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Refactor align example to use Dir3 random sampling (#13259)

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# Objective

Since `align` was introduced, it has been reworked to allow the input of
`Dir3` instead of `Vec3`, and we also introduced random sampling for
points on a sphere and then for `Dir3`. Previously, this example rolled
its own random generation, but it doesn't need to any more.

## Solution

Refactor the 'align' example to use `Dir3` instead of `Vec3`, using the
`bevy_math` API for random directions.
This commit is contained in:
Matty 2024-05-06 16:53:02 -04:00 committed by GitHub
parent 60a73fa60b
commit 6c78c7b434
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1 changed files with 5 additions and 22 deletions
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27
examples/transforms/align.rs
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@ -5,7 +5,6 @@ use bevy::input::mouse::{MouseButtonInput, MouseMotion};
use bevy::prelude::*;
use rand::{Rng, SeedableRng};
use rand_chacha::ChaCha8Rng;
use std::f32::consts::PI;
fn main() {
App::new()
@ -33,7 +32,7 @@ struct Cube {
}
#[derive(Component)]
struct RandomAxes(Vec3, Vec3);
struct RandomAxes(Dir3, Dir3);
#[derive(Component)]
struct Instructions;
@ -80,8 +79,8 @@ fn setup(
});
// Initialize random axes
let first = random_direction(&mut seeded_rng);
let second = random_direction(&mut seeded_rng);
let first = seeded_rng.gen();
let second = seeded_rng.gen();
commands.spawn(RandomAxes(first, second));
// Finally, our cube that is going to rotate
@ -185,8 +184,8 @@ fn handle_keypress(
if keyboard.just_pressed(KeyCode::KeyR) {
// Randomize the target axes
let first = random_direction(&mut seeded_rng.0);
let second = random_direction(&mut seeded_rng.0);
let first = seeded_rng.0.gen();
let second = seeded_rng.0.gen();
*random_axes = RandomAxes(first, second);
// Stop the cube and set it up to transform from its present orientation to the new one
@ -243,22 +242,6 @@ fn arrow_ends(transform: &Transform, axis: Vec3, length: f32) -> (Vec3, Vec3) {
(transform.translation, transform.translation + local_vector)
}
fn random_direction(rng: &mut impl Rng) -> Vec3 {
let height = rng.gen::<f32>() * 2. - 1.;
let theta = rng.gen::<f32>() * 2. * PI;
build_direction(height, theta)
}
fn build_direction(height: f32, theta: f32) -> Vec3 {
let z = height;
let m = f32::acos(z).sin();
let x = theta.cos() * m;
let y = theta.sin() * m;
Vec3::new(x, y, z)
}
// This is where `Transform::align` is actually used!
// Note that the choice of `Vec3::X` and `Vec3::Y` here matches the use of those in `draw_cube_axes`.
fn random_axes_target_alignment(random_axes: &RandomAxes) -> Transform {