From 8ee1226525de5835bc13388cf53f7649c5d03ddc Mon Sep 17 00:00:00 2001
From: Martin Indra <martin.indra@mgn.cz>
Date: Tue, 31 May 2022 15:40:45 +0200
Subject: [PATCH] Use de_pathing crate for path finding

Fixes #12.
---
 Cargo.lock                       |  1 +
 crates/game/Cargo.toml           |  1 +
 crates/game/src/game/command.rs  | 14 +++---
 crates/game/src/game/mod.rs      |  4 +-
 crates/game/src/game/movement.rs | 73 ++++++++++++++++++++++++--------
 5 files changed, 69 insertions(+), 24 deletions(-)

diff --git a/Cargo.lock b/Cargo.lock
index 50588c550..c5dc500ef 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -1589,6 +1589,7 @@ dependencies = [
  "de_core",
  "de_index",
  "de_map",
+ "de_pathing",
  "futures-lite",
  "glam",
  "iyes_loopless",
diff --git a/crates/game/Cargo.toml b/crates/game/Cargo.toml
index ef257ae2a..7a76ea07a 100644
--- a/crates/game/Cargo.toml
+++ b/crates/game/Cargo.toml
@@ -10,6 +10,7 @@ repository = "https://github.com/Indy2222/Digital-Extinction"
 de_core = { path = "../core", version = "0.1.0-dev" }
 de_map = { path = "../map", version = "0.1.0-dev" }
 de_index = { path = "../index", version = "0.1.0-dev" }
+de_pathing = { path = "../pathing", version = "0.1.0-dev" }
 
 # Other
 bevy = "0.7"
diff --git a/crates/game/src/game/command.rs b/crates/game/src/game/command.rs
index d802f484a..4a6822e30 100644
--- a/crates/game/src/game/command.rs
+++ b/crates/game/src/game/command.rs
@@ -1,8 +1,8 @@
 use bevy::{
     input::mouse::MouseButtonInput,
     prelude::{
-        App, Entity, EventReader, EventWriter, MouseButton, ParallelSystemDescriptorCoercion,
-        Plugin, Query, Res, SystemSet, With,
+        App, Entity, EventReader, EventWriter, GlobalTransform, MouseButton,
+        ParallelSystemDescriptorCoercion, Plugin, Query, Res, SystemSet, With,
     },
 };
 use de_core::{objects::MovableSolid, projection::ToFlat};
@@ -26,7 +26,7 @@ impl Plugin for CommandPlugin {
 fn mouse_click_handler(
     mut click_events: EventReader<MouseButtonInput>,
     mut send_entity_events: EventWriter<SendEntityEvent>,
-    selected: Query<Entity, (With<Selected>, With<MovableSolid>)>,
+    selected: Query<(Entity, &GlobalTransform), (With<Selected>, With<MovableSolid>)>,
     pointer: Res<Pointer>,
 ) {
     if !click_events.iter().any(|e| e.button == MouseButton::Right) {
@@ -38,7 +38,11 @@ fn mouse_click_handler(
         None => return,
     };
 
-    for entity in selected.iter() {
-        send_entity_events.send(SendEntityEvent::new(entity, target));
+    for (entity, transform) in selected.iter() {
+        send_entity_events.send(SendEntityEvent::new(
+            entity,
+            transform.translation.to_flat(),
+            target,
+        ));
     }
 }
diff --git a/crates/game/src/game/mod.rs b/crates/game/src/game/mod.rs
index f8eab68b5..057c536ef 100644
--- a/crates/game/src/game/mod.rs
+++ b/crates/game/src/game/mod.rs
@@ -4,6 +4,7 @@ use bevy::{
 };
 use de_core::{gconfig::GameConfig, player::Player, state::GameState};
 use de_index::IndexPlugin;
+use de_pathing::PathingPlugin;
 use iyes_loopless::prelude::*;
 
 use self::{
@@ -34,7 +35,8 @@ impl PluginGroup for GamePluginGroup {
             .add(CommandPlugin)
             .add(MovementPlugin)
             .add(SpawnerPlugin)
-            .add(IndexPlugin);
+            .add(IndexPlugin)
+            .add(PathingPlugin);
     }
 }
 
diff --git a/crates/game/src/game/movement.rs b/crates/game/src/game/movement.rs
index fc467c7f9..e163feb96 100644
--- a/crates/game/src/game/movement.rs
+++ b/crates/game/src/game/movement.rs
@@ -2,6 +2,7 @@ use std::f32::consts::{FRAC_2_PI, PI};
 
 use bevy::prelude::*;
 use de_core::projection::ToMsl;
+use de_pathing::{Path, PathFinder};
 use glam::Vec2;
 
 use super::Labels;
@@ -24,44 +25,84 @@ impl Plugin for MovementPlugin {
 
 pub struct SendEntityEvent {
     entity: Entity,
+    source: Vec2,
     target: Vec2,
 }
 
 impl SendEntityEvent {
-    pub fn new(entity: Entity, target: Vec2) -> Self {
-        Self { entity, target }
+    pub fn new(entity: Entity, source: Vec2, target: Vec2) -> Self {
+        Self {
+            entity,
+            source,
+            target,
+        }
     }
 }
 
 #[derive(Component)]
 struct Target {
-    position: Vec2,
+    remaining: Vec<Vec2>,
+}
+
+impl Target {
+    fn peek(&self) -> Vec2 {
+        *self.remaining.last().unwrap()
+    }
+
+    fn pop(&mut self) -> bool {
+        self.remaining.pop();
+        self.remaining.is_empty()
+    }
 }
 
-impl From<Vec2> for Target {
-    fn from(position: Vec2) -> Self {
-        Self { position }
+impl From<Path> for Target {
+    fn from(path: Path) -> Self {
+        Self {
+            remaining: Vec::from(path.waypoints()),
+        }
     }
 }
 
-fn process_events(mut commands: Commands, mut events: EventReader<SendEntityEvent>) {
+fn process_events(
+    mut commands: Commands,
+    mut events: EventReader<SendEntityEvent>,
+    finder: Option<Res<PathFinder>>,
+) {
+    let finder = match finder {
+        Some(finder) => finder,
+        None => return,
+    };
+
     for event in events.iter() {
-        commands
-            .entity(event.entity)
-            .insert(Target::from(event.target));
+        if let Some(path) = finder.find_path(event.source, event.target) {
+            commands.entity(event.entity).insert(Target::from(path));
+        }
     }
 }
 
+// TODO precess PathFinderUpdated events
+
 fn move_objects(
     mut commands: Commands,
-    mut objects: Query<(Entity, &Target, &mut Transform)>,
+    mut objects: Query<(Entity, &mut Target, &mut Transform)>,
     time: Res<Time>,
 ) {
     let time_delta = time.delta().as_secs_f32();
 
-    for (entity, target, mut transform) in objects.iter_mut() {
-        let target_3d = target.position.to_msl();
-        let object_to_target = target_3d - transform.translation;
+    for (entity, mut target, mut transform) in objects.iter_mut() {
+        let object_to_target = loop {
+            let target_3d = target.peek().to_msl();
+            let object_to_target = target_3d - transform.translation;
+
+            if object_to_target.length() < TARGET_ACCURACY {
+                if target.pop() {
+                    commands.entity(entity).remove::<Target>();
+                    break object_to_target;
+                }
+            } else {
+                break object_to_target;
+            }
+        };
 
         let forward = transform.forward();
         let angle = forward.angle_between(object_to_target);
@@ -83,9 +124,5 @@ fn move_objects(
         let delta_scalar = MAX_SPEED * time_delta;
         let delta_vec = (delta_scalar * forward).clamp_length_max(object_to_target.dot(forward));
         transform.translation += delta_vec;
-
-        if (transform.translation - target_3d).length() < TARGET_ACCURACY {
-            commands.entity(entity).remove::<Target>();
-        }
     }
 }