From a804ceb430ad32ad536fe1091c725b9c1833cd9b Mon Sep 17 00:00:00 2001
From: Natalie <natalie@lilithuwu.com>
Date: Mon, 8 Jun 2026 17:51:48 -0700
Subject: [PATCH] =?UTF-8?q?fix(@projects/@magic-civilization):=20?=
 =?UTF-8?q?=F0=9F=90=9B=20fix=20axial-to-offset=20conversion=20for=20grid?=
 =?UTF-8?q?=20visibility?=
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Co-Authored-By: Lilith Autocommit <noreply@atlilith.com>
---
 .../engine/src/modules/ai/ai_turn_bridge.gd   | 20 +++++++--
 src/simulator/api-gdext/src/lib.rs            | 41 +++++++++++++++++++
 2 files changed, 57 insertions(+), 4 deletions(-)

diff --git a/src/game/engine/src/modules/ai/ai_turn_bridge.gd b/src/game/engine/src/modules/ai/ai_turn_bridge.gd
index 14db796f..820581c3 100644
--- a/src/game/engine/src/modules/ai/ai_turn_bridge.gd
+++ b/src/game/engine/src/modules/ai/ai_turn_bridge.gd
@@ -329,10 +329,18 @@ static func _refresh_learned_player_snapshot(gd_state: RefCounted) -> void:
 		for u: RefCounted in p.units:
 			if u == null or not u.is_alive():
 				continue
+			# CRITICAL (p1-29k root-cause fix): GDScript stores unit `position`
+			# in AXIAL (q, r), but the Rust grid + `compute_vision` +
+			# Move/Attack legal-action enumeration all operate in ODD-Q OFFSET
+			# (col, row) space (`neighbours_offset` parity-by-column +
+			# `wrap_coord` rectangular bounds). Passing raw axial put units
+			# off-grid → no tile under them → visible_tiles=0, move/attack=0.
+			# Convert to offset so units sit on the same grid the vision walk uses.
+			var u_off: Vector2i = HexUtilsScript.axial_to_offset(u.position)
 			unit_dicts.append({
 				"id": pi * ID_STRIDE + ui,
-				"col": int(u.position.x),
-				"row": int(u.position.y),
+				"col": u_off.x,
+				"row": u_off.y,
 				"hp": int(u.hp),
 				"max_hp": int(u.max_hp),
 				"attack": int(u.attack),
@@ -349,9 +357,13 @@ static func _refresh_learned_player_snapshot(gd_state: RefCounted) -> void:
 		for c: RefCounted in p.cities:
 			if c == null:
 				continue
+			# Same axial→offset conversion as units — city centres feed
+			# city-sourced vision (`compute_player_visible_set`) and the
+			# capital position, both in offset space.
+			var c_off: Vector2i = HexUtilsScript.axial_to_offset(c.position)
 			city_dicts.append({
-				"col": int(c.position.x),
-				"row": int(c.position.y),
+				"col": c_off.x,
+				"row": c_off.y,
 				"population": maxi(1, int(c.population)),
 				"food_yield": int(c.get("food_yield")) if c.get("food_yield") != null else 2,
 				"prod_yield": int(c.get("prod_yield")) if c.get("prod_yield") != null else 2,
diff --git a/src/simulator/api-gdext/src/lib.rs b/src/simulator/api-gdext/src/lib.rs
index bacea680..39b1cfee 100644
--- a/src/simulator/api-gdext/src/lib.rs
+++ b/src/simulator/api-gdext/src/lib.rs
@@ -4883,6 +4883,47 @@ impl GdGameState {
         d.set("attack_bits", attack_bits as i64);
         d.set("queue_production_bits", queue_production_bits as i64);
         d.set("trivial_bits", trivial_bits as i64);
+
+        // Grid introspection (hypothesis 1) — prove the grid is populated and
+        // that the player's first unit sits ON a real tile with a biome
+        // label. `tile_under_unit_biome` empty ⇒ the unit is off-grid
+        // (coordinate-space mismatch) — the exact failure mode behind
+        // visible_tiles=0.
+        match self.inner.grid.as_ref() {
+            Some(g) => {
+                d.set("grid_width", g.width as i64);
+                d.set("grid_height", g.height as i64);
+                d.set("grid_tiles", g.tiles.len() as i64);
+                let labelled = g
+                    .tiles
+                    .iter()
+                    .filter(|t| !t.biome_label_id.is_empty())
+                    .count();
+                d.set("grid_tiles_with_biome", labelled as i64);
+                if let Some(sample) = g.tiles.iter().find(|t| !t.biome_label_id.is_empty()) {
+                    d.set(
+                        "grid_sample_biome",
+                        GString::from(sample.biome_label_id.as_str()),
+                    );
+                }
+                // First own unit: report its (col,row) and the biome of the
+                // tile it occupies (empty string = no tile under it).
+                if let Some(ps) = self.inner.players.iter().find(|p| p.player_index == player) {
+                    if let Some(u0) = ps.units.first() {
+                        d.set("unit0_col", u0.col as i64);
+                        d.set("unit0_row", u0.row as i64);
+                        let biome_under = g
+                            .tile(u0.col, u0.row)
+                            .map(|t| t.biome_label_id.clone())
+                            .unwrap_or_default();
+                        d.set("tile_under_unit_biome", GString::from(biome_under.as_str()));
+                    }
+                }
+            }
+            None => {
+                d.set("grid_tiles", 0i64);
+            }
+        }
         d
     }