Attempted to leave type `PointerState` uninitialized

Question

I wanted to try to make a game in Rust using Piston. This is the first time I have used this library. I took this code from the official doc to test it. However, when my mouse touches the application window it closes immediately and I don’t understand why.

extern crate glutin_window;
extern crate graphics;
extern crate opengl_graphics;
extern crate piston;

use glutin_window::GlutinWindow as Window;
use opengl_graphics::{GlGraphics, OpenGL};
use piston::event_loop::{EventSettings, Events};
use piston::input::{RenderArgs, RenderEvent, UpdateArgs, UpdateEvent};
use piston::window::WindowSettings;

pub struct App {
    gl: GlGraphics, // OpenGL drawing backend.
    rotation: f64,  // Rotation for the square.
}

impl App {
    fn render(&mut self, args: &RenderArgs) {
        use graphics::*;

        const GREEN: [f32; 4] = [0.0, 1.0, 0.0, 1.0];
        const RED: [f32; 4] = [1.0, 0.0, 0.0, 1.0];

        let square = rectangle::square(0.0, 0.0, 50.0);
        let rotation = self.rotation;
        let (x, y) = (args.window_size[0] / 2.0, args.window_size[1] / 2.0);

        self.gl.draw(args.viewport(), |c, gl| {
            // Clear the screen.
            clear(GREEN, gl);

            let transform = c
                .transform
                .trans(x, y)
                .rot_rad(rotation)
                .trans(-25.0, -25.0);

            // Draw a box rotating around the middle of the screen.
            rectangle(RED, square, transform, gl);
        });
    }

    fn update(&mut self, args: &UpdateArgs) {
        // Rotate 2 radians per second.
        self.rotation += 2.0 * args.dt;
    }
}

fn main() {
    // Change this to OpenGL::V2_1 if not working.
    let opengl = OpenGL::V3_2;

    // Create an Glutin window.
    let mut window: Window = WindowSettings::new("spinning-square", [200, 200])
        .graphics_api(opengl)
        .exit_on_esc(true)
        .build()
        .unwrap();

    // Create a new game and run it.
    let mut app = App {
        gl: GlGraphics::new(opengl),
        rotation: 0.0,
    };

    let mut events = Events::new(EventSettings::new());
    while let Some(e) = events.next(&mut window) {
        if let Some(args) = e.render_args() {
            app.render(&args);
        }

        if let Some(args) = e.update_args() {
            app.update(&args);
        }
    }
}

The error:

thread 'main' panicked at 'attempted to leave type `platform::platform::x11::util::input::PointerState` uninitialized, which is invalid', /home/zenmoa/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/core/src/mem/mod.rs:658:9
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

score 5 · Accepted Answer · answered Dec 12 '20 at 03:47

This is apparently a bug in an old version of winit, which is fixed in the latest winit release. However, various crates e.g. amethyst, piston, ggez, etc. still use winit 0.19. In Rust 1.48.0 the issue has apparently manifested itself as a panic.

On the amethyst issue tracker a comment mentions, that for now a possible workaround is to revert back to Rust 1.47.0. If you're using rustup, then you can do that by executing the following command:

rustup default 1.47.0

Attempted to leave type `PointerState` uninitialized

1 Answers1