zendril

zendril

Hands-on Rust: spawn entities doesn't honor the frequency (page 276)

While converting to data driven spawning the data specifies that an item (like a dungeon map) has a frequency of 1.

However, when they actually get spawned, it is potentially creating many more of them (or none of them). This appears to be because it is leveraging map_builder.spawn_monsters which is hard coded to

const NUM_MONSTERS: usize = 50;

So that means this code is iterating over the 50 Points, rather than over the number of items in the available_entities:

        spawn_points.iter().for_each(|pt| {
            if let Some(entity) = rng.random_slice_entry(&available_entities) {
                self.spawn_entity(pt, entity, &mut commands);
            }
        });

Did I miss something, or is this indeed what is happening?

First Post!

herbert

herbert

Author of Hands-on Rust

Hi!

With hindsight, I should have used the rand crate’s weighted selection, but this seems to work. NUM_MONSTERS is meant to limit the total number of monsters - the actual weighting happens with available_entities.

At the top of spawn_entities (HandsOnRust/template.rs at main · thebracket/HandsOnRust · GitHub), available_entities is created by first filtering on level (so it only sees entities that can be on the level) and then inserting each entity a number of times equal to its frequency. So an orc with a frequency of 3 would be in available_entities 3 times.

So when random_slice_entry comes along and picks a slice entry, it includes all of the slice entries - including the duplicates. That preserves the weighting by template type.

Hope that makes sense?

Where Next?

Popular Pragmatic Bookshelf topics Top

ianwillie
Hello Brian, I have some problems with running the code in your book. I like the style of the book very much and I have learnt a lot as...
New
simonpeter
When I try the command to create a pair of migration files I get an error. user=> (create-migration "guestbook") Execution error (Ill...
New
mikecargal
Title: Hands-on Rust: question about get_component (page 295) (feel free to respond. “You dug you’re own hole… good luck”) I have somet...
New
swlaschin
The book has the same “Problem space/Solution space” diagram on page 18 as is on page 17. The correct Problem/Solution space diagrams ar...
New
leba0495
Hello! Thanks for the great book. I was attempting the Trie (chap 17) exercises and for number 4 the solution provided for the autocorre...
New
digitalbias
Title: Build a Weather Station with Elixir and Nerves: Problem connecting to Postgres with Grafana on (page 64) If you follow the defau...
New
creminology
Skimming ahead, much of the following is explained in Chapter 3, but new readers (like me!) will hit a roadblock in Chapter 2 with their ...
New
jwandekoken
Book: Programming Phoenix LiveView, page 142 (157/378), file lib/pento_web/live/product_live/form_component.ex, in the function below: d...
New
a.zampa
@mfazio23 I’m following the indications of the book and arriver ad chapter 10, but the app cannot be compiled due to an error in the Bas...
New
redconfetti
Docker-Machine became part of the Docker Toolbox, which was deprecated in 2020, long after Docker Desktop supported Docker Engine nativel...
New

Other popular topics Top

Devtalk
Hello Devtalk World! Please let us know a little about who you are and where you’re from :nerd_face:
New
AstonJ
If it’s a mechanical keyboard, which switches do you have? Would you recommend it? Why? What will your next keyboard be? Pics always w...
New
PragmaticBookshelf
Write Elixir tests that you can be proud of. Dive into Elixir’s test philosophy and gain mastery over the terminology and concepts that u...
New
Exadra37
I am thinking in building or buy a desktop computer for programing, both professionally and on my free time, and my choice of OS is Linux...
New
DevotionGeo
I know that -t flag is used along with -i flag for getting an interactive shell. But I cannot digest what the man page for docker run com...
New
AstonJ
Curious to know which languages and frameworks you’re all thinking about learning next :upside_down_face: Perhaps if there’s enough peop...
New
PragmaticBookshelf
Develop, deploy, and debug BEAM applications using BEAMOps: a new paradigm that focuses on scalability, fault tolerance, and owning each ...
New
CommunityNews
A Brief Review of the Minisforum V3 AMD Tablet. Update: I have created an awesome-minisforum-v3 GitHub repository to list information fo...
New
AnfaengerAlex
Hello, I’m a beginner in Android development and I’m facing an issue with my project setup. In my build.gradle.kts file, I have the foll...
New
AstonJ
Curious what kind of results others are getting, I think actually prefer the 7B model to the 32B model, not only is it faster but the qua...
New

Sub Categories: