new options, and hot keys and readme clean up

src/battle/BattleState.lua

@@ -30,6 +30,9 @@ local TypeChart = require("src.battle.TypeChart")
 local BattleState = {}
 BattleState.__index = BattleState
 BattleState.isOpaque = true
+-- Letterbox voids around the 160x144 battle canvas fill white so the
+-- window reads as one continuous battle screen (no black bars).
+BattleState.letterboxWhite = true
 
 -- Battle colors itself per-pixel (species pics + HP bar tints), so the
 -- SGB whole-screen remap must not run over it.

src/core/Game.lua

@@ -246,7 +246,11 @@ end
 function Game:zoomStep(delta)
   local Zoom = require("src.render.Zoom")
   if not Zoom.gateOK(self.stack:top(), self.overworld) then return end
-  Zoom.step(delta, Renderer:fitScale())
+  local offset = Zoom.step(delta, Renderer:fitScale())
+  if self.save and self.save.options then
+    self.save.options.zoom = offset
+    self:writeOptions()
+  end
 end
 
 function Game:wheelmoved(_, dy)
@@ -320,6 +324,14 @@ function Game:keypressed(key)
       self:writeOptions()
     end
     return
+  elseif key == "4" then
+    -- cycle ZOOM through every integer level (survey → FIT → close-up → wrap)
+    local Zoom = require("src.render.Zoom")
+    if Zoom.gateOK(self.stack:top(), self.overworld) then
+      self.save.options.zoom = Zoom.cycle(Renderer:fitScale())
+      self:writeOptions()
+    end
+    return
   elseif key == "5" then
     -- cycle GBC FX OFF → 1 → 2 → 3 → 4 (unlit-GBC ladder); always on
     -- desktop.  Mobile refuses the present shader (issue #136).
@@ -445,6 +457,8 @@ function Game:applyOptions(opts)
   if Sound.applyOptions then Sound.applyOptions(opts) end
   require("src.render.PaletteFX").applyOptions(opts)
   require("src.render.Tilt").applyOptions(opts)
+  require("src.render.Zoom").applyOptions(opts)
+  require("src.render.TileRenderer").applyOptions(opts)
   -- returns true when a persisted GBC FX level was cleared on mobile
   local gbcCleared = require("src.render.GBCFX").applyOptions(opts)
   require("src.core.VideoMode").applyOptions(opts)

src/core/SaveData.lua

@@ -186,10 +186,14 @@ function SaveData.defaultOptions()
     musicFilter = 0,
     -- logic fast-forward multiplier; audio is unaffected (GameSpeed.lua)
     speed = 1,
-    -- port display options (OptionsMenu / hotkeys 2/3/5)
+    -- port display options (OptionsMenu / hotkeys 2/3/4/5)
     colors = "gbc",
     tilt = 0,
     gbcfx = 0,
+    -- survey zoom offset from window fit scale (0 = FIT); see Zoom.lua
+    zoom = 0,
+    -- OVERWORLD beyond-edge fill: trees | water | black
+    voidFill = "trees",
     -- windowed | borderless (desktop fullscreen); ignored on mobile
     videoMode = "windowed",
     -- hard render frame-rate cap; render-only pacing (issue #88, FrameCap.lua)

src/render/BattleTransition.lua

@@ -230,6 +230,11 @@ function BattleTransition:draw()
 
   love.graphics.setColor(0, 0, 0, 1)
   local prog = math.min(1, self.t / self.wipeLen)
+  -- Cascade black 8x8 blocks across the window area *outside* the classic
+  -- 160x144 wipe square, in lockstep with the OG wipe progress.  Renderer
+  -- paints them in screen space after the world blit (see endFrame).
+  local renderer = self.game and self.game.renderer
+  if renderer then renderer.battleCascadeProg = prog end
   local style = self.style
 
   -- a registered style may draw itself; the eight built-ins do not

src/render/Renderer.lua

@@ -94,6 +94,8 @@ function Renderer:beginFrame(transparent)
   -- warp-fade overlay from Transition (issue #121); cleared each frame so
   -- a popped transition cannot leave a sticky black veil
   self.worldFadeAlpha = nil
+  -- battle-transition cascade outside the 160x144 wipe (BattleTransition)
+  self.battleCascadeProg = nil
   -- last frame's trueColor rects and sprite redraws go before anything
   -- draws this one
   PaletteFX.clearTrueColor()
@@ -107,6 +109,46 @@ function Renderer:beginFrame(transparent)
   end
 end
 
+-- Black 8x8 (scaled) blocks cascading outward from the classic GB letterbox
+-- into the surrounding window, matching BattleTransition wipe progress.
+-- Tiles that sit entirely inside the 160x144 square are left to the OG wipe.
+function Renderer:drawBattleCascade(prog, ww, wh, ox, oy, vpw, vph, S)
+  if not prog or prog <= 0 then return end
+  local TILE = 8 * S
+  if TILE < 1 then TILE = 1 end
+  local cols = math.ceil(ww / TILE)
+  local rows = math.ceil(wh / TILE)
+  local cx, cy = ox + vpw / 2, oy + vph / 2
+  local order = {}
+  for row = 0, rows - 1 do
+    for col = 0, cols - 1 do
+      local x, y = col * TILE, row * TILE
+      -- any tile with area outside the letterbox participates
+      if x < ox or y < oy or x + TILE > ox + vpw or y + TILE > oy + vph then
+        local dist = math.max(math.abs(x + TILE / 2 - cx),
+                              math.abs(y + TILE / 2 - cy))
+        order[#order + 1] = { x, y, dist }
+      end
+    end
+  end
+  if #order == 0 then return end
+  table.sort(order, function(a, b)
+    if a[3] ~= b[3] then return a[3] < b[3] end
+    if a[2] ~= b[2] then return a[2] < b[2] end
+    return a[1] < b[1]
+  end)
+  local n = math.floor(#order * math.min(1, prog) + 1e-6)
+  if prog >= 1 then n = #order end
+  love.graphics.setColor(0, 0, 0, 1)
+  love.graphics.setScissor(0, 0, ww, wh)
+  for i = 1, n do
+    local t = order[i]
+    love.graphics.rectangle("fill", t[1], t[2], TILE, TILE)
+  end
+  love.graphics.setScissor()
+  love.graphics.setColor(1, 1, 1, 1)
+end
+
 function Renderer:beginWorldPass()
   local vw, vh = self:worldViewSize()
   if not self.worldCanvas or self.worldCanvas:getWidth() ~= vw
@@ -349,7 +391,20 @@ function Renderer:endFrame(zones, worldZones)
     present = self.presentCanvas
     love.graphics.setCanvas(present)
   end
-  love.graphics.setColor(0, 0, 0, 1)
+  -- Default letterbox is black.  Battle (and any state that opts in via
+  -- letterboxWhite) fills the voids white so the window matches the
+  -- white battle canvas instead of showing black bars.
+  local clearR, clearG, clearB = 0, 0, 0
+  if not self.worldActive then
+    local ok, Game = pcall(require, "src.core.Game")
+    local stack = ok and Game and Game.stack
+    local base = stack and stack.visibleBase and stack:visibleBase()
+    local state = base and stack.states and stack.states[base]
+    if state and state.letterboxWhite then
+      clearR, clearG, clearB = 1, 1, 1
+    end
+  end
+  love.graphics.setColor(clearR, clearG, clearB, 1)
   love.graphics.rectangle("fill", 0, 0, ww, wh)
   love.graphics.setColor(1, 1, 1, 1)
 
@@ -460,6 +515,11 @@ function Renderer:endFrame(zones, worldZones)
       love.graphics.rectangle("fill", 0, 0, ww, wh)
       love.graphics.setColor(1, 1, 1, 1)
     end
+    -- Battle transition: cascade black blocks into the area outside the
+    -- classic 160x144 wipe square (world still shows through until filled).
+    if self.battleCascadeProg then
+      self:drawBattleCascade(self.battleCascadeProg, ww, wh, ox, oy, vpw, vph, S)
+    end
   end
   -- UI stays in the classic centered GB letterbox
   blit(self.canvas, S, zones, S, ox, oy, ox, oy, vpw, vph)

src/render/TileRenderer.lua

@@ -10,19 +10,57 @@ TileRenderer.__index = TileRenderer
 
 local BORDER_BLOCKS = 3 -- ring width; > half a screen (2.5 blocks)
 
--- OVERWORLD maps fill beyond-edge space with the solid tree wall
--- (blockset $0F: four regular-tree metatiles, tiles $40/$41/$50/$51, 
--- the border block of ViridianCity/CeruleanCity/CeladonCity et al.),
--- not each map's own border_block, which can be grass ($0B, the
--- CutTreeBlockSwaps $0B->$0A cut-grass block) or water; other
--- tilesets keep their designated border (interiors stay black/void)
+-- OVERWORLD maps fill beyond-edge space from save.options.voidFill:
+--   trees (default) — solid tree wall $0F (Viridian/Cerulean/Celadon)
+--   water           — solid water $43 (Cinnabar/Route 19 border block)
+--   black           — solid black (no tiled metatile)
+-- Other tilesets keep their designated border (interiors stay black/void).
 local TREE_WALL_BLOCK = 0x0F
+local WATER_BORDER_BLOCK = 0x43
+TileRenderer.VOID_FILLS = { "trees", "water", "black" }
+TileRenderer.voidFill = "trees"
+
 local function borderBlockFor(map)
-  if map.def.tileset == "OVERWORLD" then return TREE_WALL_BLOCK end
+  if map.def.tileset == "OVERWORLD" then
+    local mode = TileRenderer.voidFill or "trees"
+    if mode == "water" then return WATER_BORDER_BLOCK end
+    if mode == "black" then return false end
+    return TREE_WALL_BLOCK
+  end
   return map.def.borderBlock
 end
 TileRenderer.borderBlockFor = borderBlockFor
 
+function TileRenderer.setVoidFill(mode)
+  local ok = false
+  for _, m in ipairs(TileRenderer.VOID_FILLS) do
+    if m == mode then ok = true; break end
+  end
+  TileRenderer.voidFill = ok and mode or "trees"
+end
+
+function TileRenderer.cycleVoidFill()
+  local cur = TileRenderer.voidFill or "trees"
+  local idx = 1
+  for i, m in ipairs(TileRenderer.VOID_FILLS) do
+    if m == cur then idx = i; break end
+  end
+  TileRenderer.setVoidFill(
+    TileRenderer.VOID_FILLS[idx % #TileRenderer.VOID_FILLS + 1])
+  return TileRenderer.voidFill
+end
+
+function TileRenderer.applyOptions(opts)
+  TileRenderer.setVoidFill(opts and opts.voidFill or "trees")
+end
+
+function TileRenderer.voidFillLabel(mode)
+  mode = mode or TileRenderer.voidFill or "trees"
+  if mode == "water" then return "WATER" end
+  if mode == "black" then return "BLACK" end
+  return "TREES"
+end
+
 local imageCache = {}
 
 local function getImage(path)
@@ -487,42 +525,118 @@ function TileRenderer.new(map, data)
   self.anims = anims
   self.claimedBy = claimedBy
 
-  -- a repeating 32x32 image of the border block, tiled behind
-  -- everything the 3-block ring doesn't cover (the survey zoom sees
-  -- far past the ring; interiors keep their black border this way)
-  pcall(function()
-    local border = map.tileset.blocks[borderBlockFor(map) + 1]
-    if not border then return end
-    local canvas = love.graphics.newCanvas(32, 32)
-    love.graphics.push("all")
-    love.graphics.setCanvas(canvas)
-    love.graphics.clear(1, 1, 1, 1)
-    for ty = 0, 3 do
-      for tx = 0, 3 do
-        local quad = self.quads[border[ty * 4 + tx + 1]]
-        if quad then love.graphics.draw(self.image, quad, tx * 8, ty * 8) end
-      end
-    end
-    love.graphics.setCanvas()
-    love.graphics.pop()
-    local img = love.graphics.newImage(canvas:newImageData())
-    img:setWrap("repeat", "repeat")
-    img:setFilter("nearest", "nearest")
-    self.borderFill = img
-  end)
+  -- border-fill image is built lazily in :ensureBorderFill so a VOID FILL
+  -- option change can swap trees/water/black without reloading the map
+  self.borderFillMode = nil
+  self.borderFill = nil
 
   return self
 end
 
+-- Bake a static repeating 32x32 of `block` into self.borderFill.
+local function bakeBorderFill(self, block)
+  local border = self.map.tileset.blocks[block + 1]
+  if not border then return end
+  local canvas = love.graphics.newCanvas(32, 32)
+  love.graphics.push("all")
+  love.graphics.setCanvas(canvas)
+  love.graphics.clear(1, 1, 1, 1)
+  for ty = 0, 3 do
+    for tx = 0, 3 do
+      local quad = self.quads[border[ty * 4 + tx + 1]]
+      if quad then love.graphics.draw(self.image, quad, tx * 8, ty * 8) end
+    end
+  end
+  love.graphics.setCanvas()
+  love.graphics.pop()
+  local img = love.graphics.newImage(canvas:newImageData())
+  img:setWrap("repeat", "repeat")
+  img:setFilter("nearest", "nearest")
+  self.borderFill = img
+end
+
+-- WATER void fill: the eight hshift frames of tile $14 (same cycle as map
+-- water), wrap-tiled so the void scrolls in lockstep with on-map water.
+local function ensureWaterBorderFill(self)
+  if self.borderWaterTextures then return true end
+  local map = self.map
+  local perRow = map.tileset.tilesPerRow
+  local colors, gbcKey
+  if self.gbcAtlas and self.data then
+    local group = PaletteFX.worldGroupAt(map.tileset.id, map.id, WATER_TILE)
+    local groupColors = PaletteFX.worldGroupColors(
+      self.data, map.tileset.id, map.id, nil)
+    colors = group and groupColors and groupColors[group + 1] or nil
+    gbcKey = "#gbc:" .. map.id
+  end
+  local textures = getShiftVariants(map.tileset.image, perRow, WATER_TILE,
+                                    colors, gbcKey)
+  if not textures then return false end
+  for _, img in ipairs(textures) do
+    img:setWrap("repeat", "repeat")
+    img:setFilter("nearest", "nearest")
+  end
+  self.borderWaterTextures = textures
+  return true
+end
+
+-- (re)build the repeating border image when the VOID FILL mode or tileset
+-- choice changes.  OVERWORLD "black" leaves borderFill nil and draws a
+-- solid clear; "water" keeps the live hshift textures instead of a bake.
+function TileRenderer:ensureBorderFill()
+  local block = borderBlockFor(self.map)
+  local mode = block == false and "black"
+              or ((self.map.def.tileset == "OVERWORLD")
+                  and (TileRenderer.voidFill or "trees")
+                  or "map")
+  local ready = (mode == "black")
+                or (mode == "water" and self.borderWaterTextures)
+                or (mode ~= "water" and mode ~= "black" and self.borderFill)
+  if self.borderFillMode == mode and ready then return end
+  if self.borderFill and self.borderFill.release then
+    pcall(self.borderFill.release, self.borderFill)
+  end
+  self.borderFill = nil
+  -- shared shift-variant cache: drop the reference only, never release
+  self.borderWaterTextures = nil
+  self.borderFillMode = mode
+  if mode == "black" or block == false or block == nil then return end
+  if mode == "water" then
+    if ensureWaterBorderFill(self) then return end
+    -- headless / missing pixels: fall back to the static water block bake
+  end
+  pcall(bakeBorderFill, self, block)
+end
+
 -- tile the border block across the whole view (world-aligned so it
 -- meshes seamlessly with the ring batch)
 function TileRenderer:drawBorderFill(camX, camY, vw, vh)
-  if not self.borderFill then return end
+  self:ensureBorderFill()
+  if self.borderFillMode == "black" then
+    love.graphics.setColor(0, 0, 0, 1)
+    love.graphics.rectangle("fill", 0, 0, vw, vh)
+    love.graphics.setColor(1, 1, 1, 1)
+    return
+  end
   if self.trueColor then PaletteFX.markTrueColor(0, 0, vw, vh) end
   local x, y = math.floor(camX), math.floor(camY)
   -- one reused Quad per renderer, mutated in place: this runs every
   -- overworld frame, so allocating a fresh Quad here churned the GC
   local q = self.borderQuad
+  if self.borderFillMode == "water" and self.borderWaterTextures then
+    local step = math.floor(animFrame / ANIM_PERIOD) % #WATER_OFFSETS + 1
+    local tex = self.borderWaterTextures[WATER_OFFSETS[step] + 1]
+    if not tex then return end
+    if q then
+      q:setViewport(x, y, vw, vh, 8, 8)
+    else
+      q = love.graphics.newQuad(x, y, vw, vh, 8, 8)
+      self.borderQuad = q
+    end
+    love.graphics.draw(tex, q, 0, 0)
+    return
+  end
+  if not self.borderFill then return end
   if q then
     q:setViewport(x, y, vw, vh, 32, 32)
   else
@@ -730,6 +844,9 @@ function TileRenderer:releaseBatches()
   safeRelease(self.winBatch); self.winBatch = nil
   safeRelease(self.borderFill); self.borderFill = nil
   safeRelease(self.borderQuad); self.borderQuad = nil
+  -- shared shift-variant cache; only drop the reference
+  self.borderWaterTextures = nil
+  self.borderFillMode = nil
   self.win = nil
   if self.quads then
     for _, q in pairs(self.quads) do safeRelease(q) end

src/render/Zoom.lua

@@ -1,6 +1,7 @@
 -- Overworld survey zoom: integer pixels-per-world-pixel scales stepped
--- by the mouse wheel.  Stored as an offset from the window fit scale S
--- so a resize keeps the relative zoom.  Session-only; never saved.
+-- by the mouse wheel, Options ZOOM row, or hotkey `4`.  Stored as an
+-- offset from the window fit scale S so a resize keeps the relative
+-- zoom.  Persisted as save.options.zoom (default 0 = FIT).
 -- Spec: docs/new-features.md (survey zoom)
 
 local Zoom = {}
@@ -12,16 +13,51 @@ function Zoom.scale(S)
   return math.max(1, math.min(2 * S, S + Zoom.offset))
 end
 
+-- legal offset range for a given fit scale
+function Zoom.offsetRange(S)
+  S = math.max(1, math.floor(tonumber(S) or 1))
+  return 1 - S, S
+end
+
+function Zoom.clampOffset(offset, S)
+  local lo, hi = Zoom.offsetRange(S)
+  offset = math.floor(tonumber(offset) or 0)
+  if offset < lo then return lo end
+  if offset > hi then return hi end
+  return offset
+end
+
 function Zoom.step(delta, S)
-  Zoom.offset = Zoom.offset + delta
-  if S + Zoom.offset < 1 then Zoom.offset = 1 - S end
-  if S + Zoom.offset > 2 * S then Zoom.offset = S end
+  Zoom.offset = Zoom.clampOffset(Zoom.offset + delta, S)
+  return Zoom.offset
+end
+
+-- Advance one zoom level toward max close-up, then wrap to full survey.
+-- Returns the new offset.
+function Zoom.cycle(S)
+  local lo, hi = Zoom.offsetRange(S)
+  local next = Zoom.offset + 1
+  if next > hi then next = lo end
+  Zoom.offset = next
+  return Zoom.offset
 end
 
 function Zoom.reset()
   Zoom.offset = 0
 end
 
+function Zoom.applyOptions(opts)
+  Zoom.offset = math.floor(tonumber(opts and opts.zoom) or 0)
+end
+
+-- FIT / OUT1 / OUT2 / … / IN1 / IN2 / …
+function Zoom.offsetLabel(offset)
+  offset = math.floor(tonumber(offset) or 0)
+  if offset == 0 then return "FIT" end
+  if offset < 0 then return "OUT" .. tostring(-offset) end
+  return "IN" .. tostring(offset)
+end
+
 -- world pixels covered by a w x h letterbox viewport at fit scale S
 -- (legacy GB-framed size; prefer fillViewSize for the live world pass)
 function Zoom.viewSize(S, w, h)

src/ui/OptionsMenu.lua

@@ -3,7 +3,8 @@
 -- (cycles the merged rulesets registry; gen1_faithful keeps the original
 -- quirks), plus the port's audio rows and display rows: music/SFX
 -- volume (0-7), music low-pass filter (OFF/1X/2X/3X), COLORS / TILT /
--- GBC FX / VIDEO MODE, and the MODS row that opens the mod manager.
+-- GBC FX / ZOOM / VOID FILL / VIDEO MODE, and the MODS row that opens
+-- the mod manager.
 -- Rows are descriptors fed through the ui.options.rows hook, so mods can
 -- add their own; CANCEL is appended after the hook and stays fixed on the
 -- bottom line like pokered's.
@@ -11,12 +12,15 @@
 local PaletteFX = require("src.render.PaletteFX")
 local Tilt = require("src.render.Tilt")
 local GBCFX = require("src.render.GBCFX")
+local Zoom = require("src.render.Zoom")
+local TileRenderer = require("src.render.TileRenderer")
 local GameSpeed = require("src.core.GameSpeed")
 local VideoMode = require("src.core.VideoMode")
 local FrameCap = require("src.core.FrameCap")
 local Logger = require("src.core.Logger")
 local Runtime = require("src.mods.Runtime")
 local OptionRows = require("src.ui.OptionRows")
+local Renderer = require("src.render.Renderer")
 
 local OptionsMenu = {}
 OptionsMenu.__index = OptionsMenu
@@ -201,6 +205,37 @@ local function buildRows(game)
         GBCFX.setLevel(o.gbcfx)
         return true
       end },
+    { id = "zoom", label = "ZOOM",
+      value = function(g)
+        return Zoom.offsetLabel(g.save.options.zoom or 0)
+      end,
+      step = function(g, dir)
+        local o = g.save.options
+        local S = Renderer:fitScale()
+        local lo, hi = Zoom.offsetRange(S)
+        local off = (o.zoom or 0) + dir
+        if off > hi then off = lo
+        elseif off < lo then off = hi end
+        o.zoom = off
+        Zoom.offset = off
+        return true
+      end },
+    { id = "voidFill", label = "VOID FILL",
+      value = function(g)
+        return TileRenderer.voidFillLabel(g.save.options.voidFill)
+      end,
+      step = function(g, dir)
+        local o = g.save.options
+        local modes = TileRenderer.VOID_FILLS
+        local cur = o.voidFill or "trees"
+        local i = 1
+        for idx, m in ipairs(modes) do
+          if m == cur then i = idx; break end
+        end
+        o.voidFill = modes[wrapIndex(i - 1 + dir, #modes) + 1]
+        TileRenderer.setVoidFill(o.voidFill)
+        return true
+      end },
     { id = "videoMode", label = "VIDEO MODE",
       value = function(g)
         return VideoMode.modeLabel(g.save.options.videoMode)