Allow 360° orbit, add Center View button and XYZ reference axes

Camera (apps/game/src/camera.rs):
- Replace yaw/pitch with a single Quat rotation. Mouse drag now does
  yaw-around-world-Y * rotation * pitch-around-local-X, which is gimbal-free
  and allows true 360° tumbling in any direction.
- Remove pitch clamps (ORBIT_MIN_PITCH / ORBIT_MAX_PITCH).
- Add ResetOrbitCamera resource + apply_orbit_reset system that snaps the
  orbit camera back to default on demand.
- OrbitCamera::reset() helper.

Galaxy scene (apps/game/src/gameplay/galaxy_creation/):
- New axes.rs: spawn_axes() draws three emissive cylinders through the
  origin (X=red, Y=green, Z=blue) as children of the scene root so they
  rebuild with the rest of the galaxy.
- UI adds a 'Center View' button below Regenerate that inserts
  ResetOrbitCamera; handled by reset_view_button_handler.
- Help text now mentions drag/zoom/escape.
This commit is contained in:
2026-06-04 13:08:47 -04:00
parent 1852cafcac
commit bc82f01ac1
4 changed files with 205 additions and 26 deletions

View File

@@ -9,24 +9,41 @@ pub struct MainCamera;
/// Orbit-style camera: rotates around `target` at `distance`, controlled by mouse.
/// Used for inspection scenes like GalaxyCreation where there is no player to follow.
///
/// Orientation is stored as a quaternion (`rotation`) to allow true 360° motion
/// with no gimbal lock. The base orientation is camera at `target + (0, 0, distance)`
/// looking toward `target` with up `+Y`. The quaternion rotates this base around
/// `target`. Mouse drag applies incremental rotations:
/// - horizontal delta → rotate around world `+Y` (yaw)
/// - vertical delta → rotate around the camera's local `+X` (its right vector)
///
/// This yaw-around-world / pitch-around-local split is the standard free-look
/// construction; it never produces a degenerate "up" vector at the poles.
#[derive(Component, Debug, Clone, Copy)]
pub struct OrbitCamera {
pub target: Vec3,
pub distance: f32,
/// Yaw around the Y axis (radians). 0 = camera at +Z looking toward origin.
pub yaw: f32,
/// Pitch above the horizontal plane (radians). 0 = horizontal, π/2 = straight down.
pub pitch: f32,
pub rotation: Quat,
}
impl OrbitCamera {
/// Reset to default orientation (camera at the canonical "starting" view).
pub fn reset(&mut self) {
*self = Self::default();
}
}
impl Default for OrbitCamera {
fn default() -> Self {
// ~36° above horizontal, slightly rotated, roughly matching the docs
// GalaxyScene opening shot. Built as yaw * pitch so the angles compose
// the same way the incremental drag rotations do.
let yaw = Quat::from_rotation_y(0.15);
let pitch = Quat::from_rotation_x(0.625);
Self {
target: Vec3::ZERO,
distance: 420.0,
yaw: 0.0,
// ~36° above horizontal — roughly matches docs GalaxyScene camera position.
pitch: 0.625,
rotation: yaw * pitch,
}
}
}
@@ -34,22 +51,25 @@ impl Default for OrbitCamera {
/// Initial camera spawn. The same entity is reused across states; control systems
/// decide how it moves depending on which state is active.
pub fn spawn_camera(mut commands: Commands) {
let orbit = OrbitCamera::default();
let offset = orbit.rotation * Vec3::new(0.0, 0.0, orbit.distance);
commands.spawn((
Camera3d::default(),
Transform::from_xyz(0.0, 260.0, 360.0).looking_at(Vec3::ZERO, Vec3::Y),
Transform::from_translation(orbit.target + offset)
.with_rotation(orbit.rotation)
.looking_at(orbit.target, Vec3::Y),
MainCamera,
OrbitCamera::default(),
orbit,
));
}
const ORBIT_ROTATE_SENSITIVITY: f32 = 0.005;
const ORBIT_ZOOM_SENSITIVITY: f32 = 0.1;
const ORBIT_MIN_PITCH: f32 = 0.15; // ~9° above horizontal — never fully edge-on
const ORBIT_MAX_PITCH: f32 = 1.4; // ~80° — never straight down (gimbal safeguard)
const ORBIT_MIN_DISTANCE: f32 = 40.0;
const ORBIT_MAX_DISTANCE: f32 = 1500.0;
/// Left-drag rotates around the orbit target; scroll wheel zooms.
/// No pitch clamping — the camera can tumble a full 360°.
///
/// Drag is suppressed when the cursor is over any UI node — otherwise clicking
/// buttons or panels would also rotate the camera.
@@ -76,11 +96,15 @@ pub fn orbit_camera_control(
if mouse_input.pressed(MouseButton::Left) && !cursor_over_ui {
for event in mouse_motion.read() {
orbit.yaw -= event.delta.x * ORBIT_ROTATE_SENSITIVITY;
// Vertical is flipped relative to a "trackball" feel so the content
// follows the finger (iPhone-style): drag down → camera rises →
// scene appears to shift down with the cursor.
orbit.pitch += event.delta.y * ORBIT_ROTATE_SENSITIVITY;
// iPhone-style: content follows the finger horizontally.
let yaw = Quat::from_rotation_y(-event.delta.x * ORBIT_ROTATE_SENSITIVITY);
// Vertical: drag down raises the camera so the scene appears to
// shift down with the cursor.
let pitch = Quat::from_rotation_x(event.delta.y * ORBIT_ROTATE_SENSITIVITY);
// Pre-multiply yaw (world-axis rotation), post-multiply pitch
// (local-axis rotation) — this preserves a stable horizon line as
// long as `rotation` doesn't already pitch past 90°.
orbit.rotation = yaw * orbit.rotation * pitch;
}
} else {
mouse_motion.clear();
@@ -91,15 +115,39 @@ pub fn orbit_camera_control(
orbit.distance *= 1.0 - event.y * ORBIT_ZOOM_SENSITIVITY;
}
orbit.pitch = orbit.pitch.clamp(ORBIT_MIN_PITCH, ORBIT_MAX_PITCH);
orbit.distance = orbit.distance.clamp(ORBIT_MIN_DISTANCE, ORBIT_MAX_DISTANCE);
let cos_p = orbit.pitch.cos();
let pos = orbit.target
+ Vec3::new(
orbit.distance * cos_p * orbit.yaw.sin(),
orbit.distance * orbit.pitch.sin(),
orbit.distance * cos_p * orbit.yaw.cos(),
);
*transform = Transform::from_translation(pos).looking_at(orbit.target, Vec3::Y);
// Position = target + rotation * (camera-forward * distance).
// In the base orientation the camera sits on +Z looking at the origin, so
// the offset is `rotation * +Z * distance`.
let offset = orbit.rotation * Vec3::new(0.0, 0.0, orbit.distance);
let position = orbit.target + offset;
*transform = Transform::from_translation(position)
.looking_at(orbit.target, Vec3::Y)
// Re-apply rotation to recover the roll component that `looking_at`
// would otherwise discard (matters when the camera is upside-down).
.with_rotation(orbit.rotation);
}
/// Resource: set by UI buttons (e.g. "Center View") to request the orbit camera
/// be reset to its default orientation on the next frame. Consumed by
/// [`apply_orbit_reset`].
#[derive(Resource, Default, Debug)]
pub struct ResetOrbitCamera;
/// If [`ResetOrbitCamera`] is present, snap the orbit camera back to default
/// and consume the resource. Lives in `Update` so UI button presses (which
/// insert the resource via `Commands`) take effect on the following frame.
pub fn apply_orbit_reset(
mut commands: Commands,
flag: Option<Res<ResetOrbitCamera>>,
mut query: Query<&mut OrbitCamera, With<MainCamera>>,
) {
let Some(_flag) = flag else { return };
let Ok(mut orbit) = query.single_mut() else {
commands.remove_resource::<ResetOrbitCamera>();
return;
};
orbit.reset();
commands.remove_resource::<ResetOrbitCamera>();
}