Fix laser beam blocked by own tile, consolidate enemy-type checks

Beam raycast now skips the tile the turret is mounted on, so
wall-embedded laser turrets can shoot outward.

Extract entity_is_enemy() into engine/entity.c as single source
of truth for enemy-type checks. Replaces triplicated type lists
in level.c, drone.c, and projectile.c that caused the collision
bug when new enemy types were added.

src/engine/entity.c

@@ -126,3 +126,17 @@ void entity_register(EntityManager *em, EntityType type,
     em->render_fn[type] = render;
     em->destroy_fn[type] = destroy;
 }
+
+bool entity_is_enemy(const Entity *e) {
+    switch (e->type) {
+        case ENT_ENEMY_GRUNT:
+        case ENT_ENEMY_FLYER:
+        case ENT_TURRET:
+        case ENT_ENEMY_CHARGER:
+        case ENT_SPAWNER:
+        case ENT_LASER_TURRET:
+            return true;
+        default:
+            return false;
+    }
+}

src/engine/entity.h

@@ -80,4 +80,8 @@ void entity_register(EntityManager *em, EntityType type,
                      EntityUpdateFn update, EntityRenderFn render,
                      EntityDestroyFn destroy);
 
+/* Returns true if the entity is a hostile enemy type.
+ * Single source of truth — add new enemy types here. */
+bool entity_is_enemy(const Entity *e);
+
 #endif /* JNR_ENTITY_H */

src/game/drone.c

@@ -34,9 +34,7 @@ static Entity *find_nearest_enemy(Vec2 from, float range) {
     for (int i = 0; i < s_em->count; i++) {
         Entity *e = &s_em->entities[i];
         if (!e->active || e->health <= 0) continue;
-        if (e->type != ENT_ENEMY_GRUNT && e->type != ENT_ENEMY_FLYER &&
+        if (!entity_is_enemy(e)) continue;
-            e->type != ENT_TURRET      && e->type != ENT_ENEMY_CHARGER &&
-            e->type != ENT_SPAWNER     && e->type != ENT_LASER_TURRET) continue;
         Vec2 epos = vec2(e->body.pos.x + e->body.size.x * 0.5f,
                          e->body.pos.y + e->body.size.y * 0.5f);
         float dx = epos.x - from.x;

src/game/laser_turret.c

@@ -38,12 +38,14 @@ static Entity *find_player(EntityManager *em) {
     return NULL;
 }
 
-/* Raycast from (ox, oy) along (dx, dy) in tile steps.
+/* Raycast from (ox, oy) along (dx, dy) in pixel steps.
  * Returns the world-space endpoint where the beam hits
- * a solid tile or the map boundary. Step size is one
+ * a solid tile or the map boundary. Ignores the turret's
- * pixel for accuracy. Max range prevents runaway. */
+ * own tile (skip_tx, skip_ty) so wall-mounted turrets can
+ * shoot outward. Max range prevents runaway. */
 static void beam_raycast(const Tilemap *map,
                          float ox, float oy, float dx, float dy,
+                         int skip_tx, int skip_ty,
                          float *out_x, float *out_y) {
     float max_range = 800.0f; /* pixels */
     float step = 1.0f;
@@ -58,6 +60,7 @@ static void beam_raycast(const Tilemap *map,
         int tx = (int)(x / TILE_SIZE);
         int ty = (int)(y / TILE_SIZE);
         if (tx < 0 || ty < 0 || tx >= map->width || ty >= map->height) break;
+        if (tx == skip_tx && ty == skip_ty) continue;
         if (tilemap_is_solid(map, tx, ty)) break;
     }
 
@@ -111,10 +114,13 @@ static void laser_turret_update(Entity *self, float dt, const Tilemap *map) {
     if (dx < 0) self->flags |= ENTITY_FACING_LEFT;
     else         self->flags &= ~ENTITY_FACING_LEFT;
 
-    /* Compute beam endpoint via raycast */
+    /* Compute beam endpoint via raycast (skip turret's own tile) */
     float dir_x = cosf(ld->aim_angle);
     float dir_y = sinf(ld->aim_angle);
-    beam_raycast(map, cx, cy, dir_x, dir_y, &ld->beam_end_x, &ld->beam_end_y);
+    int self_tx = (int)(cx / TILE_SIZE);
+    int self_ty = (int)(cy / TILE_SIZE);
+    beam_raycast(map, cx, cy, dir_x, dir_y, self_tx, self_ty,
+                 &ld->beam_end_x, &ld->beam_end_y);
 
     /* Damage cooldown */
     if (ld->damage_cd > 0) ld->damage_cd -= dt;

src/game/level.c

@@ -233,12 +233,6 @@ static void damage_player(Entity *player, int damage, Entity *source) {
     }
 }
 
-static bool is_enemy(const Entity *e) {
-    return e->type == ENT_ENEMY_GRUNT || e->type == ENT_ENEMY_FLYER ||
-           e->type == ENT_TURRET      || e->type == ENT_ENEMY_CHARGER ||
-           e->type == ENT_SPAWNER     || e->type == ENT_LASER_TURRET;
-}
-
 static void handle_collisions(EntityManager *em) {
     /* Find the player */
     Entity *player = NULL;
@@ -267,7 +261,7 @@ static void handle_collisions(EntityManager *em) {
                 bool hit = false;
 
                 /* Player bullet hits enemies */
-                if (from_player && is_enemy(b)) {
+                if (from_player && entity_is_enemy(b)) {
                     if (physics_overlap(&a->body, &b->body)) {
                         damage_entity(b, a->damage);
                         hit = true;
@@ -293,7 +287,7 @@ static void handle_collisions(EntityManager *em) {
 
         /* ── Enemy contact damage to player ──── */
         if (player && !(player->flags & ENTITY_INVINCIBLE) &&
-            is_enemy(a) && !(a->flags & ENTITY_DEAD)) {
+            entity_is_enemy(a) && !(a->flags & ENTITY_DEAD)) {
             if (physics_overlap(&a->body, &player->body)) {
                 /* Check if player is stomping (falling onto enemy from above) */
                 bool stomping = (player->body.vel.y > 0) &&

src/game/projectile.c

@@ -251,9 +251,7 @@ static void projectile_update(Entity *self, float dt, const Tilemap *map) {
 
             /* Player bullets target enemies, enemy bullets target player */
             if (is_player_proj) {
-                if (e->type != ENT_ENEMY_GRUNT && e->type != ENT_ENEMY_FLYER &&
+                if (!entity_is_enemy(e)) continue;
-                    e->type != ENT_TURRET      && e->type != ENT_ENEMY_CHARGER &&
-                    e->type != ENT_SPAWNER     && e->type != ENT_LASER_TURRET) continue;
             } else {
                 if (e->type != ENT_PLAYER) continue;
             }