Rune Skovbo Johansen
Creative Programmer & Designer


Structured Exploration Games

Sep 25, 2014 in ,
I love exploration in games! I like platforming, and I like puzzles, and I can deal with a little combat, but the biggest reason I play games at all is to experience and explore strange, beautiful, mystical places, and unravel the secrets they contain.

Secrets and mystery awaits.

Though many games have elements of exploration, there's not that many I know of that has it as a major focus and really get it right. It doesn't help that some otherwise good exploration games are also very difficult. Being stuck at the same hardcore challenge for ages can get in the way of the joy of exploration.

In order to bring more focus on games where exploration is a major element, I created this Steam curated group:

Exploration Games curated group on Steam

Great games where exploration is a major focus, taking place in worlds that are non-linear yet structured. Also: Secrets and mystery!

Games in this group may have limited but not excessively challenging puzzles, combat, and platforming. They will often have maps.

They may have gated progress based on ability upgrades ("MetroidVania" games), collected items, completed goals, or similar, as long as the progress is not mainly linear.

The word "structured" is also important. The group is not for games that allow you to dig or build anywhere, since it's at odds with structured level and world design. MineCraft, Terraria, and similar are great games that arguably have strong exploration elements, but not of the type this group promotes. 

Also, although the group welcomes easy games with practically no challenging elements, it's not for what some would call "non-games" that contain no gameplay at all (not that there's anything wrong with that).

The best exploration games not only let you explore interesting places, but also let you uncover secrets and gradually gain a better understanding of the mystical world around you.

Yes, yes, this is exactly the types of games I love too!

Are you among the niche that are thinking that? If you are, follow the Exploration Games curated group on Steam!

If you know some great games on Steam in this genre, let me know in the comments. And if you like, get in contact with me about becoming a member of the curated group who can add new recommendations to it.
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The Cluster

Sep 13, 2014 in , ,
The game I'm working on has a new name: The Cluster

Screenshot with title.
This replaces the previous working title "EaS". The full final name is likely going to be something along the lines of "Explorers of The Cluster", "Adventurers of The Cluster", "Enigmas of The Cluster" or similar, but I haven't decided on that yet. "The Cluster" is the defining part, and would be the recurring part if there should ever be more than one game in the series.

(For the sake of coherence I've retroactively updated past blog posts to use the new name.)

This post is about The Cluster, my 2.5D platform game under development with focus on non-linear exploration, set in a big, continuous world. You can read all the posts about The Cluster here.
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Debug your procedural world generation much easier with this one simple trick

This post is about The Cluster, my 2.5D platform game under development with focus on non-linear exploration, set in a big, continuous world. You can read all the posts about The Cluster here.

Okay cheesy title aside, this trick really did make debugging much easier for me, though the trick really is also very basic in retrospect. But it took me years to realize this, so maybe it will help somebody else too.

TLDR; freeze the generation at the exact point you encounter an error, but let the game continue running so you can inspect the frozen generation state with full visual context, turning various in-game debug visualizations on and off, and moving the camera around as needed.

A problem I've had for a long time is that errors in the procedural generation of my game can be hard to debug. The game have many sub-systems dependent on each other. When the player approaches an area that hasn't yet been generated, it will be generated by the various sub-systems on the fly with the various dependencies respected. Terrain info needs to be generated before path-finding info for instance.

The complexity of the dependency relations can make it hard to keep track of exactly how something went wrong, and whether an issue was caused by a bug in generation code itself, or a bug in the dependencies code that meant some needed information wasn't yet available.

Add to that the challenge that many of the generation algorithms modify data in several passes, and just looking at a visualization of the data at the end of the generation may not be sufficient to see how the data was wrong at some step in the middle of the process.

The normal way to inspect data in the middle of a process is by using breakpoints. But breakpoints only let you inspect data in your text/debugging IDE as numbers, and data for procedural generation is often incomprehensible at that low of an abstraction level. The custom-made visual debugging tools are really needed, but they can't be enabled and manipulated while the entire game is paused. And according to StackOverflow, individual threads can't be paused selectively.

Generation breakpoint triggered and visual debugging used to inspect the state.

For the trick to work, your procedural generation needs to fulfill these criteria
  • The generation should not happen on the main thread where the game loop and logic runs. This means you need to perform the procedural generation in one or more threads dedicated to that. This is pretty much needed anyway if your game generates new parts of the world on the fly without pausing the play. In my game I run all the generation in just one thread.
  • Make your life simpler by making it easy to switch various debug visualizations on and off at any point while running the game.
  • Obviously, have places in your code (such as asserts) where you check if what you take for granted is true and print a helpful error otherwise with as much info about the problem as possible. In addition to messages that are just printed in the console, I also have positional logging which shows up in the game world at a specific 3D position if the relevant debug visualization is enabled.
 The trick is to implement your own breakpoints that pause the generation thread. I did it like this:

Whereever I have detected a problem that I want to pause the game, I just call


In the Debugging class I have this code:

 static bool waitForBreakpoints = false;
 static bool breakpointPaused = false;
 public static void GenerationBreakpoint () {
  if (!waitForBreakpoints)
  breakpointPaused = true;
  while (breakpointPaused)
   System.Threading.Thread.Sleep (5);

I then have some debugging UI with a setting to turn waitForBreakpoints on and off, and a Resume button that is only shown when BreakpointPaused is true, and which sets it to false again when clicked.

That's it!
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