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Dev diary number seventeen : Bitwise Tilemapping

Posted by Germain on 09 Jun 2012 / 34 Comments



Jun
9
2012
 34
Huh?

Woah. Friday already? Seems like I was writing last week’s blog yesterday. Geez, time really has a way of sneaking up on you.

We spent this week very focused, touching up several bugs mostly, and working on the trailer.

Here’s a list of what we did this week:

  • Completed the implementation of ladders in the game. Before this week, ladders could not be added at runtime, which meant that they could not be created in the build, and could not be placed by Bricktrons. But now, ladders can be created and destroyed without divine intervention. Hurray!
  • Arrows now stay attached to the characters when they hit. The arrow detects the closest bone in the skeleton hierarchy of the character it hits, and parents itself to that bone. In effect, the arrow seems to lodge itself on the character, and now moves accordingly. Since the target has a tendency to die in the process, we made sure that the arrow stays lodged in the ragdoll as well. This gives some interesting headshot moments, but on the other hand, makes the game slightly less kid-friendly. We will probably add an option to remove those.
  • Added a rudimentary facial animation system to make the Bricktron more expressive. Right now, they can only blink and frown when they get hurt, but eventually, we would like to make them express any kind of feeling, and perhaps even talk, who knows?
  • Started experimenting with shader programming. This is not part of our short-term goals, but we expect that we will need to dabble into custom shader programming to get some specific things done.
  • Made significant progress in the filming of the trailer. One scene in particular was very troublesome: a 30 minutes timelapse of a large castle being built by a small army of Bricktrons. For the entire duration of the scene, we could not intervene, and any significant bug would ruin the entire shot. At 30 minutes per shot, I can safely say that this scene gobbled up several of my days. The result, however is pretty spectacular, and I consider it as the centerpiece for the trailer. I can’t wait to show it!



Tile mapping basics

I was in an interesting conversation last Wednesday with a friend of mine while attending the Mount-Royal Game Society monthly meetup. We were discussing different ways of creating tile mapping in games. We came to the conclusion that, while several methods exist, only a few are truly efficient if you do not have access to layers with transparency.

In a 2d game engine, it is exceedingly easy to create terrain transition because you can overlay textures with opacity maps, and generally do not have to worry about taking into account all the neighbour tile possibility tree.

However, in a 3d game engine, unless you have access to custom shaders, it becomes a real challenge to limit the number of possibilities to a reasonable amount.

The current method we use comes with a rather large number of limitations, but happens to be very lightweight and extremely simple. It is called Bitwise tilemapping.

Inside the red square is a Grass >> Sand tile transition.


I was very fortunate to stumble upon a very good tutorial on this technique when we started developing Castle Story a while ago. But I will attempt to explain it in my own words.

The first thing you need to know about tile mapping is that if you plan on taking diagonal neighbors into account, expect to have a very large possibility tree. Counting diagonals, there are 8 neighbors in a square tilemap. Assuming there are only 2 types of tiles, that means there are 256 possible transitions – waaaaay too much if you plan on drawing those by hand.

That’s a lot of possibilities.


However, notice that I highlighted the few tiles that only take the adjacent neighbour into account : there are only 16 of them. That’s a LOT more manageable than 256, don’t you think?

Allright so let’s say we only have 16 tiles, how do we select which one we should show? This is where the bitwise method comes in handy.

Basically, we check the 4 neighbours one after the other. The order in which we check them is not so important, but let’s say we check them in a clockwise direction, starting from the top. If the neighbour is of a different type than our center tile, we write 0 in our list. If it is the same as the center tile, we write 1. It is important to always write from right to left, because once we are done checking all 4 tiles, we end up with a binary number.

This binary number can then be converted into decimal notation, and we end up with a tile number. This tile, if drawn correctly, should correspond to the shape we are looking for. However, drawing tiles is an art, and this is another subject that is worthy of another tutorial. Maybe some other time.

So, bascially we extrapolate the process to every single tile in the universe, we should end up with something that looks good.

In 3d, it’s a bit more complicated, neighbour tiles can be in any direction, as long as they share an edge. We spent a significant part of our first year of development working out the intricacies of detecting those tile transitions, and applying the right texture mapping to our voxels.

Anyway, that’s pretty much it. I’m not very good at writing tutorials, so I really recommend reading the tutorial I mentioned. It is much better than my own. Anyway, try it yourself! making tile based games can be really fun!



Soundtrack of the week

I have this song in my head. It won’t go away. The cure? Listen to it until you find another song.

Try to guess which one that’s stuck in my head, it has the word “the” in it.


Thanks for reading!

Team Sauropod





34 Comments for Dev diary number seventeen : Bitwise Tilemapping


Rockman209
11 months ago


Woot! Can’t wait for the kickstarter! You’re making excellent progress!

Pablo
11 months ago


I’m spansih!
I need play this game NOW!!!!!!!!! ¬¬ open the indev game, pleaseeeeeeeeee!

thanks :)

Nyan
11 months ago


THIS SONG IS AWESOME! Until they started singing. Thats when I stopped listening. :P

Space Narwhal
11 months ago


YAY!

Space Narwhal
11 months ago


  ?
? ?

PowerBlunt2069
11 months ago


If you guys would spend 1/1000 of the time you spend programming and writing blogs on implementing multiplayer, and a bnet like server, you would be millionaires.

Instead, maybe 20k kids will play this game for a couple weeks and your game will ultimately fail.

But don’t listen to me, i’m just a pot head and it not like I ever play any video games.

    Falconium
    11 months ago


    Not sure if stupid or just stupid. Lay of the pot, it is doing really bad things to your logic and reasoning.

    TrevStar
    11 months ago


    I agree with you. The game looks great and I’ll buy it no matter what but unless there is a competitive multiplayer, I tend to lose interest fairly quickly. I don’t know how hard it is to implement an online multiplayer but I’m sure that a lot of people would play if for much longer.

    Space Narwhal
    11 months ago


    I think it’s funny how none of you have read the FAQ where it says they plan to have a multiplayer….

      Menekis
      11 months ago


      if only you knew how much people don’t read and send me email about it…

      maybe PowerBlunt2069 didn’t understand how indie developpers works and it’s quite understandable because he compare us to BNet.

      So, I’ll try to explain a little how we do work. We prefer to have a great relation with our fan by giving them the best repport of advancement, then we do read suggestions and some of them may be implemented in our game. we want that the community interact directly with de developpment of our game so we could deliver what our fan really want.

      even if it is only 20k that play our game it would be a huge succes for us because we would be able to go trought that wonderfull adventure.

      I’m sorry to see that so many people think it is easy to create a game… let me correct, it is easy to create a game but not easy to create a good one. That’S why we prefer to take our time making things rights. Shipping something awefull would’nt be good publicity neither.

      so yeah there will be a multiplayer. Just be patient about it, we are a very small team, nothing to compare with any of the big company who had ten time the man power that we have.

      this been said, thx everyone for the comments.

      PowerBlunt2069
      11 months ago


      Ok, Ill be honest, I was sarcastically exaggerating and took it too far.
      You have to understand for an avid lover of video games such as myself, too see
      such an awesome game and then be saddened that it may not reach its full potential, devastates me. I dream about playing 3v3′s of this game with my friends, and I guess deep down I am scared it might get overlooked. I want this game, and I know I am not alone.

      thanks i love you.

      Menekis
      11 months ago


      no harms done, just wanted to explain how we are working so people could understand why it does take a lot of time.

    Spacenarwhal
    11 months ago


    Well, maybe Falconium has.

    Gustaf
    11 months ago


    There is going to be multiplayer, dummy >.>

    oregonpinkrose
    11 months ago


    In one post you say you never play video games and in another you say you are an avid video game player.
    I’m beginning to think you might be high.

    Don’t waste time explaining anything to him, Menekis.
    Just keep working on your awesome game so you can take my money.

Dylan
11 months ago


Wow, that bitwise mapping tutorial is really good. I am kinda struggling to understand the concept of the two tilesets though (Water and Grass) let alone, the trinary part.

Zokraytz
11 months ago


Totally got Janglin stuck in my head …THANKS!
Can’t wait for this game, and the video!

James
11 months ago


How is the Kickstarter going? Legal stuff done yet? Can you make a forecast, for when we can help you with funding? Looks like you are making great progress!

PS: This weekend is the Canadiian F1 Grand Prix. You have any favorite team or driver?

    Menekis
    11 months ago


    we are not really fan of F1 and with all the manifestant outside i’m not even sure there will be a Grand Prix this year ;)

Carbonacat
11 months ago


Actually, with rotations you can drastically limit the number of need tiles :
0000 – Isolated
0001 – Dead end (Rotated: 0010 – 0100 – 1000)
0011 – Corner (Rotated: 0110 – 1100 – 1001)
0101 – Pipe (Rotated: 1010)
0111 – 3 ways (Rotated: 1110 – 1101 – 1011)
1111 – 4 ways

16 -> 6 :D

I’m pretty sure the same applies if you want to take in account the diagonals !

Anyway, your technical articles are really interesting, and I can’t wait for the actual game to come up :D

    Germain
    11 months ago


    Yes this is absolutely true. We planned on not rotating our tiles for 2 reasons. First to have a bit of variety in our tiles(16 is better than 6 in that regard), and secondly to streamline the code. These calculations need to be done literally a few thousand times per frame, so the slightest addition in complexity can become really heavy on the CPU. Better to offload some of that complexity in the texture atlas.

    Cheers!

      satamoto
      11 months ago


      Cheers!

pixeltasim
11 months ago


I tried stuffing money into my computer to see if it would magically transfer itself to your banking account. I have bad news and good news. Bad news is that it didn’t go anywhere, good news is that it turns out money really improves airflow.:) Love these dev blogs, as a game dev myself, I really enjoy reading indie dev blogs and how each team solves certain problems. Great tutorials for an aspiring 3d developer!

satamoto
11 months ago


”Made significant progress in the filming of the trailer. One scene in particular was very troublesome: a 30 minutes timelapse of a large castle being built by a small army of Bricktrons. For the entire duration of the scene, we could not intervene, and any significant bug would ruin the entire shot. At 30 minutes per shot, I can safely say that this scene gobbled up several of my days. The result, however is pretty spectacular, and I consider it as the centerpiece for the trailer. I can’t wait to show it!”

NEXT WEEK THE VIDEO YEAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!1

pippoppeo
11 months ago


I think im gona do a german blog for this game. But pls upload a free pre-realease and hold the full game free. Nice job!

Bluey1423
11 months ago


Its funny whenever someone makes a sort “correction” in the comments you guy comment back and correct them again, it feels like you have this all worked out. Great Job!

satamoto
11 months ago


It’s not that I’m impatient it is that could you tell me is possible that the kickstarter is shown next week?
because you sed in your blog:
”Made significant progress in the filming of the trailer. One scene in particular was very troublesome: a 30 minutes timelapse of a large castle being built by a small army of Bricktrons. For the entire duration of the scene, we could not intervene, and any significant bug would ruin the entire shot. At 30 minutes per shot, I can safely say that this scene gobbled up several of my days. The result, however is pretty spectacular, and I consider it as the centerpiece for the trailer. I can’t wait to show it!”

Pls reply to me!

Max392
11 months ago


how much time this game out?

    satamoto
    11 months ago


    Yes !

      satamoto
      11 months ago


      The video about the kickstarter I mean and maybe some information about the game date of relise!

      my english is terrible!!!!!!

      Max392
      11 months ago


      ok :)

      Max392
      11 months ago


      videos are really SHIT!!!!!!!
      videos all surveys!!! are idiot!
      better how much time this game OUT?????????? >.>

Metaknigth
11 months ago


Nice post ! The bitmap tutorial was really awesome.
I can’t wait to see a tutorial on how to draw tiles. I have real trouble with that.

ION 6
11 months ago


hmmm nice job guys.