moved route 1 battle location again, added transparency to bottom battle menu

lib/ImageCache.lua

@@ -0,0 +1,65 @@
+-- Voxel world mode: decoded pixels, kept.
+--
+-- Assets.imageData is deliberately uncached upstream -- "pixel-level reads
+-- resolve the same way but stay uncached: the caller keeps the derived
+-- product" (src/render/Assets.lua) -- which is the right contract for the
+-- flat renderer, whose one caller decodes a strip once and keeps the strip.
+--
+-- This mod is not that caller. It reads the same handful of images over and
+-- over, from several places that do not know about each other:
+--
+--   * the tileset atlas, decoded by Structures (its own cache), by
+--     TerrainAtlas twice (the SGB bake and the RED++ rebake), by
+--     TerrainAtlas again to learn a tile's shades, and by GlassMask;
+--   * the FLOWER FRAME files, decoded inside patch() -- which runs every
+--     time the animation step turns over, about three times a second, for
+--     as long as the map is on screen. That one is not a load cost at all,
+--     it is a recurring per-second cost on the render thread, and it was
+--     the single clearest waste the first profile turned up.
+--
+-- So: one table, keyed by the path as the CALLER gave it, holding the
+-- decoded ImageData. Registered with Assets.invalidate so a hot reload
+-- drops it alongside every other downstream cache.
+--
+-- The entries are never evicted by size. That is deliberate and bounded:
+-- what lands here is tileset art and animation frames -- a few dozen small
+-- images for a whole session, tens of kilobytes each -- not per-map bakes,
+-- which have their own eviction in TerrainAtlas.setLive.
+
+-- the mod namespace (see main.lua): V.require loads a sibling module
+local V = ...
+
+local Assets = require("src.render.Assets")
+local Perf = V.require("Perf")
+
+local ImageCache = {}
+
+local cache = {}
+
+-- The decoded pixels for `path`, or nil when it cannot be read.
+--
+-- `false` is cached for an unreadable path, so a missing or corrupt asset
+-- costs one failed decode for the session rather than one per frame -- the
+-- same sticky-failure shape the rest of this mod uses for GPU objects.
+function ImageCache.get(path)
+  if not path then return nil end
+  local hit = cache[path]
+  if hit ~= nil then
+    Perf.count("imageCache.hit")
+    return hit or nil
+  end
+  local t0 = Perf.now()
+  local ok, data = pcall(Assets.imageData, path)
+  Perf.add("ImageCache.decode", t0)
+  Perf.count("imageCache.miss")
+  cache[path] = (ok and data) or false
+  return cache[path] or nil
+end
+
+function ImageCache.invalidate()
+  cache = {}
+end
+
+Assets.register(ImageCache.invalidate)
+
+return ImageCache