Implement object drafting

Relates to #23.

crates/objects/Cargo.toml

@@ -14,6 +14,7 @@ de_map = { path = "../map", version = "0.1.0-dev" }
 bevy = "0.7.0"
 iyes_loopless = "0.5.1"
 iyes_progress = { version = "0.3.0", features = [ "iyes_loopless" ] }
+glam = "^0.20.2"
 parry2d = { git = "https://github.com/Indy2222/parry", branch = "feature/dilation" }
 parry3d = "0.9.0"
 enum-map = "2.3.0"

crates/objects/src/draft.rs

@@ -0,0 +1,106 @@
+//! This module implements a Bevy plugin for drafting new objects on the map.
+//! This serves mostly as a visual guide for the user to correctly place new
+//! structures on the map.
+
+use std::f32::consts::TAU;
+
+use bevy::prelude::*;
+use de_core::{objects::ObjectType, projection::ToMsl, state::GameState};
+use glam::Vec2;
+use iyes_loopless::prelude::*;
+
+use crate::ObjectCache;
+
+pub(crate) struct DraftPlugin;
+
+impl Plugin for DraftPlugin {
+    fn build(&self, app: &mut App) {
+        app.add_event::<NewDraftEvent>()
+            .add_event::<MoveDraftEvent>()
+            .add_event::<RotateDraftEvent>()
+            .add_event::<ClearDraftsEvent>()
+            .add_system(new_draft.run_in_state(GameState::Playing));
+    }
+}
+
+/// Places a new draft on the map and removes all other drafts.
+pub struct NewDraftEvent {
+    object_type: ObjectType,
+    position: Vec2,
+}
+
+impl NewDraftEvent {
+    pub fn new(object_type: ObjectType, position: Vec2) -> Self {
+        Self {
+            object_type,
+            position,
+        }
+    }
+
+    fn object_type(&self) -> ObjectType {
+        self.object_type
+    }
+
+    fn position(&self) -> Vec2 {
+        self.position
+    }
+}
+
+pub struct MoveDraftEvent {
+    position: Vec2,
+}
+
+impl MoveDraftEvent {
+    pub fn new(position: Vec2) -> Self {
+        Self { position }
+    }
+}
+
+pub struct RotateDraftEvent {
+    angle: f32,
+}
+
+impl RotateDraftEvent {
+    /// # Panics
+    ///
+    /// Might panic if `angle` is not between zero (inclusive) and 2π
+    /// (exclusive).
+    pub fn new(angle: f32) -> Self {
+        debug_assert!(angle >= 0.);
+        debug_assert!(angle < TAU);
+        Self { angle }
+    }
+}
+
+pub struct ClearDraftsEvent;
+
+#[derive(Component)]
+struct Draft;
+
+fn new_draft(
+    mut commands: Commands,
+    drafts: Query<Entity, With<Draft>>,
+    cache: Res<ObjectCache>,
+    mut events: EventReader<NewDraftEvent>,
+) {
+    let event = match events.iter().last() {
+        Some(event) => event,
+        None => return,
+    };
+
+    for draft in drafts.iter() {
+        commands.entity(draft).despawn();
+    }
+
+    let transform = Transform {
+        translation: event.position().to_msl(),
+        ..Default::default()
+    };
+    let global_transform = GlobalTransform::from(transform);
+    let mut entity_commands = commands.spawn_bundle((global_transform, transform));
+    entity_commands.with_children(|parent| {
+        parent.spawn_scene(cache.get(event.object_type()).scene());
+    });
+}
+
+// TODO handle other events

crates/objects/src/lib.rs

@@ -5,12 +5,14 @@ use bevy::{app::PluginGroupBuilder, prelude::PluginGroup};
 use cache::CachePlugin;
 pub use cache::ObjectCache;
 pub use collider::{ColliderCache, ObjectCollider};
+use draft::DraftPlugin;
 pub use ichnography::{Ichnography, IchnographyCache};
 pub use spawner::SpawnEvent;
 use spawner::SpawnerPlugin;
 
 mod cache;
 mod collider;
+mod draft;
 mod ichnography;
 mod loader;
 mod spawner;
@@ -19,6 +21,6 @@ pub struct ObjectsPluginGroup;
 
 impl PluginGroup for ObjectsPluginGroup {
     fn build(&mut self, group: &mut PluginGroupBuilder) {
-        group.add(CachePlugin).add(SpawnerPlugin);
+        group.add(CachePlugin).add(SpawnerPlugin).add(DraftPlugin);
     }
 }