initial commit

src/world/Warp.lua

@@ -0,0 +1,111 @@
+-- Warp resolution.  A warp fires when:
+--   * the player finishes a step onto a warp cell whose collision tile is a
+--     door tile or warp tile (stairs, doors, mats, cave entrances), or
+--   * the player stands on a warp cell and tries to walk off the map edge
+--     (exit carpets at the bottom of interiors), or
+--   * the player stands on a warp cell and the "extra" check passes -- on
+--     arrival with the d-pad held, or on a blocked step (route-gate
+--     doorways, the Vermilion dock entrance, ...).
+-- This mirrors pokered's CheckWarpsNoCollision / CheckWarpsCollision /
+-- ExtraWarpCheck (home/overworld.asm).
+
+local Warp = {}
+
+-- Returns the warp entry to take when arriving at (cx,cy), or nil.
+function Warp.onArrive(map, cx, cy)
+  local w = map:warpAtCell(cx, cy)
+  if w and map:isWarpTileCell(cx, cy) then
+    return w
+  end
+  return nil
+end
+
+local function inList(list, v)
+  for _, x in ipairs(list) do
+    if x == v then return true end
+  end
+  return false
+end
+
+-- ExtraWarpCheck: may the player standing at (cx,cy) facing dir warp
+-- without a door/warp tile underfoot?  On the carpet maps/tilesets the
+-- tile in FRONT of the player must be a warp-carpet tile for the facing
+-- direction (IsWarpTileInFrontOfPlayer; SS_ANNE_BOW tests one hardcoded
+-- tile instead); everywhere else the player must face the map edge
+-- (IsPlayerFacingEdgeOfMap).  carpets = field.warpCarpets.
+function Warp.extraCheck(map, carpets, cx, cy, dir)
+  local Collision = require("src.world.Collision")
+  local facingEdge =
+    (dir == "up" and cy == 0)
+    or (dir == "down" and cy == map.heightCells - 1)
+    or (dir == "left" and cx == 0)
+    or (dir == "right" and cx == map.widthCells - 1)
+  if not carpets then return facingEdge end
+  -- the map exceptions are tested before the tileset (ExtraWarpCheck)
+  local useCarpet
+  if inList(carpets.edgeMaps, map.id) then
+    useCarpet = false
+  elseif inList(carpets.function2Maps, map.id) then
+    useCarpet = true
+  else
+    useCarpet = inList(carpets.function2Tilesets, map.def.tileset)
+  end
+  if not useCarpet then return facingEdge end
+  local tx, ty = Collision.target(cx, cy, dir)
+  local front = map:cellTile(tx, ty)
+  if map.id == carpets.ssAnneBow.map then
+    return front == carpets.ssAnneBow.tile
+  end
+  return inList(carpets.tiles[dir], front)
+end
+
+-- Returns the warp entry when standing on (cx,cy) and the extra check
+-- passes toward dir (fired from a blocked step, or on arrival with the
+-- d-pad held).
+function Warp.onCollision(map, carpets, cx, cy, dir)
+  local w = map:warpAtCell(cx, cy)
+  if w and Warp.extraCheck(map, carpets, cx, cy, dir) then
+    return w
+  end
+  return nil
+end
+
+-- Returns the warp entry when standing on (cx,cy) and moving toward dir
+-- takes the player out of bounds.
+function Warp.onEdge(map, cx, cy, dir)
+  local w = map:warpAtCell(cx, cy)
+  if not w then return nil end
+  local Collision = require("src.world.Collision")
+  local tx, ty = Collision.target(cx, cy, dir)
+  if not map:inBounds(tx, ty) then
+    return w
+  end
+  return nil
+end
+
+-- Resolve a warp's destination to map id + cell.  LAST_MAP destinations
+-- (returning from an interior) resolve against the remembered outdoor
+-- map; the landing cell is that map's warp entry named by the warp id
+-- (wDestinationWarpID placement -- two-sided route gates land you on
+-- the side you exit, not where you entered).
+function Warp.destination(data, warpDef, lastMap)
+  local destMap = warpDef.destMap
+  if destMap == "LAST_MAP" then
+    assert(lastMap, "LAST_MAP warp with no remembered outdoor map")
+    destMap = lastMap.id
+    local destDef = data.maps[destMap]
+    local dw = destDef and destDef.warps[warpDef.destWarp]
+    if dw then
+      return destMap, dw.x, dw.y
+    end
+    -- out-of-range data: fall back to where the player entered
+    return destMap, lastMap.x, lastMap.y
+  end
+  local destDef = data.maps[destMap]
+  assert(destDef, "warp to unknown map " .. tostring(destMap))
+  local dw = destDef.warps[warpDef.destWarp]
+  assert(dw, ("warp to %s#%d out of range"):format(destMap, warpDef.destWarp))
+  return destMap, dw.x, dw.y
+end
+
+return Warp