Problem with updating is that i need to access neighbors data that might bee "too far" in memory.

Any kind of help is mucho appreciato. Ideas, good design principles and code are all welcome.

Share this post

Link to post
Share on other sites
If you can generalize the type of tiles interactions, you may get away by not creating a class per type. You could have your tiles provide a modification factor to various properties and make an average and then update your tile. For example, sand could reduce fertility by 0.01 every update and river increase it by 0.01, balancing themselves. You then wouldn't need to know if your neighbor is a river or sand, just how it affects your fertility.

As for your threading problem, you could simply split your tiles in chunks and split them among your worker threads instead of doing your current loop through all tiles. I wouldn't have the update be done in parallel or you will have all sorts of fun problems to deal with later on.

Share this post

Link to post
Share on other sites
As for my threading problem what kind of problems could i get into? Also could you give me a word or two about worker thread method?

About tiles, you are right we could take some time to define our abstractions better, but lets say just hypotheticaly that i have to leave some room for adding new tile types that would break current hierarchy. What would be my approach in this case. (number of tiles and fast interaction still stand)

Sorry for the lack of comment but im on my mobile :/.

Share this post

Link to post
Share on other sites
You would lose determinism when compared to single-threaded code if you use a fixed timestep approach. For example, if your update loop is :
- updateEcosystem()
- doOtherStuff()

If you take out updateEcosystem() and place it in a concurrent thread, doOtherStuff() is no longer guaranteed to work with the up to date data. It may or may not be up to date and may become up to date in the middle of the function. That means you can no longer rely on the ecosystem being up to date in your algorithms. This is where bugs come from.

What you can do instead in the updateEcosystem() function is split all the tiles into chunks. Then you send the chunks to your worker threads and wait until they complete before exiting the function. That way, you retain the same determinism than with single threaded code.

For your tiles, I'm not sure I understand the problem. It seems to me the tiles can be abstracted with a set of values from 0 to 1 and each type affects its neighbors' value in some way, probably by trying to create uniformity. If you must have more complex logic, why not keep the type as a variable and centralize all processing in some common function? You can compare the types directly without calling polymorphic functions and all that. It's not really OOP, but if that's really your bottleneck, you may have to break some rules. It's too vague to properly answer.

Share this post

Link to post
Share on other sites
What you're implementing is essentially a cellular automata. Each cell will transition to a new state, based on its current state and that of its neighbors. Automata get a little more complex when you introduce supplementary data such as the "fertility" value you mention, but it's still possible. Let's assume you have a single integer value "F" for each cell in addition to its state "S". The F-value can have different interpretations depending on its state; say, for city tiles F would be population, and for farmland tiles F would be fertility.

In these terms, you need to define the transition function that takes as input current S, current F, and current S of each adjacent tile, and outputs a new S and new F value. Now, in whatever ways you like, you need to work out your rules and define the transition functions. Keep them simple, and have them generate a large lookup table.

Finally, because a cellular automata updates atomically from one step to another, you need to keep two copies of your grid; one "current", and one "updated". After updating, swap them, making the "updated" into "current" and vice-versa. Now you can have any number of worker threads running on your grid, in whatever order ends up being best optimized; they cannot interfere with eachother, because they all read from one grid and write to non-overlapping portions of another grid.

Share this post

Link to post
Share on other sites
Sign in to follow this  

  • Advertisement
  • Advertisement
  • Popular Tags

  • Advertisement
  • Popular Now

  • Similar Content

    • By Nio Martinez
      I'll be buying a new laptop as my workstation for building games, Mostly 3D but not hard core. 
      I'm stuck at choosing between these 2 specs below. Does this really matter and if so, can some one tell my how and why it matters. 
      Intel core i5-8250U (8th gen Kabylake refresh)(6 MB Smart Cache, 1.6 GHz Base with Turbo Boost up to 3.4 GHz) 4 cores 8 threads
      RAM 8 GB DDR4 (2400 MHz)
      GPU 2 GB DDR5 Nvidia MX150 256 bit
      SSD: yes
      Intel core i7-7500U 2.70GHz Base Processor (4M Cache, up to 3.50 GHz Boost) 2 Cores, 4 Threads
      RAM 4 GB DDR4 (1800 MHz)
      GPU 2 GB DDR5 Nvidia GeForce 940MX 256 bit
      SSD: No
    • By Manuel Berger
      Hello fellow devs!
      Once again I started working on an 2D adventure game and right now I'm doing the character-movement/animation. I'm not a big math guy and I was happy about my solution, but soon I realized that it's flawed.
      My player has 5 walking-animations, mirrored for the left side: up, upright, right, downright, down. With the atan2 function I get the angle between player and destination. To get an index from 0 to 4, I divide PI by 5 and see how many times it goes into the player-destination angle.

      In Pseudo-Code:
      angle = atan2(destination.x - player.x, destination.y - player.y) //swapped y and x to get mirrored angle around the y axis
      index = (int) (angle / (PI / 5));
      PlayAnimation(index); //0 = up, 1 = up_right, 2 = right, 3 = down_right, 4 = down

      Besides the fact that when angle is equal to PI it produces an index of 5, this works like a charm. Or at least I thought so at first. When I tested it, I realized that the up and down animation is playing more often than the others, which is pretty logical, since they have double the angle.

      What I'm trying to achieve is something like this, but with equal angles, so that up and down has the same range as all other directions.

      I can't get my head around it. Any suggestions? Is the whole approach doomed?

      Thank you in advance for any input!
    • By devbyskc
      Hi Everyone,
      Like most here, I'm a newbie but have been dabbling with game development for a few years. I am currently working full-time overseas and learning the craft in my spare time. It's been a long but highly rewarding adventure. Much of my time has been spent working through tutorials. In all of them, as well as my own attempts at development, I used the audio files supplied by the tutorial author, or obtained from one of the numerous sites online. I am working solo, and will be for a while, so I don't want to get too wrapped up with any one skill set. Regarding audio, the files I've found and used are good for what I was doing at the time. However I would now like to try my hand at customizing the audio more. My game engine of choice is Unity and it has an audio mixer built in that I have experimented with following their tutorials. I have obtained a great book called Game Audio Development with Unity 5.x that I am working through. Half way through the book it introduces using FMOD to supplement the Unity Audio Mixer. Later in the book, the author introduces Reaper (a very popular DAW) as an external program to compose and mix music to be integrated with Unity. I did some research on DAWs and quickly became overwhelmed. Much of what I found was geared toward professional sound engineers and sound designers. I am in no way trying or even thinking about getting to that level. All I want to be able to do is take a music file, and tweak it some to get the sound I want for my game. I've played with Audacity as well, but it didn't seem to fit the bill. So that is why I am looking at a better quality DAW. Since being solo, I am also under a budget contraint. So of all the DAW software out there, I am considering Reaper or Presonus Studio One due to their pricing. My question is, is investing the time to learn about using a DAW to tweak a sound file worth it? Are there any solo developers currently using a DAW as part of their overall workflow? If so, which one? I've also come across Fabric which is a Unity plug-in that enhances the built-in audio mixer. Would that be a better alternative?
      I know this is long, and maybe I haven't communicated well in trying to be brief. But any advice from the gurus/vets would be greatly appreciated. I've leaned so much and had a lot of fun in the process. BTW, I am also a senior citizen (I cut my programming teeth back using punch cards and Structured Basic when it first came out). If anyone needs more clarification of what I am trying to accomplish please let me know.  Thanks in advance for any assistance/advice.
    • By Yosef BenSadon
      Hi , I was considering this start up http://adshir.com/, for investment and i would like a little bit of feedback on what the developers community think about the technology.
      So far what they have is a demo that runs in real time on a Tablet at over 60FPS, it runs locally on the  integrated GPU of the i7 . They have a 20 000 triangles  dinosaur that looks impressive,  better than anything i saw on a mobile device, with reflections and shadows looking very close to what they would look in the real world. They achieved this thanks to a  new algorithm of a rendering technique called Path tracing/Ray tracing, that  is very demanding and so far it is done mostly for static images.
      From what i checked around there is no real option for real time ray tracing (60 FPS on consumer devices). There was imagination technologies that were supposed to release a chip that supports real time ray tracing, but i did not found they had a product in the market or even if the technology is finished as their last demo  i found was with a PC.  The other one is OTOY with their brigade engine that is still not released and if i understand well is more a cloud solution than in hardware solution .
      Would there  be a sizable  interest in the developers community in having such a product as a plug-in for existing game engines?  How important  is Ray tracing to the  future of high end real time graphics?
    • By bryandalo
      Good day,

      I just wanted to share our casual game that is available for android.

      Description: Fight your way from the ravenous plant monster for survival through flips. The rules are simple, drag and release your phone screen. Improve your skills and show it to your friends with the games quirky ranks. Select an array of characters using the orb you acquire throughout the game.

      Download: https://play.google.com/store/apps/details?id=com.HellmodeGames.FlipEscape&hl=en
  • Advertisement