One of the hallmarks of our previous game Brigador is its fully destructible environments. With a few exceptions, every prop visible within the games levels can be smashed through or blown up and left as a pile of debris on the ground. Here's a Touro from our first game next to some buildings showing the before, during and after effects of a stomp (right click > open image in new tab to get a better look).


[Images from Brigador: Up-Armored Edition] How this system works in Brigador is each prop, depending on a few factors like its size and what hit it, has a couple of destruction states (or variants of the prop) that then, when damaged enough, leave a flat rubble texture on the ground tiles which the player can walk through as if it were a regular ground tile.
[GIF from Brigador: Up-Armored Edition] Were adding what were calling systemic building collapse to this existing system in Brigador Killers. Related to it is a tactic that we tutorialize in the first game: mouse-holing. As developers we give you the ability to make your own space through that game's environment and its up to you to make use of that space in whatever way you the player deem fit. For instance in Brigador its entirely possible to just destroy one chunk of a building prop with certain weapons and not really affect anything else connected to or around it. If youre accurate enough and shoot through a sturdy-enough prop with something like a railgun, youll carve out a neat line through it. Heres a before and after of a typical Zeus shot in Brigador going through a couple of building props.

[Images from Brigador: Up-Armored Edition] What you can see is a convenient, Touro-wide hole through which to stomp through as a result. Although it serves our gameplay purposes in this game, this would not really be the case in real life as can be evidenced by looking at footage of any collapsing building (volume warning ahead). [previewyoutube=AGUqcnhJbeg;full][/previewyoutube]Rubble scatters around, dust kicks up to say nothing about anything or anyone that happens to be by a collapsing building. The structure of the damaged building is also heavily compromised and the rest of it is liable to fall as a result. The previous approach is also not suitable for BK for three big reasons:

• The change in initial scale from vehicle -> infantry
• Variable zoom for the player, and
• Buildings are much tougher and bigger than before

So, why were adding systemic building collapse is because we've raised the floor on how difficult it is to knock down a single building chunk, we want to keep the landscape malleable to the player in a way that's still exciting and potentially hazardous.
[GIF from BKTEST04] Behind the scenes, what's going on in the above gif? Imagine if you will a building and around that building it has the potential to cause damage to its surroundings when it collapses.

For the purposes of this exercise, suppose that this collapsing building will do three rings worth of damage. Each ring is in this example one point of damage each and each ring overlaps. For those of you that speak game development no, we are not ray marching these rings because that would be highly inefficient for our purposes. [If we for some reason did want to do that, wed have to shoot out rays in every direction from the point of collapse and test for intersection with another entity and then test to check if we had already applied damage to said entity and then test against each distance value in ascending order until we find the range that entity sits in and you get the idea.] The central red ring we can imagine is the immediate point of collapse where the most damage will be done. Anything within the space of this ring will take three points of damage (or more accurately: 1 + 1 + 1 from all three rings). Entities in the second orange ring will take two points (or 1 + 1), and anything in the blue will take just one point of damage. Note that these values are just for example purposes in the engine we can set the values of these rings to be whatever we want.
With all that said, what does systemic building collapse look like in action? You might guess from the image above that its just another form of how explosive props (such as pipelines) already work in Brigador. However, instead of shooting part of a pipeline that will almost immediately cause a violent chain reaction and take out everything else along that length of pipe, a collapsed building might only take out that part of the structure depending on the relative HP of the building segment, its neighbors and the source of damage. What that means is well still be able to retain some of the plinking at one prop chunk like before in Brigador, but unlike Brigador when that single chunk falls it will damage the surrounding building props by its collapse. Further plinking at other now-damaged parts can result in a subsequent domino-like collapse. Let's demonstrate this in BK with the help of some HP bars on the buildings by carefully shooting at an individual prop using a Me Dois...
As we damage the segment, note the green HP bar and the discoloration on the building. Lets keep shooting...
As we reduce that prop's HP to zero, it collapses and the two building props on either side have had their HP reduced by its collapse.
What we're left with here is a collapsed structure that can still serve as cover, but its height is reduced. The neighbouring buildings have been damaged by the collapse and it will not require as much effort to take them down. In addition, we see the accompanying white rubble on the ground indicating that it is traversable to the player. One example of how we intend this behavior to manifest in BK is the player using a building as cover which, at the start of an encounter, is sturdy and can clearly take an exchange of cannon fire. However, if the fight drags on, and more and more rounds batter the building and fill it with holes, the AoE damage starts to add up and - before it's too late - the splash from just one more shot will be enough to set off a domino effect and completely take out the entire building complex. The player's cover is gone and, depending on how close a player or other ground units are to a collapsing building, the effect may even be lethal. To give you an idea, we can violently speed this process up with our newly-revised Gravesend Pinball blasting through a set of buildings.
Take note that though the pinball itself is wide, its nowhere near as wide as three building props worth even coming through at a slight angle. Those with keener eyes will also notice the delay on the last building to collapse in the gif, along with the damage caused to the very last building in the row courtesy of the reduced HP bar (also note that the data for each suite of buildings needs to be manually configured, so part of the reason youre seeing the same building over and over here is because the values need to be calibrated for each one). Theres still some work to be done on systemic building collapse because, ironically, you cant just touch one thing in game development without it affecting other things. Already for legibility purposes we realize we have to lower the height of the walkable rubble so the on-foot player character doesnt get lost
as well as regrade the color of the rubble so it appears traversable to the player.
Though these are issues we are confident we can deal with through playtesting.
That's all for now for systemic building collapse. Next month we'll show off some new assets from our latest internal build. Lastly, our first game is currently on sale until Monday October 3rd and we recently put up a short article about the inspirations behind that game. Enjoy. https://store.steampowered.com/app/274500/Brigador_UpArmored_Edition/