initial commit

src/render/Font.lua

@@ -0,0 +1,116 @@
+-- Text renderer using the real extracted font sheets and charmap.
+-- font.png holds glyph codes $80-$FF, font_extra.png $60-$7F (borders etc).
+-- The charmap is matched greedily (longest sequence first) so multi-byte
+-- UTF-8 chars and ligature glyphs like 'd 'l 's map to single glyphs.
+
+local Font = {}
+
+local state
+
+function Font.load(data)
+  local def = data.font
+  local main = love.graphics.newImage(def.image)
+  local extra = love.graphics.newImage(def.imageExtra)
+  state = {
+    def = def,
+    main = main,
+    extra = extra,
+    mainQuads = {},
+    extraQuads = {},
+    byFirstByte = {},
+  }
+  local function buildQuads(img, quads)
+    local iw, ih = img:getDimensions()
+    local perRow = iw / 8
+    for i = 0, perRow * (ih / 8) - 1 do
+      quads[i] = love.graphics.newQuad((i % perRow) * 8,
+                                       math.floor(i / perRow) * 8, 8, 8, iw, ih)
+    end
+  end
+  buildQuads(main, state.mainQuads)
+  buildQuads(extra, state.extraQuads)
+  -- charmap comes sorted longest-first from the extractor; bucket by first
+  -- byte for fast greedy matching
+  for _, entry in ipairs(def.charmap) do
+    local b = entry.seq:byte(1)
+    state.byFirstByte[b] = state.byFirstByte[b] or {}
+    table.insert(state.byFirstByte[b], entry)
+  end
+end
+
+-- Convert a text string into a list of glyph codes.  Unknown characters
+-- render as space (and are reported once).
+local reported = {}
+function Font.encode(text)
+  local codes = {}
+  local i = 1
+  while i <= #text do
+    local candidates = state.byFirstByte[text:byte(i)]
+    local matched = false
+    if candidates then
+      for _, entry in ipairs(candidates) do
+        local n = #entry.seq
+        if text:sub(i, i + n - 1) == entry.seq then
+          codes[#codes + 1] = entry.code
+          i = i + n
+          matched = true
+          break
+        end
+      end
+    end
+    if not matched then
+      local ch = text:sub(i, i)
+      if not reported[ch] and ch:byte() >= 32 then
+        reported[ch] = true
+        require("src.core.Logger").warn("font: no glyph for %q", ch)
+      end
+      codes[#codes + 1] = 0x7F -- space
+      i = i + 1
+    end
+  end
+  return codes
+end
+
+function Font.drawCode(code, x, y)
+  local def = state.def
+  if code >= def.mainBase then
+    love.graphics.draw(state.main, state.mainQuads[code - def.mainBase], x, y)
+  elseif code >= def.extraBase then
+    love.graphics.draw(state.extra, state.extraQuads[code - def.extraBase], x, y)
+  end
+end
+
+-- Draw a plain single-line string at pixel (x, y).
+function Font.draw(text, x, y)
+  local codes = Font.encode(text)
+  for i, code in ipairs(codes) do
+    Font.drawCode(code, x + (i - 1) * 8, y)
+  end
+  return #codes * 8
+end
+
+-- Border glyph codes (font_extra.png, from charmap.asm $79-$7E)
+Font.BORDER = {
+  tl = 0x79, h = 0x7A, tr = 0x7B, v = 0x7C, bl = 0x7D, br = 0x7E,
+}
+
+-- Draw a Game Boy style bordered box in tile coordinates.
+function Font.drawBox(tx, ty, tw, th)
+  love.graphics.setColor(1, 1, 1, 1)
+  love.graphics.rectangle("fill", tx * 8, ty * 8, tw * 8, th * 8)
+  local B = Font.BORDER
+  Font.drawCode(B.tl, tx * 8, ty * 8)
+  Font.drawCode(B.tr, (tx + tw - 1) * 8, ty * 8)
+  Font.drawCode(B.bl, tx * 8, (ty + th - 1) * 8)
+  Font.drawCode(B.br, (tx + tw - 1) * 8, (ty + th - 1) * 8)
+  for i = 1, tw - 2 do
+    Font.drawCode(B.h, (tx + i) * 8, ty * 8)
+    Font.drawCode(B.h, (tx + i) * 8, (ty + th - 1) * 8)
+  end
+  for j = 1, th - 2 do
+    Font.drawCode(B.v, tx * 8, (ty + j) * 8)
+    Font.drawCode(B.v, (tx + tw - 1) * 8, (ty + j) * 8)
+  end
+end
+
+return Font