don't build over collidable/essential inner blocks

code/game/src/items.c

@@ -66,6 +66,10 @@ void item_use(ecs_world_t *ecs, ItemDrop *it, Position p, uint64_t udata) {
                     return;
                 }
             } 
+            // NOTE(zaklaus): This is an inner layer block, we can't build over it if it has a collision!
+            else if (l.block_id > 0 && blocks_get_flags(l.block_id) & (BLOCK_FLAG_COLLISION|BLOCK_FLAG_ESSENTIAL)) {
+                return;
+            } 
             world_chunk_replace_block(l.chunk_id, l.id, blocks_find(desc->place.kind + (asset_id)udata));
             it->quantity--;
         }break;

code/game/src/world/blocks.h

@@ -5,6 +5,7 @@
 typedef enum {
     BLOCK_FLAG_COLLISION = (1 << 1),
     BLOCK_FLAG_HAZARD = (1 << 2),
+    BLOCK_FLAG_ESSENTIAL = (1 << 3),
 } block_flags;
 
 int32_t blocks_setup(void);