A Thread for Studying SRB2 Mapping

[ArcadeStriker]

First of all, I wasn't really sure about how to name this thread since the focus is a bit broad to word concisely (that and I'm not a native english speaker) so you could call the topic of this thread "Studying SRB2 maps in how they are made, what some of these do that can help basic to advanced SRB2 mappers in comprehension, tricks they use, layout and design analysis, and also great things that these maps do".

Now to not extend too far from this initial paragraph, I'm starting this with something I was writing last December as a document, but decided to put here as part of this topic, as it would be better for open discussion and contributions from others, as well as making my life easier in getting to add more myself. Also, remember that it always can be good to provide visual reference (screenshots from ZoneBuilder and ingame) when talking about a certain quirk from a level.

Studying the Skybox and Thok Barriers in Greenflower Zone Act 1

Despite that it is the starting point in the game’s default campaign, not only it gives a great first impression (specially thanks to the revamp it received in 2.2), but also already some nice techniques for the final visual result, and in this case we are going to inspect how GFZ1 managed to make a good looking skybox but also keeping the level boundaries closed with more detail.

The Skybox

An effective way to make a map feel livelier and more open, while at the same time actually saving resources (in other words, not having a real huge outside area outside the walls) is through skyboxes. While the F_SKY1 flat already is useful for a seamless sky effect when applied over sectors, skyboxes are useful as a way to make your own room that can act as the sky. This is the secret for how the sky in GFZ1 can have extra mountain decorations, as well as a water reflection AND a scrolling cloud texture at the ceiling.

Its hard to appreciate at most under the lower paths since you can only mostly see the sides and mountains, but in a higher area of the level, you can notice that there’s a lake effect right under the mountains; complete with a rippling effect. As mentioned before, there’s also a scrolling sky texture at the very top of the skybox. This results in having an interestingly elaborate but clean skybox, between the FOFs and scrolling clouds, and the fact that the mountains shown are actually linedef textures, as we will see in a second.

To begin understanding this one skybox, we need to refer to this closeup screenshot from the Zone Builder editor (in which a FOF’s control sector linedef is highlighted):

The reason why there’s a control sector linedef tagged to those is listed in the linedef’s action: It is a translucent water FOF that is tagged over there. This is clearer when inspecting the skybox itself with Zone Builder. However, there’s an interesting reveal when doing so; there are visible linedefs that don’t form any sectors in the screenshot above, as it turns out that these are used for extra mountain decorations. So, what is the catch here? The water FOF does not have anything to do with the mountain reflections (as water FOFs can’t do reflections).

The FOF itself having a ripple effect along with a cloudy texture and being translucent does a good job of simulating a nice reflecting water, but the mountain reflections on the water are actually textures with an upside-down copy right below it. If you haven't understood what this means, well…just take a look at how it appears without the water FOF being there:

So, in a nutshell, the skybox itself is comprised of a room with decorative mountain midtextures that, with that trick of mirroring the texture itself but passing it off as a reflection through the water FOF. The “orange walls” here are actually thok barriers; while they display like that here, ingame they just show the sky background texture that’s set to the map. On that note, the floor here is also set to F_SKY1, so you also end up having the sky effect below the translucent water. Interestingly, the scrolling ceiling texture is made through a linedef that is NOT in a control sector, but instead in one of the linedefs that’s right outside the skybox’s thok barrier. Since the linedef action used here determines the speed and direction of the scrolling by taking the linedef itself, this means that the length of this linedef and the way it goes is what determines the ceiling scrolling (which in this case isn’t really needed to be really specific).

Thok Barriers

The usage of thok barriers is essential in a way so that you can get outer walls/barriers/limits…that don’t simply appear as walls, but rather show the sky after a certain height while being impassable. Thok barriers are a middle point between a gap that shows the sky, and a wall that defines the limits of a map. In the picture below, while all the thok barriers are not highlighted, you can see that almost all of them that are selected in the screenshot below (in orange) are around the map itself.

A quick way to illustrate how thok barriers show up ingame, here’s a screenshot of one of the starting areas by default; the walls where you can see the sky above them are thok barriers, as while you can see the sky on top of them, you cannot walk or get in the sectors where these would be (like with Tails or Knuckles, for an example).

Now if we lower the thok barrier sector that is placed on here (which is used for the wall that goes from center to rightmost in the screenshot above) to a much lower floor level, we can see that instead of getting a big wall, we get a…clearer view of the skybox as there isn’t a raised wall/sector anymore, but still is an impassable area (can’t walk over that GFZFLR border).

The existence of skies and skyboxes is very effective for big sights with closed sector spaces when paired with thok barriers, as they will still display the sky effect while not taking real additional space. In any case, thok barriers were used accordingly to set boundaries on the map while looking as part of it.

EDIT: Also if you want to explore by yourself an "what-if" case if GFZ1 didn't use thok-barriers (and compare your experience there to the original map), you can check out this map which...gets rid of the thok barriers (though also did a lot like making caves and such use FOFs so that you can go over those as well; its a fascinating experiment).

I'm not an expert as mapping as some of the community members or Sonic Team Junior staff, but I always wanted to take a peek at what tricks the official maps pulled to give the maps their vibrant and solid visuals, as well as possibly attempting to explore about the layout design of the maps themselves. In any case, I don't know if I will be constant with posting in here but if I do come back here, you'll find more stuff like this from me ;)

 

[cookiefonster]

This was a really interesting read. I like seeing people go into detail analyzing what makes SRB2's levels good.

If you want to do more analysis of SRB2's levels, I suggest that outside of this thread you could help in beefing up the Level Design 101 pages on the SRB2 wiki to be up to 2.2 standards. The wiki still needs a lot of work to be updated to 2.2!

 

[ArcadeStriker]

Studying the potential of sectors and usage of FOFs with Greenflower Zone Act 2
Right now I haven't thought too much about what to talk about the level designs themselves gameplay-wise, so I thought on taking a look at GFZ2 and...realized that the STJr staff did not too many sectors but that end up giving a lot of depth and size to the map. You could call it something like "making more with less" or some sort of visual illusion since it does feel bigger than it should seem to be.

Simple in theory, complex in practice: Creating depth in an enviroment through sector and ceiling heights
Okay so try to take a look at the picture below, which is a snippet from GFZ2 open in Zone Builder. Notice the sector that's highlighted in orange (with the number 1 inside it); that's actually the sector where you spawn at the start of the level.

If you think that it is tough to picture a level from just this, then you'd be right. A bunch of shapes in a closed area like that making a vibrant hill with tall mountains?!? That's nonsense-

Well, its definitely tough to see it from a 2D plane than with a 3D reference, right? Now you may already have caught the similarity between these two pictures, but you definitely see the varying heights of terrain making everything blend together from...you know, other angles.

Now you can tell that the expansive feeling on this area was built solely out of clever sector decoration and heights, and while it wouldn't make nailing such a fantastic trick on first try easier, it certainly says volume about how creative the STJr staff was with the high mountain theme on this level. And another thing that needs to be stated that gives this area the high vertical feeling is...well, the outer walls and ceiling.

You probably noticed that the first picture had several holes inside the map outline; these are represented ingame as walls that reach up to ceiling height, but aren't sectors per se (if you wondered, you can delete enclosed sectors to make things like this). The ceiling height is also interestingly high, at a 4096 height which happens to be consistent through every outdoor section of this level.

Also, you can make some details with thok barriers to have the ceiling be high, but the visible wall be lower than the ceiling height (yet being impassable). One example is this part here where thok barriers were placed to make the highlighted linedefs (you can tell by their red tint from being selected) look like the top of the wall in that part; yet keeping the ceiling height at 4096. The second picture highlights the sector that is used for the thok barrier, with a value of 3584 floor and ceiling height (and having F_SKY1 as ceiling).

A highlight of using FOFs as natural decorative structures (and sector-sloped FOFs)

Now I'll try to be a bit more brief in this one: look at this. Don't these bridge-like shapes above the level look nice? You would have stumbled across this as well if you were roaming around the higher path (or just used Tails and Knuckles, which could easily get up places like this).

Sure, they do, but anyone that has dabbled with SRB2 mapmaking at this point should know that the only way to do this is through FOFs (floor-over-floor if you didn't know already) which are done by assigning the sector a tag (in this case it would be the grassy sectors that have the FOFs above), and the tag is assigned to a control linedef which basically says "hey buddy this is a solid opaque platform". The sector that has the linedef is called "control sector" and you pretty much make the floor height be the bottom height of the platform, and the ceiling height is the top height. About the tagging part, here you can see that there are several sectors tagged to a FOF control linedef, which is why there is a floating platform there. Also, the reason why it was correct to make an arch using FOFs instead of just lowering the ceilings is because...you wouldn't be able to see anything above the arch (nor go over it) if you tried to disguise some ceiling slopes with a F_SKY1 sector ceiling.

Now that's one thing, but what about the arch that is right above the tunnel entrance? That one looks sloped, and slopes are often done with a linedef that slopes the sector in front of it...but of course sector-based slopes on FOFs are possible. I highlighted the linedefs of the FOFs on the place where they are actually located (on the right, outside of the map boundaries), as well as the visible linedefs of the FOFs that show INSIDE the map, and the ground that was tagged to the FOF linedefs (look at the red grass/areas on the ground).

There is a set of sectors outside that have their floors and ceiling sloped, and these of course affect the displayed FOF inside the level. If you pay attention, you can tell that the size of the walls from the outside FOF sector and the product seen inside the map are the same, only that you see two different representations: The outside FOF is how the sectors are stored (with a set floor and ceiling height), while the result shown inside is what you should see as you tag the right sectors to these, showing the floor as the bottom of the platform, and the ceiling at the top.

However, for sector-based slopes to work, these control sectors must be aligned relative to the sectors that these will be tagged to. Here is a representation of how each linedef in these sectors are tagged to another sector inside the map, in which you should also notice how it lines up EXACTLY in one axis with the target sectors. This is important to do when working with sector-based slopes because any misalignment will pretty much botch any intended results.

While the explanation did seem a bit like a word salad, I might try to cover these and some other things as part of yet another thread but where instead of taking my time to dig into technical/design nuances of the official maps, I would try explaining how to make _______ in a map in a nutshell, as some short of bite-sized guides for specific things. And to cap this off, here's a simple screenshot of the tunnel itself, which is pretty much closed off in a 896 height ceiling; no FOFs for ceiling (because you can't go over it lol), no thok barriers, what you see here is what you get: a tunnel...were you expecting something else? ...wait no I'm not talking about water yet be patient please

 

[Othius]

Greenflower Zone has a lot of issues stemming from the fact that it's been run through many different mappers of different skill levels while still being an update of the same file used 20 years ago. Personally, out of all the stages in the game, I think it is in the most dire need of an overhaul. Especially because it is the first thing from vanilla people will reference when making their own maps, and by extention people copy the same mistakes.

As far as vanilla stages go, the best stages to look off of to see how they are built would be, for natural structures Deep Sea Act 1 and Arid Canyon Act 2. As far as architecture you'll undoubtedly want to look at Castle Eggman Act 2.

There are a few issues I'd like to address. The first one, for now, would have to be thok barriers.
If you were to ask me, thok barriers really server no purpose at all. The example you provided has a lot of negative side effects that can be solved by making more natural barriers and geometry.

First off, they block out the geometry behind it.

Ew!

Secondly, creates a really unnatural and artificial shape.

But how would these structures form naturally?
Simple, they have more depth to them than just a line around the stage. Instead, by giving them more shape and definition, and removing the thok barrier, you can have a shape that looks better and feels more like a real area.

I hate having my grid settings like this but it makes it easier to understand from a screenshot.

And it looks better in game too.

Here I turned it into some sort of mountain entrance.

I'll get into more details later. I'm a bit hard pressed for time so this is the most I can write for today.

 

[ArcadeStriker]

Greenflower Zone has a lot of issues stemming from the fact that it's been run through many different mappers of different skill levels while still being an update of the same file used 20 years ago. Personally, out of all the stages in the game, I think it is in the most dire need of an overhaul. Especially because it is the first thing from vanilla people will reference when making their own maps, and by extention people copy the same mistakes.

As far as vanilla stages go, the best stages to look off of to see how they are built would be, for natural structures Deep Sea Act 1 and Arid Canyon Act 2. As far as architecture you'll undoubtedly want to look at Castle Eggman Act 2.

There are a few issues I'd like to address. The first one, for now, would have to be thok barriers.
If you were to ask me, thok barriers really server no purpose at all. The example you provided has a lot of negative side effects that can be solved by making more natural barriers and geometry.

First off, they block out the geometry behind it.
View attachment 39389
Ew!

Secondly, creates a really unnatural and artificial shape.
View attachment 39390

But how would these structures form naturally?
Simple, they have more depth to them than just a line around the stage. Instead, by giving them more shape and definition, and removing the thok barrier, you can have a shape that looks better and feels more like a real area.
View attachment 39391
I hate having my grid settings like this but it makes it easier to understand from a screenshot.

And it looks better in game too.
View attachment 39392

Here I turned it into some sort of mountain entrance.

I'll get into more details later. I'm a bit hard pressed for time so this is the most I can write for today.

While right now I don't have much time/thoughts to write about from another map or anything, I'm really glad to see you post here; I can always trust that you will always have something quite insightful to comment from your amount of mapping experience

 

[Othius]

While right now I don't have much time/thoughts to write about from another map or anything, I'm really glad to see you post here; I can always trust that you will always have something quite insightful to comment from your amount of mapping experience

That's pretty flattering, thanks!

Figured I'd send the example wad itself too for anyone who cares.

 

[Mr Beagle]

Hi. I do believe this thread has the potential to be a lot more useful for mappers than both the wiki and the discord server (as the former doesn't get updated much and the latter sees everything buried after a day).

I will check regularly.

 

[clairebun]

Greenflower Zone has a lot of issues stemming from the fact that it's been run through many different mappers of different skill levels while still being an update of the same file used 20 years ago. Personally, out of all the stages in the game, I think it is in the most dire need of an overhaul. Especially because it is the first thing from vanilla people will reference when making their own maps, and by extention people copy the same mistakes.

In terms of scale and visuals I think GFZ is workable. However, the directioning is poor, especially in GFZ1's midsection, e.g. a new player can unwittingly circle themselves back to the last checkpoint if they try to explore the lake. My other major problem with GFZ comes from unsatisfying enemy behavior/variety, which is more of a systemic issue than an issue with level design.