dialog WIP paths consolidation and rendering

src/systems/dialog_camera.rs

@@ -0,0 +1,74 @@
+use glam::Vec3;
+
+use crate::world::World;
+
+const CAMERA_LAG: f32 = 4.0;
+const VERTICAL_BIAS: f32 = 0.4;
+const MIN_DISTANCE: f32 = 8.0;
+const MAX_DISTANCE: f32 = 24.0;
+
+pub fn dialog_camera_system(world: &mut World, delta: f32)
+{
+    let Some((camera_entity, _)) = world.active_camera()
+    else
+    {
+        return;
+    };
+
+    let player_pos = world.player_position();
+
+    let character_positions: Vec<Vec3> = world
+        .bubble_tags
+        .all()
+        .iter()
+        .filter_map(|&bubble| {
+            let char_entity = world.dialog_bubbles.with(bubble, |b| b.character_entity)?;
+            world.transforms.with(char_entity, |t| t.position)
+        })
+        .collect();
+
+    if character_positions.is_empty()
+    {
+        return;
+    }
+
+    let all_positions: Vec<Vec3> = std::iter::once(player_pos)
+        .chain(character_positions.iter().copied())
+        .collect();
+
+    let centroid =
+        all_positions.iter().copied().fold(Vec3::ZERO, |a, b| a + b) / all_positions.len() as f32;
+
+    let max_spread = all_positions
+        .iter()
+        .map(|p| (*p - centroid).length())
+        .fold(0.0f32, f32::max);
+
+    let camera_distance = (max_spread * 1.8 + MIN_DISTANCE).min(MAX_DISTANCE);
+
+    let to_player = (player_pos - centroid).normalize_or(Vec3::Z);
+    let camera_back_dir = Vec3::new(to_player.x, 0.0, to_player.z).normalize_or(Vec3::Z);
+
+    let target_camera_pos =
+        centroid + camera_back_dir * camera_distance + Vec3::Y * camera_distance * VERTICAL_BIAS;
+
+    let current_camera_pos = world
+        .transforms
+        .with(camera_entity, |t| t.position)
+        .unwrap_or(target_camera_pos);
+
+    let smoothed = current_camera_pos.lerp(target_camera_pos, (CAMERA_LAG * delta).min(1.0));
+
+    world.transforms.with_mut(camera_entity, |t| {
+        t.position = smoothed;
+    });
+
+    let look_target = centroid + Vec3::Y * 1.0;
+
+    if let Some(camera) = world.cameras.get_mut(camera_entity)
+    {
+        let look_dir = (look_target - smoothed).normalize_or(-Vec3::Z);
+        camera.yaw = look_dir.z.atan2(look_dir.x);
+        camera.pitch = look_dir.y.asin();
+    }
+}