Category: MineCraft

Good Morning from my Robotics Lab! This is Shadow_8472, and today, I am taking a break from the regular content on my blog and doing a tutorial on this easy Cave Spider XP farm I’ve developed with a little help. More on that later. Let’s get started!

Minecraft has a small zoo’s worth of farmable mobs, but one of the most challenging is the Cave Spider. With its ability to climb any surface as if it were covered with ladders and its tiny hit box, able to slink through all but the most airtight of hastily built walls, these pests are native to abandoned mineshafts, and nowhere else. The only reason anyone might even consider a Cave Spider XP farm is because of how often multiple spawners can generate close to one another.

.
This tutorial assumes you’ve already found an abandoned mine shaft full of cave spider spawners. Once you have a bunch of spawners captured, write down or take screen shots of each spawner’s coordinates. Remember, mob spawners only activate if you are within 16 blocks, so the farthest apart two spawner blocks can be is 32. If you aren’t sure if two blocks are in range, use the Pythagorean Theorem generalized for three dimensions, √[(x1-x2)²+(y1-y2)²+(z1-z2)²].

If you are looking to develop more than two spawners, which is usually the case if you are going to go for cave spiders, you’ll want to actually graph their x and z coordinates to filter out the false hopes a purely Pythagorean approach can yield. I recommend using a Geometry program like GeoGebra. Draw a 16 block radius around each spawner’s point and look for overlap. Once again, this won’t give you any hard positive results, but it will give you a fairly good idea of what to expect and how big your spawners’ overlap area is so you can start designing your grinding room.

You’re mostly on your own for the next part, since there is a plethora of possible arrangements between spawners, collection systems, and collection points, but I can give a few general tips.
Spawners won’t spawn mobs if too many are within a 9x9x9 box of the spawner block, centered on the exact middle of the spawner block. For maximum efficiency, drop your spiders down four blocks, then at least another two and into a water collection system.

Cave Spiders’ alleged super powers end when they can’t stick to ceilings. We can exploit this by using Iron Bars, Glass Panes, or the like to make a little overhang they can’t climb past. (From here on, whenever I say, “Iron Bars,” just use the narrow block of your choice.) To keep them from climbing into a corner and building up, we can use flowing water at the top to push them off the wall.

Here’s a cross section of my personal collection system. Important notes include highest part of the floor (the system need not be perfectly symmetric) is 4+2 blocks below any spawner above it, There are no water source blocks in the collection area itself, and the final water flow ends on the Iron Bars. Build the middle of the trough similarly, digging down whenever you run out of water instead of adding sources. The pistons are for a gimmicky lighting system I only recommend for those brave enough to deal with lava lighting.

My main innovation for this tutorial was this part right here. By lining the top of the transportation tunnels with top slabs (Trapdoors/Iron Trapdoors should also work and look nice), we don’t have to dig out so far to get that little tip of water to push the cave spiders back; a source and single flowing water should do. Once you are in the tunnel, feel free to use water sources whenever you drop the floor.

When you get to a corner, drop the waterline again and add a source block. On the upper “water rim,” be sure to use an upper slab so the spiders don’t get stuck on a quarter of an exposed block. Just carry the inner corner around the turn, but be sure you don’t accidently turn your flowing water into two lines of source blocks.

Here’s a picture of a Cave Spider grinder design from SteelToad, a colleague of mine from the server I play on. The Spider input is two wide, so I like to put a two wide soul sand bubble elevator in line with it and pipe them directly to the kill chamber.

Back in the plumbing, the entrance of the elevator is only a block wide. Unfortunately, we’ll need to use a pressure plate or sign to contain the elevator water and rely on the spiders pushing against each other to move things along. While we’re at it, we can lose the bars by adding water streams from the sides to guide the cave spiders into where they belong.

A final note: If you plan on any serious AFK time, be sure to include an auto killer switch. When I built this in survival, I used pistons to change the direction the elevator sent the spiders. Other than that, add whatever you want in a Cave Spider farm. Just don’t get too close to the spiders when whacking at them, as they can still occasionally bite.

Final Question: What other design improvements would you add?

Good Morning from my Robotics Lab! This is Shadow_8472, and today, I am bringing you another part to the slowing saga of the boat race port. Let’s get started!

Well, I have all the features ready to hopefully impress anyone interested in seeing it. The two landmark objectives this week were getting the teleport commands just right, and getting the boats to spin as the level starts.

The spin was an interesting story. This project is sort of a semi-secret from the rest of the server, so when I need help, I ask how to get a related problem. In the case of the spinning boats entering the level, I asked about how to make a cow spin in a tornado. I adjusted the selector (more generally: stuff I understood) to ask about actually getting a cow [boat] to spin. I ended up coming up with and refining my own solution, which in turn was unsuitable for the spinning cow.

Overall, the project is as close to the original as it’s going to get, barring some changes to reduce unwanted behavior. From this point, I’m going to be introducing new elements, making the whole experience even better.

At this point, I just need to show it off for that blind reaction I mentioned last week. It may be a while, so I think I’m going to start another project next week. Besides, I could blog about half of all the little, uninteresting optimizations I keep doing, but I’d just get bogged down and things would forever get thinner.

This project has been good for me. I cannot recall all the lessons I’ve learned along the way, but one of the newer ones is a reminder not to stop looking for a solution just because you ask out for an answer.

Final Question: What lessons from long projects have you learned?

Good Morning, from my Robotics Lab! This is Shadow_8472, and today, I’m almost done with my port of 2Cubed’s boat race. Let’s get started!

This week felt like progress was made in spurts thanks to both jam and Grifter, the two people from my MineCraft server helping me. About all my major accomplishments this week are in part to their command proofreading. Early on, I was working on the code to start the level. The /tp command and its supporting code was challenging to get just right. I came up with the idea to use an identifier block no player could [normally] see and reference it from commands later and jam helped me get something working. I was able to tune it in from there.

Jam once again helped me understand how the scoreboard works so I could build a level select. Long story short, imagine a spreadsheet. You have objectives at the top and entities on the side. Each cell at the intersection has a score to edit. There are no “global” scores, as much as I’d like to think that would make it easier on the learning curve. Objectives are added without attachment to an entity, but scores in those objectives are. Once I had that, I could step on a pressure plate to set my next_level objective to some level and load it with the alcove pressure plates.

Then came a day or few where nothing much happened, but with MineCraft 1.13 almost out, I wanted a workable demo by its launch date. A friend showed interest in seeing my work so far, and part way through the week, I scheduled a viewing on Friday, but I didn’t make it.

The next major hurdle after the teleport was how to tell if there were any players in the arena outside their boat and outside the starting area. After tossing the old command to jam and back (without luck), I passed the problem to Grifter, and he was awesome. He isolated a targeting selector I needed, where I likely would have figured it out in another few hours.

My focus sort of drifted to the win condition. Sure, it took me a while, but I eventually realized I could do it with a single command. Getting that command was another topic. I did most of the work in assembling it, and jam got me a snippet that gave me a working theory. The commands were a bit stubborn, but after I got something almost working, another chat with jam and it’s working.

The most recent challenge was targeting “cheating” players. The old game used scoreboards for almost everything. Something about a cheater tag showed up if you stood up and you weren’t in the start area. I wrote a command, finished by Grifter after hours of me doing trial and error, that spammed the word “hi” at any “cheating” players in adventure mode. And that’s where I am now. The next step is to replace the /say command embedded within the /execute with a function command to clean up players who might be done with a level.

I guess I have been making more progress than I thought this week. Before those last two breakthroughs on Sunday evening, I was all ready to make a big speech on progress and how a lack of success doesn’t mean you aren’t making any. Thomas Edison comes to mind with his brute force work on the electric light bulb. Once you know something doesn’t work, you don’t try it anymore. My difference here is that I’m documenting my progress with personal messages.

Final Question: I’ve now doubled my original project estimation time. I don’t really care. I’m getting working results on a semi-regular basis, and I might just get my 1.13 deadline. Even if I don’t make that one, I’d still like to get it working before my server updates. Have you ever worked with multiple deadlines for the same project?

Good Morning from my Robotics Lab! This is Shadow_8472, and today, I am updating my progress on the boat race. Let’s get started.

The race still isn’t playable. I managed to get the levels loading correctly from the command block room, special effects and all. All I’m just waiting on the completed functions back from jam.

In the meantime, my vision of this project has expanded. I’m now calling it the “Modular Game Center.” Basically, someone will be able to come in, flip some switches and play one of a number of games. Let’s say I have the expanded boat race and a golf course packed in there as well. The hardest part was programming for that eventual possibility.

Other than that, I showed off my work for last week’s post to a lot of the people involved in making the original boat race as well as my server admins. There’s word of the server resetting soon, so I’m hoping it will be done by then.

Once again, team building is the lesson up for learning here. This is a non-paid position, so if I don’t hear back from jam within a few days, I’m going to start figuring out how to do the functions myself. It will likely take a bit longer, but I found a great tutorial on how to build the commands.

Final Question: It’s a lot harder to write about writing software than building hardware. I don’t have as much to say this time… MineCraft kept crashing… Have you dealt with the pre-releases?

Good Morning from my Robotics Lab! This is Shadow_8472 and today, I’m starting a new project in MineCraft. Let’s get started!

A couple years ago, the MineCraft server I sometimes play in, Titancraft, had a special mini-game built for it where a player gets into any one of three arenas and plays through a series of five courses and gets an award at the end. Any of the arenas would load the player’s next level, but that was about it from a technical aspect, as far as I’ve figured out. I want to port it to MineCraft 1.13. (As of this writing, the MineCraft is on 1.13 release 3, updated in the middle of this week).

First, I contacted one of the moderators, GrifterMage, and got his blessing on the project. Then, I started setting up a server as close as the target software as possible. I understand the server runs on Spigot, and that they had been making 1.13 pre-release snapshots… which I couldn’t seem to compile. I setup a vanilla server thinking this project is likely to take either two or three weeks.

I started looking into installing structure block files. They had changed for 1.13. Now, they are part of something with a steeper learning curve, but have all the more power once you get the idea of them: datapacks. Following the trend of going from texture packs to resource packs, datapacks are a new series of files that organize simple modifications to the game. All I know about them so far is that they contain both functions and structures, which before now were more free floating in their own folders, and that the packs themselves can be switched on and off.

With a vanilla server and a bit of ambition, I set about making a “Hello World” function. I asked for some help on the server’s Discord channel, and a user by the name of DrHenchman was helpful in pointing me to the correct way to structure a datapack; I sent him a bunch of screenshots as I debugged my way to victory.

Structure block files can save and load sections of the world up to 32 blocks in each of the three directions, so I made four test levels of 32×32 blocks and got them to load from a datapack on the server.

When I started thinking about the actual levels, I started looking for any videos someone may have had with footage of when the map was originally operational. I found acg1000’s posted livestream from when the custom dimension containing the boat race was opened, but two hours seemed a bit much for a just-adequate-for-YouTube WiFi connection when I needed to skip around a bit. After I skimmed it using my PC, low quality, and 2x speed. He didn’t have it…. Later, GrifterMage managed to scare up the original structure block files for me to work on. Another mod, DropDaBass, apparently had a copy. They are both awesome for that.

The files are two years old. A lot of things have changed since then. First of all, from 1.12 to 1.13, structure files no longer accept capital letters in their file names. Even though I was cautioned against it, I tried copying the files directly into 1.13 and changing the names and dropping them in the correct place to load them. I don’t remember exactly what happened, but they didn’t work correctly. I ended up having to load them all up in 1.12 and re-save them.

Which brought me to another challenge. One of the levels features floating water blocks. Before, they were simply “still_water”, a feature removed for 1.13. As a side effect, the now-regular water blocks flooded the level. As a step in the correct direction, I put a repeat command block out to continuously clean up the drips. The seizure alert results should have been expected. I then messed around with using “structure_void” blocks to hold up the water, since they look the same as air when you’re in adventure mode. Structure_void blocks are about the one block structure blocks cannot copy. So I set my commands to filling each level with them as soon as it was loaded. The next command replaced any leaked water blocks, in case of any lag Grifter pointed out there may be. Ultimately, I’m opting to just use a crazy block, like diamond ore blocks, to contain the water until they can be replaced when the level loads.

Around this time, I poked into loading the actual arena building, including the lobby and thee arena floors above it I gutted two of the three arena command blocks and started installing the hardware for my port. The existing logic no longer functioned, in either 1.12 or 1.13. After an hour or two, I found the credits to three people who originally worked on it. TheDukeMinecraft, listed as Project Manager, Designer, and Builder; 2CubedTech, listed as Tester and Command Writer; and dminer78 listed as Tester and Food Eater.

I reached out to the only original designer still present on Titancraft’s Discord server, Duke. He was eventually able to put me in contact with 2Cubed. Both seem excited that their old project is getting some love, but I got the impression both are busy with their own endeavors.

While I was waiting for messages back from Duke and later 2Cubed, work continued on the design. One of my priorities is minimizing load on the server. This means as few repeat command blocks running their contents every tick as possible. (Another reason why the blinking water was a bad idea). All I really need is two end conditions listening for if the player is standing or if his boat is at the goal, a line of three gold blocks. To make things more interesting, I wanted the ability to load one of two maps for each level, one classic or one newly built for the grand re-opening. While I still don’t have the logic figured out, I have a comment version of it in the server files. These are very likely to get rethought and scrapped.

I looked out in the vast, 30×30 room that was the command block room. It is so big! There’s room for a lot more than just a few levels. I mocked up some structure blocks and found that each arena can hold up to 4 separate games of 5 levels each, with 6 variants of each level. And then I did one better. After working with the levels themselves, I produced a version that loads both halves from a single structure block. Now that that 4×5 corridor can hold even more levels. Plenty of room for expansion.

This week, my lesson has been about building a team. My skills don’t quite encompass the full spectrum of tasks that need to be done. As I was starting my writeup, a fellow Titancraft member, jamcdonald120 just agreed to help with the scoreboard commands. As soon as I get the files transferred over to my server computer, I’m looking to have him help me with those.

Final Question: Did you know that, even though it will work and act all normal, MineCraft 1.13 pre-releases don’t seem to like dashes in their file names?