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use bevy::input::mouse::MouseMotion;
use bevy::prelude::*;
use bevy_render::camera::{Camera, PerspectiveProjection, VisibleEntities};
use bevy_render::render_graph::base;
pub struct FlyCameraOptions {
pub speed: f32,
pub sensitivity: f32,
pub pitch: f32,
pub yaw: f32,
}
impl Default for FlyCameraOptions {
fn default() -> Self {
Self {
speed: 10.0,
sensitivity: 3.0,
pitch: 0.0,
yaw: 0.0,
}
}
}
#[derive(Bundle)]
pub struct FlyCamera {
pub options: FlyCameraOptions,
pub camera: Camera,
pub perspective_projection: PerspectiveProjection,
pub visible_entities: VisibleEntities,
pub transform: Transform,
pub translation: Translation,
pub rotation: Rotation,
pub scale: Scale,
}
impl Default for FlyCamera {
fn default() -> Self {
Self {
options: FlyCameraOptions::default(),
camera: Camera {
name: Some(base::camera::CAMERA3D.to_string()),
..Default::default()
},
perspective_projection: Default::default(),
visible_entities: Default::default(),
transform: Default::default(),
translation: Default::default(),
rotation: Default::default(),
scale: Default::default(),
}
}
}
fn forward_vector(rotation: &Rotation) -> Vec3 {
rotation.mul_vec3(Vec3::unit_z()).normalize()
}
fn forward_walk_vector(rotation: &Rotation) -> Vec3 {
let f = forward_vector(rotation);
let f_flattened = Vec3::new(f.x(), 0.0, f.z()).normalize();
f_flattened
}
fn strafe_vector(rotation: &Rotation) -> Vec3 {
Rotation::from_rotation_y(90.0f32.to_radians())
.mul_vec3(forward_walk_vector(rotation))
.normalize()
}
fn movement_axis(
input: &Res<Input<KeyCode>>,
plus: KeyCode,
minus: KeyCode,
) -> f32 {
let mut axis = 0.0;
if input.pressed(plus) {
axis += 1.0;
}
if input.pressed(minus) {
axis -= 1.0;
}
axis
}
fn camera_movement_system(
time: Res<Time>,
keyboard_input: Res<Input<KeyCode>>,
mut query: Query<(&FlyCameraOptions, &mut Translation, &Rotation)>,
) {
let axis_h = movement_axis(&keyboard_input, KeyCode::D, KeyCode::A);
let axis_v = movement_axis(&keyboard_input, KeyCode::S, KeyCode::W);
let axis_float =
movement_axis(&keyboard_input, KeyCode::Space, KeyCode::LShift);
for (options, mut translation, rotation) in &mut query.iter() {
let delta_f = forward_walk_vector(rotation)
* axis_v
* options.speed
* time.delta_seconds;
let delta_strafe =
strafe_vector(rotation) * axis_h * options.speed * time.delta_seconds;
let delta_float =
Vec3::unit_y() * axis_float * options.speed * time.delta_seconds;
translation.0 += delta_f + delta_strafe + delta_float;
}
}
#[derive(Default)]
struct State {
mouse_motion_event_reader: EventReader<MouseMotion>,
}
fn mouse_motion_system(
time: Res<Time>,
mut state: ResMut<State>,
mouse_motion_events: Res<Events<MouseMotion>>,
mut query: Query<(&mut FlyCameraOptions, &mut Rotation)>,
) {
let mut delta: Vec2 = Vec2::zero();
for event in state.mouse_motion_event_reader.iter(&mouse_motion_events) {
delta += event.delta;
}
if delta == Vec2::zero() {
return;
}
for (mut options, mut rotation) in &mut query.iter() {
options.yaw -= delta.x() * options.sensitivity * time.delta_seconds;
options.pitch += delta.y() * options.sensitivity * time.delta_seconds;
if options.pitch > 89.9 {
options.pitch = 89.9;
}
if options.pitch < -89.9 {
options.pitch = -89.9;
}
let yaw_radians = options.yaw.to_radians();
let pitch_radians = options.pitch.to_radians();
rotation.0 = Quat::from_axis_angle(Vec3::unit_y(), yaw_radians)
* Quat::from_axis_angle(-Vec3::unit_x(), pitch_radians);
}
}
pub struct FlyCameraPlugin;
impl Plugin for FlyCameraPlugin {
fn build(&self, app: &mut AppBuilder) {
app
.init_resource::<State>()
.add_system(camera_movement_system.system())
.add_system(mouse_motion_system.system());
}
}