Files
another-asteroids/src/physics.rs

73 lines
2.1 KiB
Rust

//! Custom physics items
//! TODO: Refactor in terms of Rapier2D, *or* implement colliders and remove it.
use crate::WorldSize;
use bevy::prelude::*;
#[derive(Component)]
pub(crate) struct Position(pub(crate) bevy::math::Vec2);
#[derive(Component)]
pub(crate) struct Velocity(pub(crate) bevy::math::Vec2);
#[derive(Component)]
pub(crate) struct Rotation(pub(crate) f32);
/// Marker for any entity that should wrap on screen edges
#[derive(Component)]
pub(crate) struct Wrapping;
// TODO: Combine movement integration steps into one function
// They need to be ordered so the physics is deterministic. Bevy can enforce
// order, but it makes more sense to cut out the extra machinery and have one
// single function. Probably better for cache locality or whatever, too.
/*
Add velocity to position
*/
pub(crate) fn integrate_velocity(mut query: Query<(&mut Position, &Velocity)>, time: Res<Time>) {
for (mut position, velocity) in &mut query {
position.0 += velocity.0 * time.delta_secs();
}
}
pub(crate) fn update_positions(mut query: Query<(&mut Transform, &Position)>) {
for (mut transform, position) in &mut query {
transform.translation.x = position.0.x;
transform.translation.y = position.0.y;
}
}
/*
Assigns the rotation to the transform by copying it from the Rotation component.
*/
pub(crate) fn apply_rotation_to_mesh(mut query: Query<(&mut Transform, &Rotation)>) {
for (mut transform, rotation) in &mut query {
transform.rotation = Quat::from_rotation_z(rotation.0);
}
}
pub(crate) fn wrap_entities(
mut query: Query<&mut Position, With<Wrapping>>,
world_size: Res<WorldSize>,
) {
let right = world_size.width / 2.0;
let left = -right;
let top = world_size.height / 2.0;
let bottom = -top;
for mut pos in query.iter_mut() {
if pos.0.x > right {
pos.0.x = left;
} else if pos.0.x < left {
pos.0.x = right;
}
if pos.0.y > top {
pos.0.y = bottom;
} else if pos.0.y < bottom {
pos.0.y = top;
}
}
}