Splitting animation state from the texture in Tetra

anim_state.rs

use tetra::graphics::Rectangle;

#[derive(Debug, Clone)]
pub struct AnimationState {
    frames: Vec<Rectangle>,
    frame_length: i32,
    current_frame: usize,
    timer: i32,
}

impl AnimationState {
    pub fn new(frames: Vec<Rectangle>, frame_length: i32) -> AnimationState {
        AnimationState {
            frames,
            frame_length,
            current_frame: 0,
            timer: 0,
        }
    }

    pub fn tick(&mut self) {
        self.timer += 1;

        if self.timer >= self.frame_length {
            self.current_frame = (self.current_frame + 1) % self.frames.len();
            self.timer = 0;
        }
    }

    pub fn current_frame(&self) -> Rectangle {
        self.frames[self.current_frame]
    }
}

main.rs

mod anim_state;

use tetra::graphics::{self, Color, DrawParams, Rectangle, Texture};
use tetra::{Context, ContextBuilder, State};

use anim_state::AnimationState;

struct GameState {
    texture: Texture,
    animation: AnimationState,
}

impl GameState {
    fn new(ctx: &mut Context) -> tetra::Result<GameState> {
        Ok(GameState {
            texture: Texture::new(ctx, "./tiles.png")?,
            animation: AnimationState::new(
                Rectangle::row(0.0, 272.0, 16.0, 16.0).take(8).collect(),
                5,
            ),
        })
    }
}

impl State for GameState {
    fn update(&mut self, _ctx: &mut Context) -> tetra::Result {
        self.animation.tick();

        Ok(())
    }

    fn draw(&mut self, ctx: &mut Context, _dt: f64) -> tetra::Result {
        graphics::clear(ctx, Color::rgb(0.392, 0.584, 0.929));

        graphics::draw(
            ctx,
            &self.texture,
            DrawParams::new().clip(self.animation.current_frame()),
        );

        Ok(())
    }
}

fn main() -> tetra::Result {
    ContextBuilder::new("Hello, world!", 1280, 720)
        .build()?
        .run_with(GameState::new)
}