Fog of war: unexplored darkness until the dungeon's ground, creatures or towers come close

- explored tiles stay known (saved compactly as bits), enemies are only drawn while in sight; sight runs along open ground, walls block it
- unexplored tiles are black blocks; units, towers, torches, furniture, portals, gate and rival cores in the dark are hidden; minimap and tile info too
- the nearest portal is known from the start; the seer's eye opens a wide area for 20 seconds without remembering it

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

src/ui.rs

@@ -704,7 +704,9 @@ impl Ui {
             for (i, t) in g.map.t.iter().enumerate() {
                 let (x, y) = xy(i);
                 let mut c = minimap_color(t);
-                if t.marked {
+                if !g.map.shown(i) {
+                    c = [0, 0, 0, 255];
+                } else if t.marked {
                     c = [255, 230, 90, 255];
                 }
                 self.minimap_img.set_pixel(x as u32, y as u32, Color::from_rgba(c[0], c[1], c[2], c[3]));
@@ -717,7 +719,7 @@ impl Ui {
         draw_texture_ex(&self.minimap_tex, mrx, mry, WHITE, DrawTextureParams { dest_size: Some(vec2(map_w, map_h)), ..Default::default() });
         let dot = (2.0 * px).max(ms);
         for e in &g.ents {
-            if e.alive && !e.held {
+            if e.alive && !e.held && !crate::render3d::unit_hidden(g, e) {
                 let c = if e.hero {
                     Color::new(0.6, 0.85, 1.0, 1.0)
                 } else if e.dwarf() {
@@ -1146,6 +1148,10 @@ pub fn hover_info(g: &Game, ent: Option<usize>, tile: Option<(i32, i32)>) -> Vec
         return out;
     }
     let Some((x, y)) = tile else { return out };
+    if !g.map.shown(idx(x, y)) {
+        out.push((tr("tile.unexplored"), DIM));
+        return out;
+    }
     if let Some(tr) = g.trap_at(idx(x, y)) {
         use crate::traps::*;
         out.push((tr_name(tr.kind), FRAME_HI));