Render mobs as * in viewport

Phase 3: look command now collects alive mob positions using the same
wrapping-aware relative position calc as players, and renders them as *
with the same priority as other players (after @ but before effects).

src/mudlib/commands/look.py

@@ -4,6 +4,7 @@ from typing import Any
 
 from mudlib.commands import CommandDefinition, register
 from mudlib.effects import get_effects_at
+from mudlib.mobs import mobs
 from mudlib.player import Player, players
 from mudlib.render.ansi import RESET, colorize_terrain
 
@@ -53,8 +54,30 @@ async def cmd_look(player: Player, args: str) -> None:
         if 0 <= rel_x < VIEWPORT_WIDTH and 0 <= rel_y < VIEWPORT_HEIGHT:
             other_player_positions.append((rel_x, rel_y))
 
+    # Build a list of (relative_x, relative_y) for alive mobs
+    mob_positions = []
+    for mob in mobs:
+        if not mob.alive:
+            continue
+
+        dx = mob.x - player.x
+        dy = mob.y - player.y
+        if dx > world.width // 2:
+            dx -= world.width
+        elif dx < -(world.width // 2):
+            dx += world.width
+        if dy > world.height // 2:
+            dy -= world.height
+        elif dy < -(world.height // 2):
+            dy += world.height
+        rel_x = dx + center_x
+        rel_y = dy + center_y
+
+        if 0 <= rel_x < VIEWPORT_WIDTH and 0 <= rel_y < VIEWPORT_HEIGHT:
+            mob_positions.append((rel_x, rel_y))
+
     # Build the output with ANSI coloring
-    # priority: player @ > other players * > effects > terrain
+    # priority: player @ > other players * > mobs * > effects > terrain
     half_width = VIEWPORT_WIDTH // 2
     half_height = VIEWPORT_HEIGHT // 2
 
@@ -68,6 +91,9 @@ async def cmd_look(player: Player, args: str) -> None:
             # Check if this is another player's position
             elif (x, y) in other_player_positions:
                 line.append(colorize_terrain("*", player.color_depth))
+            # Check if this is a mob's position
+            elif (x, y) in mob_positions:
+                line.append(colorize_terrain("*", player.color_depth))
             else:
                 # Check for active effects at this world position
                 world_x, world_y = world.wrap(

tests/test_mobs.py

@@ -301,3 +301,108 @@ class TestTargetResolution:
         assert player.mode == "combat"
         # Mob has no mode_stack attribute
         assert not hasattr(mob, "mode_stack")
+
+
+# --- Phase 3: viewport rendering tests ---
+
+
+class TestViewportRendering:
+    @pytest.fixture
+    def look_world(self):
+        """A mock world that returns a flat viewport of '.' tiles."""
+        from mudlib.commands.look import VIEWPORT_HEIGHT, VIEWPORT_WIDTH
+
+        w = MagicMock()
+        w.width = 256
+        w.height = 256
+        w.get_viewport = MagicMock(
+            return_value=[
+                ["." for _ in range(VIEWPORT_WIDTH)]
+                for _ in range(VIEWPORT_HEIGHT)
+            ]
+        )
+        w.wrap = lambda x, y: (x % 256, y % 256)
+        w.is_passable = MagicMock(return_value=True)
+        return w
+
+    @pytest.mark.asyncio
+    async def test_mob_renders_as_star(
+        self, player, goblin_toml, look_world
+    ):
+        """Mob within viewport renders as * in look output."""
+        import mudlib.commands.look as look_mod
+
+        old = look_mod.world
+        look_mod.world = look_world
+
+        template = load_mob_template(goblin_toml)
+        # Place mob 2 tiles to the right of the player
+        spawn_mob(template, 2, 0)
+
+        await look_mod.cmd_look(player, "")
+
+        output = "".join(
+            call[0][0] for call in player.writer.write.call_args_list
+        )
+        # The center is at (10, 5), mob at relative (12, 5)
+        # Output should contain a * character
+        assert "*" in output
+
+        look_mod.world = old
+
+    @pytest.mark.asyncio
+    async def test_mob_outside_viewport_not_rendered(
+        self, player, goblin_toml, look_world
+    ):
+        """Mob outside viewport bounds is not rendered."""
+        import mudlib.commands.look as look_mod
+
+        old = look_mod.world
+        look_mod.world = look_world
+
+        template = load_mob_template(goblin_toml)
+        # Place mob far away
+        spawn_mob(template, 100, 100)
+
+        await look_mod.cmd_look(player, "")
+
+        output = "".join(
+            call[0][0] for call in player.writer.write.call_args_list
+        )
+        # Should only have @ (player) and . (terrain), no *
+        stripped = output.replace("\033[0m", "").replace("\r\n", "")
+        # Remove ANSI codes for terrain colors
+        import re
+
+        stripped = re.sub(r"\033\[[0-9;]*m", "", stripped)
+        assert "*" not in stripped
+
+        look_mod.world = old
+
+    @pytest.mark.asyncio
+    async def test_dead_mob_not_rendered(
+        self, player, goblin_toml, look_world
+    ):
+        """Dead mob (alive=False) not rendered in viewport."""
+        import mudlib.commands.look as look_mod
+
+        old = look_mod.world
+        look_mod.world = look_world
+
+        template = load_mob_template(goblin_toml)
+        mob = spawn_mob(template, 2, 0)
+        mob.alive = False
+
+        await look_mod.cmd_look(player, "")
+
+        output = "".join(
+            call[0][0] for call in player.writer.write.call_args_list
+        )
+        import re
+
+        stripped = re.sub(r"\033\[[0-9;]*m", "", output).replace(
+            "\r\n", ""
+        )
+        assert "*" not in stripped
+
+        look_mod.world = old