From 60309f84a0b61fd7720054dc8baa3949505db858 Mon Sep 17 00:00:00 2001
From: hut <hut@hut.pm>
Date: Tue, 7 May 2024 22:04:47 +0200
Subject: [PATCH] update mapcam.center fast enough to avoid flicker on moving
 target

---
 src/camera.rs | 34 +++++++++++++++++++++++++++-------
 1 file changed, 27 insertions(+), 7 deletions(-)

diff --git a/src/camera.rs b/src/camera.rs
index 14f710d..d658bdc 100644
--- a/src/camera.rs
+++ b/src/camera.rs
@@ -40,6 +40,9 @@ impl Plugin for CameraPlugin {
             .after(PhysicsSet::Sync)
             .after(apply_input_to_player)
             .before(TransformSystem::TransformPropagate));
+        app.add_systems(PostUpdate, update_mapcam_center
+            .before(sync::position_to_transform)
+            .in_set(sync::SyncSet::PositionToTransform));
         app.add_systems(Update, update_map_camera);
         app.add_systems(Update, update_fov);
         app.add_systems(PreUpdate, apply_input_to_player);
@@ -74,6 +77,7 @@ pub struct MapCam {
     pub offset_x: f64,
     pub offset_z: f64,
     pub center: DVec3,
+    pub center_on_entity: Option<Entity>,
 }
 impl Default for MapCam {
     fn default() -> Self {
@@ -86,6 +90,7 @@ impl Default for MapCam {
             offset_x: 0.0,
             offset_z: 0.0,
             center: DVec3::new(0.0, 0.0, 0.0),
+            center_on_entity: None,
         }
     }
 }
@@ -161,8 +166,8 @@ pub fn update_map_camera(
     settings: Res<var::Settings>,
     mut mapcam: ResMut<MapCam>,
     mut q_camera: Query<&mut Transform, (With<Camera>, Without<actor::PlayerCamera>)>,
-    q_playercam: Query<(&Transform, &Position), (With<actor::PlayerCamera>, Without<Camera>)>,
-    q_target: Query<(&Transform, &Position), (With<hud::IsTargeted>, Without<Camera>, Without<actor::PlayerCamera>)>,
+    q_playercam: Query<(Entity, &Transform, &Position), (With<actor::PlayerCamera>, Without<Camera>)>,
+    q_target: Query<(Entity, &Transform, &Position), (With<hud::IsTargeted>, Without<Camera>, Without<actor::PlayerCamera>)>,
     q_target_changed: Query<(), Changed<hud::IsTargeted>>,
     mut mouse_events: EventReader<MouseMotion>,
     mut er_mousewheel: EventReader<MouseWheel>,
@@ -172,12 +177,13 @@ pub fn update_map_camera(
         return;
     }
     let mut camera_transform = q_camera.get_single_mut().unwrap();
-    let (player_trans, player_pos) = q_playercam.get_single().unwrap();
-    let (target_trans, target_pos) = if let Ok(target) = q_target.get_single() {
+    let (player_entity, player_trans, player_pos) = q_playercam.get_single().unwrap();
+    let (target_entity, target_trans, target_pos) = if let Ok(target) = q_target.get_single() {
         target
     } else {
-        (player_trans, player_pos)
+        (player_entity, player_trans, player_pos)
     };
+    mapcam.center_on_entity = Some(target_entity);
 
     // Get mouse movement
     let mut mouse_delta = Vec2::ZERO;
@@ -242,7 +248,6 @@ pub fn update_map_camera(
 
     // Update point of view
     let pov_rotation = DQuat::from_euler(EulerRot::XYZ, 0.0, mapcam.yaw as f64, mapcam.pitch as f64);
-    let offset = DVec3::new(mapcam.offset_x, 0.0, mapcam.offset_z);
     let point_of_view = pov_rotation * (mapcam.zoom_level as f64 * DVec3::new(1.0, 0.0, 0.0));
 
     // Update movement offset
@@ -255,11 +260,26 @@ pub fn update_map_camera(
     mapcam.offset_z += 0.01 * (direction.z * mapcam.zoom_level);
 
     // Apply updates to camera
-    mapcam.center = **target_pos + offset;
     camera_transform.translation = point_of_view.as_vec3();
     camera_transform.look_at(Vec3::ZERO, Vec3::Y);
 }
 
+pub fn update_mapcam_center(
+    mut mapcam: ResMut<MapCam>,
+    settings: Res<var::Settings>,
+    q_pos: Query<&Position>,
+) {
+    if !settings.map_active {
+        return;
+    }
+    if let Some(entity) = mapcam.center_on_entity {
+        if let Ok(pos) = q_pos.get(entity) {
+            let offset = DVec3::new(mapcam.offset_x, 0.0, mapcam.offset_z);
+            mapcam.center = **pos + offset;
+        }
+    }
+}
+
 pub fn update_fov(
     q_player: Query<&actor::ExperiencesGForce, With<actor::Player>>,
     mouse_input: Res<ButtonInput<MouseButton>>,