Mouse motion delta shows absolute position instead of position change

[Galedon]

Hi, I am trying to make some camera rotation based on mouse movement. But the mouse motion event reader does not seem to do what I expect.
Expectation: getting cursor position change during the frame
Reality: getting absolute position of the cursor, but only if its being moved

main.rs:

use bevy::prelude::*;
use bevy::input::mouse::{MouseMotion, };

fn main() {
    App::new()
        .add_plugins(DefaultPlugins)
        .add_systems(Update, (
            read_mouse_movement
        ))
        .run();
}
fn read_mouse_movement(
    mouse: Res<ButtonInput<MouseButton>>,
    mut motion_events: EventReader<MouseMotion>
){
    if mouse.pressed(MouseButton::Right){
        for motion in motion_events.read() {
            println!("{:?}", motion);
        }
    }
}

cargo.toml:

[package]
name = "untitled"
version = "0.1.0"
edition = "2024"

# Enable a small amount of optimization in the dev profile.
[profile.dev]
opt-level = 1

# Enable a large amount of optimization in the dev profile for dependencies.
[profile.dev.package."*"]
opt-level = 3

[dependencies]
bevy = { version = "0.16.0", features = ["dynamic_linking"] }

output:

MouseMotion { delta: Vec2(37011.0, 24333.0) }
MouseMotion { delta: Vec2(36670.0, 24859.0) }
MouseMotion { delta: Vec2(36579.0, 25101.0) }
MouseMotion { delta: Vec2(36579.0, 25546.0) }
MouseMotion { delta: Vec2(36602.0, 25870.0) }
MouseMotion { delta: Vec2(36761.0, 26315.0) }

What did I do wrong?

[Henauxg]

This seems to be a bug. Your snippet works fine on my machine:

MouseMotion { delta: Vec2(0.0, -1.0) }
MouseMotion { delta: Vec2(-1.0, -2.0) }
MouseMotion { delta: Vec2(0.0, -1.0) }
MouseMotion { delta: Vec2(0.0, -1.0) }
...

You could open an issue with your specific platform/OS/..

[Galedon]

Thank you for the reply. It pointed me to do some tests and I found out that the problem was that I was using the remote desktop. I will open the issue.

[tkhatibi]

I have the same problem with bevy-0.16 in wsl2:

• WGPU_BACKEND=vulkan
• WSLg is enabled

mouse position delta returns absolute position, while cursor moved delta returns position change