Rust and Sdl2 crate, can't see sprite on window

[carlosri]

I'm following a tutorial to develope a game while learning rust. The problem is that can't see the sprite on the window, here is the code.

use sdl2::pixels::Color;
use sdl2::event::Event;
use sdl2::keyboard::Keycode;
use sdl2::render::{WindowCanvas, Texture};
use sdl2::rect::{Point, Rect};
use sdl2::image::{self, LoadTexture, InitFlag};
use std::time::Duration;

fn render(
    canvas: &mut WindowCanvas,

    color: Color,
    texture: &Texture,
    position: Point,
    sprite: Rect,
) -> Result<(), String> {
    canvas.set_draw_color(color);
    canvas.clear();

    let (width, height) = canvas.output_size()?;

   
    let screen_position = position + Point::new(width as i32 / 2, height as i32 / 2);
    let screen_rect = Rect::from_center(screen_position, sprite.width(), sprite.height());
    canvas.copy(texture, sprite, screen_rect)?;

    canvas.present();

    Ok(())
}

fn main() -> Result<(), String> {
    let sdl_context = sdl2::init()?;
    let video_subsystem = sdl_context.video()?;
    let _image_context = image::init(InitFlag::PNG | InitFlag::JPG)?;

    let window = video_subsystem.window("game tutorial", 800, 600)
        .position_centered()
        .build()
        .expect("could not initialize video subsystem");

    let mut canvas = window.into_canvas().build()
        .expect("could not make a canvas");

    let texture_creator = canvas.texture_creator();
    let texture = texture_creator.load_texture("../assets/bardo.png")?;

    let position = Point::new(0, 0);
    // src position in the spritesheet
    let sprite = Rect::new(0, 0, 26, 36);

    let mut event_pump = sdl_context.event_pump()?;
    let mut i = 0;
    'running: loop {
        // Handle events
        for event in event_pump.poll_iter() {
            match event {
                Event::Quit {..} |
                Event::KeyDown { keycode: Some(Keycode::Escape), .. } => {
                    break 'running;
                },
                _ => {}
            }
        }

        // Update
        i = (i + 1) % 255;

        // Render
        render(&mut canvas, Color::RGB(250, 64, 255), &texture, position, sprite)?;

        // Time management!
        ::std::thread::sleep(Duration::new(0, 1_000_000_000u32 / 60));
    }

    Ok(())
}

[zthompson47]

I was able to see the sprite when I ran your code. The only catch is that you have to run cargo r from within the src directory so that load_texture can find ../assets as a relative path.

Do you get an error message?

[carlosri]

Thanks for the answer.
I don't get any errors.
I get the window changing colors
yes, I'm runing cargo in the src folder

[zthompson47]

@carlosri

I get the window changing colors

I wonder if you're somehow running different code than you posted above. The code above does not change the window color. i is updated in your loop, but the value is not used to color the canvas. The tutorial uses it like so:

render(&mut canvas, Color::RGB(250, 64, 255 - i), &texture, position, sprite)?;

You might also double check your copy of the bardo.png spritesheet (open in image editor) to make sure you have the correct image in your project.