Make stairs work

src/rpg/entity/entity.c

@@ -76,20 +76,43 @@ void entityWalk(entity_t *entity, const entitydir_t direction) {
   }
 
   // Get tile under foot
-  tile_t tile = mapGetTile(newPos);
-  if(tile == TILE_NULL && newPos.z > 0) {
-    // Check one level down for walkable tile (stairs down)
+  tile_t tileCurrent = mapGetTile(entity->position);
+  tile_t tileNew = mapGetTile(newPos);
+  bool_t fall = false;
+  bool_t raise = false;
+
+  // Are we walking up stairs?
+  if(
+    tileIsStairs(tileCurrent) &&
+    (direction+TILE_STAIRS_SOUTH) == tileCurrent &&
+    newPos.z < (MAP_CHUNK_DEPTH - 1)
+  ) {
+    tileNew = TILE_NULL;// Force check for stairs above.
+    worldpos_t abovePos = newPos;
+    abovePos.z += 1;
+    tile_t tileAbove = mapGetTile(abovePos);
+
+    if(tileAbove != TILE_NULL && tileIsWalkable(tileAbove)) {
+      // We can go up the stairs.
+      raise = true;
+    }
+  } else if(tileNew == TILE_NULL && newPos.z > 0) {
+    // Falling down?
     worldpos_t belowPos = newPos;
     belowPos.z -= 1;
-    tile_t belowTile = mapGetTile(belowPos);
-
-    if(belowTile == TILE_STAIRS_UP) {
-      tile = TILE_STAIRS_DOWN;// Mark current as stairs down
+    tile_t tileBelow = mapGetTile(belowPos);
+    if(
+      tileBelow != TILE_NULL &&
+      tileIsStairs(tileBelow) &&
+      (entityDirGetOpposite(direction)+TILE_STAIRS_SOUTH) == tileBelow
+    ) {
+      // We will fall to this tile.
+      fall = true;
     }
   }
 
-  // Tile walkable?
-  if(!tileIsWalkable(tile)) return;
+  // Can we walk here?
+  if(!raise && !fall && !tileIsWalkable(tileNew)) return;// Blocked
 
   // Entity in way?
   entity_t *other = ENTITIES;
@@ -105,13 +128,10 @@ void entityWalk(entity_t *entity, const entitydir_t direction) {
   entity->animation = ENTITY_ANIM_WALK;
   entity->animTime = ENTITY_ANIM_WALK_DURATION;// TODO: Running vs walking
 
-  // We are comitting, we can run effects here.
-  if(tile == TILE_STAIRS_DOWN) {
-    // Moving down a level
-    entity->position.z -= 1;
-  } else if(tile == TILE_STAIRS_UP) {
-    // Moving up a level
+  if(raise) {
     entity->position.z += 1;
+  } else if(fall) {
+    entity->position.z -= 1;
   }
 }