fennel_engine/
graphics.rs

1//! SDL3-backed graphics helper
2//!
3//! Provides:
4//! - `Graphics`: owned SDL context + drawing canvas
5//! - `Graphics::new(...)`: initialize SDL, create a centered resizable window and return [`Graphics`]
6//!
7
8use std::path::PathBuf;
9
10use sdl3::Sdl;
11use sdl3::pixels::PixelFormat;
12use sdl3::render::{Canvas, FRect};
13use sdl3::video::Window;
14
15use crate::resources::loadable::Image;
16use crate::resources::{self, LoadableResource, ResourceManager, loadable};
17
18/// Owned SDL variables used for rendering
19///
20/// - `canvas`: the drawing surface for the window
21/// - `sdl_context`: the SDL context
22pub struct Graphics {
23    /// The SDL3 canvas, required to draw
24    pub canvas: Canvas<Window>,
25    /// SDL3 contaxt
26    pub sdl_context: Sdl,
27    /// SDL3 texture creator
28    pub texture_creator: sdl3::render::TextureCreator<sdl3::video::WindowContext>,
29}
30
31impl Graphics {
32    /// Initialize SDL3, create a centered, resizable window and return a [`Graphics`]
33    /// container with the canvas and SDL context.
34    ///
35    /// # Parameters
36    /// - `name`: Window title.
37    /// - `dimensions`: (width, height) in pixels (u32).
38    ///
39    /// # Returns
40    /// - `Ok(Graphics)` on success.
41    /// - `Err(Box<dyn std::error::Error>)` on failure (window/canvas build error).
42    ///
43    /// # Example
44    /// ```ignore
45    /// let graphics = graphics::new(String::from("my cool game"), (500, 500))?;
46    /// ```
47    pub fn new(
48        name: String,
49        dimensions: (u32, u32),
50    ) -> Result<Graphics, Box<dyn std::error::Error>> {
51        // TODO: allow the user to uh customize video_subsystem configuration 'cuz man this is ass why
52        // do we position_centered() and resizable() it by default
53
54        let sdl_context = sdl3::init().unwrap();
55        let video_subsystem = sdl_context.video().unwrap(); // TODO: get this fucking unwrap out of
56        // here and replace with something more
57        // cool
58
59        let window = video_subsystem
60            .window(&name, dimensions.0, dimensions.1)
61            .position_centered()
62            .resizable()
63            .build()
64            .map_err(|e| e.to_string())?;
65
66        let canvas = window.into_canvas();
67        let texture_creator = canvas.texture_creator();
68        Ok(Graphics {
69            canvas,
70            sdl_context,
71            texture_creator,
72        })
73    }
74
75    /// Cache an image if it isn't cached and draw it on the canvas
76    ///
77    /// # Parameters
78    /// - `path`: Path to the image
79    /// - `position`: Where to draw the image in the window (x,y) in pixels (f32).
80    ///
81    /// # Returns
82    /// - `Ok(())` on success.
83    /// - `Err(Box<dyn std::error::Error>)` on failure
84    ///
85    /// # Example
86    /// ```ignore
87    /// graphics.draw_image(String::from("examples/example.png"), (0.0, 0.0));
88    /// ```
89    pub fn draw_image(
90        &mut self,
91        path: String,
92        position: (f32, f32),
93        manager: &mut ResourceManager,
94    ) -> anyhow::Result<()> {
95        if !manager.is_cached(path.clone()) {
96            // rust programmers when they have to .clone()
97            let texture = loadable::Image::load(PathBuf::from(path.clone()));
98            manager.cache_asset(texture?)?; // those question marks are funny hehehe
99        }
100
101        let image: &Image = resources::as_concrete(manager.get_asset(path).unwrap());
102        // .unwrap() in the line above should be safe
103        // because in the previous if block we
104        // make sure there is a texture with
105        // this key in cache
106        // otherwise i dunno :3
107        let surface = sdl3::surface::Surface::from_data(
108            image.as_mut_slice(),
109            image.width,
110            image.height,
111            image.width * 4,
112            PixelFormat::RGBA32,
113        )
114        .map_err(|e| e.to_string())
115        .unwrap();
116
117        let dst_rect = FRect::new(
118            position.0,
119            position.1,
120            surface.width() as f32,
121            surface.height() as f32,
122        );
123
124        let texture = self
125            .texture_creator
126            .create_texture_from_surface(surface)
127            .map_err(|e| e.to_string())
128            .unwrap();
129
130        self.canvas
131            .copy_ex(&texture, None, Some(dst_rect), 0.0, None, false, false)
132            .unwrap();
133
134        Ok(())
135    }
136}
fennel_engine/graphics.rs

fennel_engine/
graphics.rs
