Videos
- How do I get the platform starting point?
- How can I actually respawn the platform?
Started working on world 2, and one of the main mechanics of this world: quicksand. It won’t kill the player directly, but it will make it difficult for them to manoeuvre, and getting too low could cause death. Might be one of the more annoying mechanics in the game, but that’s kind of the point.
A bit more on Godot this evening, mainly working on pausing the game, and the end-of-level sequence. Have got something pretty close to what I was looking for: a very Mario-esc sequence where the player enters a castle, it start auto-walking the character, and the level stats show up and “spin” for a bit. Not too bad, although I may need to adjust the timing and camera a little to keep the stats from being unreadable.
Adventures In Godot: Respawning A Falling Platform
My taste of going through a Godot tutorial last week has got me wanting more, so I’ve set about building a game with it. Thanks to my limited art skills, I’m using the same asset pack that was used in the video, although I am planning to add a bit of my own here and there.
But it’s the new mechanics I enjoy working on, such as adding falling platforms. If you’ve played any platformer, you know what these look like: platforms that are suspended in air, until the player lands on them, at which point gravity takes a hold and they start falling, usually into a pit killing the player in the process:
The platforms are built as a CharacterBody2D with an Area2D that will detect when a player enters the collision shape. When they do, a script will run which will have the platform “slipping” for a second, before the gravity is turned on and the platform falls under it’s own weight. The whole thing is bundled as a reusable scene which I could drag into the level I’m working on.
I got the basics of this working reasonably quickly, yet today, I had a devil of a time going beyond that. The issue was that I wanted the platform to respawn after it fell off the map, so that the player wouldn’t get soft-locked at at an area where the platform was needed to escape. After a false-start trying to reposition the platform at it’s starting point after it fell, I figured it was just easier to respawn the platform when the old one was removed. To do this I had to solve two problems:
Getting The Starting Point
A Node2D object has the property global_position, which returns the position of the object based on the world coordinates. However, it seems like this position is not correct when the _init function of the attached script is called. I suspect this is because this function is called before the platform is added to the scene tree, when the final world coordinates are known.
Fortunately, there exists the _ready notification, which is invoked when the node is added to the scene tree. After some experimentation, I managed to confirm that global_position properly was correct. So tracking the starting point is a simple as storing that value in a variable:
var init_global_position = null
func _ready():
init_global_position = global_position
Another option is to use the _enter_tree() notification. From the documentation, it looks like either would probably work here, with the only difference being the order in which this notification is invoked on parents and children (_enter_tree is called by the parent first, whereas _ready is called by the children first).
Respawning The Platform
The next trick was finding out how to respawn the platform. The usual technique for doing so, based on the results of my web searching, is to load the platform scene, instantiate a new instance of it, and added it to the scene tree.
@onready var FallingPlatform = preload("res://scenes/falling_platform.tscn")
func respawn():
var dup = FallingPlatform.instantiate()
add_child(dup)
Many of the examples I’ve seen online added the new scene node as a child of the current node. This wouldn’t work for me as I wanted to free the current node at the same time, and doing so would free the newly instantiated child. The fix for this was easy enough: I just added the new node as a child of the current scene.
@onready var FallingPlatform = preload("res://scenes/falling_platform.tscn")
func respawn():
var dup = FallingPlatform.instantiate()
get_tree().current_scene.add_child(dup)
queue_free()
I still had to reposition the new node to the spawn point. Fortunately the global_position property is also settable, so it was simply a matter of setting that property before adding it to the tree (this is so that it’s correct when the newly instantiated node receives the _ready notification).
@onready var FallingPlatform = preload("res://scenes/falling_platform.tscn")
func respawn():
var dup = FallingPlatform.instantiate()
dup.global_position = init_global_position
get_tree().current_scene.add_child(dup)
queue_free()
This spawned the platform at the desired positioned, but there was a huge problem: when the player jumped on the newly spawn platform, it wouldn’t fall. The Area2D connection was not invoking the script to turn on the gravity:
It took me a while to figured out what was going on, but I came to the conclusion that the packed scene was loading properly, but without the script attached. Turns out a Script is a resource separate from the scene, and can be loaded and attached to an object via the set_script method:
@onready var FallingPlatform = preload("res://scenes/falling_platform.tscn")
@onready var FallingPlatformScript = preload("res://scripts/falling_platform.gd")
func respawn():
var dup = FallingPlatform.instantiate()
dup.set_script(FallingPlatformScript)
dup.global_position = init_global_position
get_tree().current_scene.add_child(dup)
queue_free()
Finally, after figuring all this out, I was able to spawn a new falling platform, have it positioned at the starting position of the old platform, and react to the player standing on it.
The time it took to work this out is actually a little surprising. I was expecting others to run into the same problem I was facing, where they were trying to instantiate a scene only to have the scripts not do anything. Yet it took me 45 minutes of web searching through Stack Overflow and forum posts that didn’t solve my problem. It was only after a bit of experimentation and print-debugging on my own that I realised that I actually had to attached the script after instantiating the node.
To be fair, I will attribute some of this to not understanding the problem at first: I actually thought the Area2D wasn’t actually being instantiated at all. Yet not one of the Stack Overflow answers or forum post floated the possibility that the script wasn’t being loaded alongside the scene. This does suggest to me that my approach may not be optimal. There does exist a “Local to Scene” switch in the script inspector that could help, although turning it on doesn’t seem to do much. But surely there must be some way to instantiate the script alongside the scene.
Anyway, that’s for later. For now, I’m happy that I’ve got something that works.
It lives!
Prototyped a game I had in mind, sort of a 2D Sokoban-like thing, where you control a robot with a retractable pushing arm that is to push gems to a “receiver” tile. Not entirely sure if it’s fun enough to actually build.
Used PixiJS to build it. Not a bad framework.
So sorry to hear about the loss of @merlinmann's pet lizard, which I just learnt is a central bearded dragon (they're good looking lizards). I didn't include it in the clip but he had some really nice things to say about it.
Request for any open-source projects that want to put banner ads on their site: please consider hard-coding the height of your banner to prevent the ad from reflowing the page. Otherwise, it may have an impact on the experience of those reading your docs.
Oh, that’s nice. Looks like Obsidian allows you to set the starting ordinal for numbered lists.
This was something I wish vanilla Markdown had for a while, so it’s good to see at least one Markdown editor embracing this.
Just heard the name for John's new app. Must say I kinda like it. It grows on you. No spoilers (except in the clip), but I do appreciate that it follows a similar vein to the crazy names I came up with. It just does it so much better.
More fun today working on Blogging Tools. Finished a feature for uploading larger videos to object storage so they can be added to a post using the standard video tag, as opposed to an embedded video player. If you see the screencast below, that means it’s working.
That’s it! I’m never going to use a framework that uses Webpack or installs more than 5 Node dev dependencies. Why? Because every time I check it out to work on it, all these dependencies break, and I’m left to spend hours updating them.
Never again! 😡
I wonder if we could convince Ben to order another run of Stratechery mugs shaped like the one he drinks from. I really like my Stratechery mug — it's one I often use — yet the mug he describes here is intriguing.
In other building-small-things-for-myself news, I spent a bit of time this morning on the image processor for Blogging Tools. The big new change was adding support for working with multiple source images, instead of just one. This made way for a new “Phone Shot” processor, which arranges multiple screenshots of phone apps in a row, while also downscaling them and proving some quick crops and distribution options.
This should reduce the vertical size of mobile app screenshots I post here, something that’s been bothering me a little.
Agree with @manton here. I used to be quite religious about Test Driven Development, but I'm less so nowadays. For the simple stuff, it works great; but for anything larger, you know little about how your going to build something until after you build it. Only then should you lock it in with tests.
Listening to this part of HV got me wondering if the secret to punctual trains is just a whole lot of them. You’re less likely to do something to delay a train — like hold the doors open — if you know the next one’s only a few minutes away, and will arrive on time. One builds on the other.
Just to add one point of anecdata to Ben’s experience: I’ve never been happy with the performance of the mobile radio of Pixel phones. You can be in the middle of the CBD and still experience weird dropouts while using mobile data. It’s quite frustrating.
While on my walk, I stopped briefly to clear a stone from my shoe and this purple swamphen (or pūkeko for our Kiwi friends) came up quite close to me. Not sure why. Looking for food maybe?
My recent exploration of Fyne has got me looking at building a level editor again. Have started work on the viewport, with camera movement using the WASD keys, and a basic mouse tracker for painting cells. Feels pretty good so far, although the cell mouse tracker might need some refinement.
Spending some time with the birds. Archie’s on heat, which is why she’s making those chirping noises. Ivy’s happily keeping to herself off to the side.
Day Trip to Bundanoon
Decided to go on a day trip to Bundanoon today. It’s been five years since I last visited and I remember liking the town enough that I thought it’d be worth visiting again. It’s not close, around 1 hour and 40 minutes from Canberra, but it not far either and I thought it would be a nice way to spend the day. Naturally, others agreed, which I guess explains why it was busier than I expected, what with the long weekend and all. Fortunately, it wasn’t too crowded, and I still had a wonderful time.
The goal was to go on a bush-walk first. I chose to do the Erith Coal Mine track, for no particular reason other than it sounded interesting. This circuit track was meant to take you to a waterfall by an old coal mine. However, the track leading to the actual mine was closed, thanks to the recent rain. In fact, if I could describe the bush-walks in one word, it would be “wet”. The ground was soaked, as were the paths, and although conditions were lovely, the paths were still very slippery.
After completing that circuit in probably 45 minutes, my appetite for bush-walking was still unsatisfied, so I tried the Fairy Bower Falls walk next. This was not as steep as the first one, but it turned to be a much harder track due to how wet and slippery everything was.
I stopped short of the end of this one too, as it seems the path was washed away. But I did manage to get a glimpse of the waterfall, so I’m considering that a win.
After that, I returned to the town for lunch and some train spotting. The train line to Goulburn runs through Bundanoon, and the last time I was there, there was probably a freight train every hour or so. So I was hoping to get a good view of a lot of freight traffic. Maybe shoot a video of a train passing through the station I could share here.
I had lunch outside and walked around the town a little, always within sight of the railway line, hoping for at least one train to pass through. But luck wasn’t on my side, and it wasn’t until I was on my way home that I saw what I think was a grain train passing through Wingello. I pulled over to take a video, and while I miss the locomotive, I got a reasonable enough recording of the wagons.
Being a little more hopeful, I stopped at Tallong, the next town along the road. I bought a coffee and went to the station to drink it and hopefully see a train pass through. Sadly, it was not to be. So I decided to head back home.
So the train spotting was a bust, and the bush-walks were difficult, but all in all it was quite a nice day. I look forward to my next visit to Bundanoon. Lets hope the trains are running a little more frequently then.