fennel_engine/resources/
mod.rs

1use std::{any::Any, cell::Ref, collections::HashMap, path::PathBuf};
2
3use crate::graphics::Graphics;
4
5/// Module containing implementations of [`LoadableResource`] such as [`Image`]
6pub mod loadable;
7
8/// Manages a collection of loadable resources indexed by their name
9pub struct ResourceManager {
10    /// Map resource name to a type that implements [`LoadableResource`] trait
11    pub resources: HashMap<String, Box<dyn LoadableResource>>,
12}
13
14/// Trait that all loadable assets must implement
15pub trait LoadableResource: Any {
16    /// Load a resource from `path` and return it boxed
17    ///
18    /// # Arguments
19    /// `path`: path to the resoruce file
20    /// `graphics`: current [`Graphics`] instance which holds `texture_creator` and `ttf_context`
21    /// `size`: optional size for any resoruce that needs it
22    ///
23    /// # Errors
24    /// Returns an error if the file cannot be read or parsed
25    fn load(
26        path: PathBuf,
27        graphics: &mut Graphics,
28        size: Option<f32>
29    ) -> anyhow::Result<Box<dyn LoadableResource>>
30    where
31        Self: Sized;
32
33    /// Eaasy-to-use identifier for the resource
34    fn name(&self) -> String;
35
36    /// Return a mutable slice that the graphics thread can pass to SDL
37    ///
38    /// If the resource does not have a buffer, then it mustn't implement this function
39    fn as_mut_slice(&self) -> Option<&mut [u8]> {
40        None
41    }
42
43    /// Return an immutable slice for read‑only access
44    ///
45    /// If the resource does not have a buffer, then it mustn't implement this function
46    fn as_slice(&self) -> Option<Ref<'_, [u8]>> {
47        None
48    }
49}
50
51/// evil &Box<dyn LoadableResource> to &T
52pub fn as_concrete<T: 'static + LoadableResource>(b: &Box<dyn LoadableResource>) -> anyhow::Result<&T> {
53    let dyn_ref: &dyn LoadableResource = b.as_ref();
54
55    let any_ref = dyn_ref as &dyn Any;
56
57    Ok(any_ref
58        .downcast_ref::<T>()
59        .expect("incorrect concrete type"))
60}
61
62impl ResourceManager {
63    /// Create a new manager with empty `resources` field
64    pub fn new() -> Self {
65        Self {
66            resources: HashMap::new(),
67        }
68    }
69
70    /// Insert a loaded asset into the cache
71    ///
72    /// The asset is stored under the key returned by `asset.name()`
73    pub fn cache_asset(&mut self, asset: Box<dyn LoadableResource>) -> anyhow::Result<()> {
74        self.resources.insert(asset.name(), asset);
75        Ok(())
76    }
77
78    // here i have NO fucking idea should it be `&Box<dyn LoadableResource>` or whatever
79    // self.resources.get returns a reference to the resource, so basically a reference to Box
80    // but afaik Box is a pointer, and for me it feels a bit fucking wrong to uh return a
81    // reference to a pointer >:3 and also clippy is angry at me for doing this
82    pub fn get_asset(&mut self, name: String) -> anyhow::Result<&Box<dyn LoadableResource>> {
83        let asset = self.resources.get(&name).unwrap();
84        Ok(asset)
85    }
86
87    /// Check if a resource is cached
88    pub fn is_cached(&mut self, name: String) -> bool {
89        self.resources.contains_key(&name)
90    }
91}
92
93impl Default for ResourceManager {
94    /// `default()` is equivalent to `ResourceManager::new()`.
95    fn default() -> Self {
96        Self::new()
97    }
98}
fennel_engine/resources/mod.rs

fennel_engine/resources/
mod.rs
