Support variable-size anchored overworld sprites

docs/architecture.md

@@ -38,7 +38,7 @@ the same core data and graphics into the source tree for verification.
 | | `src/core/SaveData.lua` | Lua-serialized save in the LÖVE save dir |
 | render | `src/render/Renderer.lua` | 160x144 canvas, integer nearest scaling |
 | | `src/render/TileRenderer.lua` | one SpriteBatch per map (8x8 quads) + border-block ring |
-| | `src/render/SpriteRenderer.lua` | 6-frame walker sheets, flipped right facing |
+| | `src/render/SpriteRenderer.lua` | variable-size anchored sprite sheets, 6-frame walkers and flipped right facing |
 | | `src/render/Font.lua` | glyph rendering via charmap (greedy longest match) |
 | | `src/render/TextBox.lua` | dialogue box: typewriter, `\n` line, `\v` scroll, `\f` page |
 | | `src/render/Camera.lua`, `Transition.lua` | follow camera, warp fades |

docs/modding.md

@@ -100,6 +100,44 @@ Three rules worth knowing:
 Returning `nil` from `drawWorld` is a normal answer meaning "not this
 frame"; the engine draws the vanilla world instead.
 
+## Variable-size overworld sprites
+
+The `sprites` registry keeps the vanilla 16x16 grounded walker as its default,
+but a mod can describe any frame rectangle and anchor for player characters,
+NPCs, followers, mounts, vehicles, bosses, or other field actors:
+
+```lua
+mod.content.sprites:register("SPRITE_COMPANION", {
+  image = "mods/example/companion.png", -- one frame per row
+  frames = 6,
+  walker = true,
+  frameWidth = 32,
+  frameHeight = 32,
+  anchorX = 16, -- frame-relative bottom-center anchor
+  anchorY = 32,
+})
+```
+
+`frameWidth` and `frameHeight` are sheet pixels. `anchorX` and `anchorY` are
+measured from each frame's top-left; when omitted they default to the frame's
+horizontal center and bottom edge, so a larger sprite grows upward while its
+feet stay on the same world cell. Omitting all four fields is exactly the
+vanilla 16x16 placement. The normal player/NPC/follower draw paths consume
+these values automatically, including horizontal flips and the fishing pose.
+
+Custom render pipelines can use the same geometry without reproducing the
+pose rules:
+
+```lua
+local geometry = sprite:getPoseGeometry(facing, walkPhase, stepFlip)
+-- geometry.quad, .x/.y/.width/.height, .anchorX/.anchorY, .mirror
+local originX, originY = sprite:getScreenOrigin(px, py, camX, camY)
+```
+
+`getFrameGeometry(frame)` is the corresponding accessor for a specific
+zero-based sheet frame. Both accessors return fresh tables and share the
+renderer’s frame selection and mirror conventions.
+
 ## Battle sprite scaling
 
 The enemy's front pic draws at 1x and the player's back pic at 2x, the way

src/mods/Schemas.lua

@@ -592,6 +592,13 @@ R.sprites = {
     image = f.path,
     frames = f.int(1),
     walker = f.opt(f.bool),
+    -- Optional sheet geometry for mod actors.  Defaults match the vanilla
+    -- 16x16 grounded walker; anchors are measured from each frame's
+    -- top-left in pixels (default: bottom-center).
+    frameWidth = f.opt(f.int(1)),
+    frameHeight = f.opt(f.int(1)),
+    anchorX = f.opt(f.num),
+    anchorY = f.opt(f.num),
     trueColor = f.opt(f.bool),
     -- Mod art can opt into an existing ROM sprite's Advanced-mode OBJ
     -- palette assignment without claiming that the image itself came from

src/render/SpriteRenderer.lua

@@ -1,7 +1,8 @@
--- Overworld character sprites.  A 12-tile sheet (16x96 PNG) holds 6 16x16
--- frames: stand down/up/left, walk down/up/left (data/sprites/facings.asm).
+-- Overworld character sprites.  The vanilla 12-tile sheet (16x96 PNG) holds
+-- 6 16x16 frames: stand down/up/left, walk down/up/left
+-- (data/sprites/facings.asm).  Mod records may opt into another frame size
+-- and anchor; the defaults below preserve the original grounded placement.
 -- Right-facing frames are horizontal flips of the left frames.
--- Sprites draw 4px above their cell, like the GB engine.
 
 local Assets = require("src.render.Assets")
 local PaletteFX = require("src.render.PaletteFX")
@@ -76,6 +77,58 @@ local WALK = { down = 3, up = 4, left = 5, right = 5 }
 SpriteRenderer.STAND = STAND
 SpriteRenderer.WALK = WALK
 
+-- Sprite records are anchored at the point where the actor stands in the
+-- world.  In the vanilla renderer that point is the bottom-center of a
+-- 16x16 frame: the frame starts at (px, py - 4), so the ground point is
+-- (px + 8, py + 12).  Custom anchors are measured from the frame's top-left
+-- in sheet pixels and may be fractional for a sub-pixel art style.
+local DEFAULT_FRAME_WIDTH = 16
+local DEFAULT_FRAME_HEIGHT = 16
+local DEFAULT_ANCHOR_X = 8
+local DEFAULT_ANCHOR_Y = 16
+local WORLD_ANCHOR_X = 8
+local WORLD_ANCHOR_Y = 12
+SpriteRenderer.DEFAULT_FRAME_WIDTH = DEFAULT_FRAME_WIDTH
+SpriteRenderer.DEFAULT_FRAME_HEIGHT = DEFAULT_FRAME_HEIGHT
+SpriteRenderer.DEFAULT_ANCHOR_X = DEFAULT_ANCHOR_X
+SpriteRenderer.DEFAULT_ANCHOR_Y = DEFAULT_ANCHOR_Y
+
+local function finiteNumber(value)
+  if type(value) ~= "number" or value ~= value
+     or value == math.huge or value == -math.huge then
+    return nil
+  end
+  return value
+end
+
+local function positiveInteger(value, fallback)
+  value = finiteNumber(value)
+  if value and value >= 1 then return math.floor(value) end
+  return fallback
+end
+
+local function numberOr(value, fallback)
+  return finiteNumber(value) or fallback
+end
+
+local function pose(self, facing, walkPhase, stepFlip)
+  if self.frameCount <= 1 then return 0, false end
+  local frame = (self.def.walker and walkPhase == 1)
+                and WALK[facing] or STAND[facing]
+  frame = frame or 0
+  -- Preserve the old fallback for a short custom sheet whose pose table
+  -- names a frame it does not provide.
+  if not self.frames[frame] then frame = 0 end
+  local flip = false
+  if facing == "right" then
+    flip = true
+  elseif (facing == "down" or facing == "up")
+         and walkPhase == 1 and stepFlip then
+    flip = true
+  end
+  return frame, flip
+end
+
 -- seed: any stable per-instance value (e.g. an NPC's `id`) used to resolve
 -- RED++'s per-instance "random" OBP sentinel (PaletteFX.spriteObp)
 function SpriteRenderer.new(spriteDef, seed)
@@ -83,14 +136,62 @@ function SpriteRenderer.new(spriteDef, seed)
   self.def = spriteDef
   self.seed = seed
   self.image = getImage(spriteDef.image)
+  self.frameCount = positiveInteger(spriteDef.frames, 1)
+  self.frameWidth = positiveInteger(spriteDef.frameWidth, DEFAULT_FRAME_WIDTH)
+  self.frameHeight = positiveInteger(spriteDef.frameHeight, DEFAULT_FRAME_HEIGHT)
+  self.anchorX = numberOr(spriteDef.anchorX, self.frameWidth / 2)
+  self.anchorY = numberOr(spriteDef.anchorY, self.frameHeight)
   local iw, ih = self.image:getDimensions()
   self.frames = {}
-  for f = 0, spriteDef.frames - 1 do
-    self.frames[f] = love.graphics.newQuad(0, f * 16, 16, 16, iw, ih)
+  for f = 0, self.frameCount - 1 do
+    self.frames[f] = love.graphics.newQuad(0, f * self.frameHeight,
+                                           self.frameWidth, self.frameHeight,
+                                           iw, ih)
   end
   return self
 end
 
+-- Return the sheet rectangle and top-left-relative anchor for a frame.  The
+-- result is a fresh table so a custom render pipeline may annotate it without
+-- changing the renderer's shared definition.
+function SpriteRenderer:getFrameGeometry(frame)
+  frame = math.floor(finiteNumber(frame) or 0)
+  if frame < 0 then frame = 0 end
+  if frame >= self.frameCount then frame = self.frameCount - 1 end
+  return {
+    frame = frame,
+    x = 0,
+    y = frame * self.frameHeight,
+    width = self.frameWidth,
+    height = self.frameHeight,
+    anchorX = self.anchorX,
+    anchorY = self.anchorY,
+    quad = self.frames[frame],
+  }
+end
+
+-- Return the frame geometry selected by the ordinary 2D pose rules, plus the
+-- horizontal mirror state that :draw applies.  This is the supported hook for
+-- custom render pipelines that need to draw actors with the same pose/flip.
+function SpriteRenderer:getPoseGeometry(facing, walkPhase, stepFlip)
+  local frame, flip = pose(self, facing, walkPhase, stepFlip)
+  local geometry = self:getFrameGeometry(frame)
+  geometry.facing = facing
+  geometry.walkPhase = walkPhase
+  geometry.stepFlip = stepFlip
+  geometry.mirror = flip
+  return geometry
+end
+
+-- Screen-space top-left for the actor's current world anchor.  World-facing
+-- effects such as fishing can use this instead of assuming a 16x16 frame.
+function SpriteRenderer:getScreenOrigin(px, py, camX, camY)
+  local baseX = math.floor(px - camX) + WORLD_ANCHOR_X
+  local baseY = math.floor(py - camY) + WORLD_ANCHOR_Y
+  return math.floor(baseX - self.anchorX),
+         math.floor(baseY - self.anchorY)
+end
+
 -- The image this sprite would draw from right now: the plain sheet, or the
 -- OBP-recolored bake of it.  Exposed so a render pipeline can texture its
 -- own geometry from the very same image -- the geometry carries sheet pixel
@@ -125,27 +226,32 @@ end
 
 -- facing: down/up/left/right; walkPhase: 0 stand, 1 walk; flip: alternate
 -- steps mirror the walk frame for up/down (GB uses OAM flip for this).
-local function blitFrame(image, quad, x, y, flip, redraw)
+local function blitFrame(image, quad, x, y, flip, redraw, frameWidth)
+  frameWidth = frameWidth or DEFAULT_FRAME_WIDTH
   if flip then
-    love.graphics.draw(image, quad, x + 16, y, 0, -1, 1)
-    if redraw then PaletteFX.markSpriteRedraw(image, quad, x + 16, y, -1) end
+    love.graphics.draw(image, quad, x + frameWidth, y, 0, -1, 1)
+    if redraw then
+      PaletteFX.markSpriteRedraw(image, quad, x + frameWidth, y, -1)
+    end
   else
     love.graphics.draw(image, quad, x, y)
     if redraw then PaletteFX.markSpriteRedraw(image, quad, x, y, 1) end
   end
 end
 
--- topHalf blits only the upper 8 rows of the frame: FishingAnim overwrites the
--- bottom tile row of the standing frames with the fishing pose art, which the
--- caller then draws itself through :drawTile (Player:draw, #384)
+-- topHalf blits everything above the bottom 8-pixel tile row: FishingAnim
+-- overwrites that row of the standing frames with fishing pose art, which the
+-- caller then draws itself through :drawTile (Player:draw, #384).  Vanilla
+-- frames therefore still draw 8 rows, while taller frames keep their larger
+-- body and reserve only the overlay row.
 function SpriteRenderer:draw(px, py, camX, camY, facing, walkPhase, stepFlip, topHalf)
-  local x = math.floor(px - camX)
-  local y = math.floor(py - camY) - 4
+  local x, y = self:getScreenOrigin(px, py, camX, camY)
   local image = self.image
   local redraw = false
-  -- full-color art claims its 16x16 cell out of the shade-remap pass
+  -- True-color sheets bypass every palette bake; the screen-space exemption
+  -- is recorded below once the final frame/height is known.
   if self.def.trueColor then
-    PaletteFX.markTrueColor(x, y, 16, 16)
+    image = self.image
   elseif PaletteFX.usesGbcPack() then
     -- RED++: the world canvas is already true-color (TileRenderer bakes
     -- terrain, this bakes the sprite) and the world pass runs unshaded
@@ -177,31 +283,28 @@ function SpriteRenderer:draw(px, py, camX, camY, facing, walkPhase, stepFlip, to
     -- being colorized by the zone IS the point (#301).
     image = getObpImage(self.def.image, PaletteFX.dmgObj())
   end
-  -- single-frame sprites (item balls, fossils...) have one fixed pose;
+  -- Single-frame sprites (item balls, fossils...) have one fixed pose;
   -- still 3-frame sprites turn to face (the nurse at her machine,
-  -- facePlayer on STAY NPCs) but never show walk frames
-  if self.def.frames <= 1 then
-    blitFrame(image, self.frames[0], x, y, false, redraw)
-    return
-  end
-  local frame = (self.def.walker and walkPhase == 1)
-                and WALK[facing] or STAND[facing]
-  local flip = false
-  if facing == "right" then
-    flip = true
-  elseif (facing == "down" or facing == "up") and walkPhase == 1 and stepFlip then
-    flip = true
-  end
-  local quad = self.frames[frame] or self.frames[0]
-  if topHalf then
+  -- facePlayer on STAY NPCs) but never show walk frames.
+  local frame, flip = pose(self, facing, walkPhase, stepFlip)
+  local quad = self.frames[frame]
+  local drawHeight = self.frameHeight
+  if topHalf and self.frameCount > 1 then
     self.halfFrames = self.halfFrames or {}
     if not self.halfFrames[frame] then
       local iw, ih = self.image:getDimensions()
-      self.halfFrames[frame] = love.graphics.newQuad(0, frame * 16, 16, 8, iw, ih)
+      local topHeight = math.max(1, self.frameHeight - math.min(8, self.frameHeight))
+      self.halfFrames[frame] = love.graphics.newQuad(
+        0, frame * self.frameHeight, self.frameWidth, topHeight, iw, ih)
     end
     quad = self.halfFrames[frame]
+    drawHeight = math.max(1, self.frameHeight - math.min(8, self.frameHeight))
   end
-  blitFrame(image, quad, x, y, flip, redraw)
+  -- Full-color art claims exactly the portion of the frame that was drawn.
+  if self.def.trueColor then
+    PaletteFX.markTrueColor(x, y, self.frameWidth, drawHeight)
+  end
+  blitFrame(image, quad, x, y, flip, redraw, self.frameWidth)
 end
 
 -- Blit a loose 16-wide fx tile at screen (x, y) wearing THIS sprite's OBJ
@@ -225,7 +328,7 @@ function SpriteRenderer:drawTile(path, x, y, flip)
   self.tileQuads = self.tileQuads or {}
   self.tileQuads[path] = self.tileQuads[path]
                          or love.graphics.newQuad(0, 0, iw, ih, iw, ih)
-  blitFrame(image, self.tileQuads[path], x, y, flip, redraw)
+  blitFrame(image, self.tileQuads[path], x, y, flip, redraw, iw)
 end
 
 return SpriteRenderer

src/world/OverworldController.lua

@@ -81,8 +81,10 @@ local HEAL_FLASH_MAP = { [0] = 0, [1] = 2, [2] = 1, [3] = 3 }
 -- above (screen = tile*8 + pixel - 8/16), measured against the player
 -- sprite's fixed screen spot: ResetPlayerSpriteData parks it at $3c/$40
 -- (home/reset_player_sprite.asm), i.e. screen (64,60).  So what ports over
--- is the delta from the sprite's top-left, which SpriteRenderer:draw puts at
--- (px, py - 4).  `tile` indexes the three stacked 8x8 tiles of
+-- is the delta from the sprite's top-left, which the vanilla
+-- SpriteRenderer:draw puts at (px, py - 4); custom frame anchors move that
+-- origin while keeping these offsets frame-relative.  `tile` indexes the
+-- three stacked 8x8 tiles of
 -- assets/generated/fx/fishing_rod.png: FishingRodOAM only ever draws $fd
 -- (row 0, up/down) and $fe (row 1, left/right), and RIGHT is the LEFT tile
 -- x-flipped.  Blitting the whole 8x24 sheet is what drew the rod as a
@@ -4799,9 +4801,15 @@ function OverworldState:drawWorld()
           end
         end
         local quad = self.rodQuads[oam.tile]
-        -- the sprite's top-left is 4px above its cell (SpriteRenderer:draw)
-        local rx = p.px - cam.x + oam.dx
-        local ry = p.py - cam.y - 4 + oam.dy
+        -- Place the rod against the active sprite's anchored top-left.  The
+        -- vanilla result is still (px-cam, py-cam-4), while custom larger
+        -- sheets keep the rod attached to their feet.
+        -- Fishing always uses the on-foot player sheet; read its fields
+        -- directly so this FX pass does not advance pose-side animation.
+        local sprite, px, py = p.sprite, p.px, p.py
+        local sx, sy = sprite:getScreenOrigin(px, py, cam.x, cam.y)
+        local rx = sx + oam.dx
+        local ry = sy + oam.dy
         love.graphics.setColor(1, 1, 1, 1)
         if quad and oam.flip then
           love.graphics.draw(self.rodImg, quad, rx + 8, ry, 0, -1, 1)

src/world/Player.lua

@@ -335,8 +335,13 @@ function Player:draw(camX, camY)
   local fishTile = self.fishing and self.fishTiles and self.fishTiles[facing]
   if fishTile then
     sprite:draw(px, py, camX, camY, facing, 0, false, true)
-    sprite:drawTile(fishTile, math.floor(px - camX),
-                    math.floor(py - camY) - 4 + 8, facing == "right")
+    -- The fishing pose replaces the bottom 8-pixel tile.  Use the sprite's
+    -- actual anchored frame origin so larger/custom sheets keep the pose at
+    -- their feet instead of falling back to the vanilla 16x16 top-left.
+    local sx, sy = sprite:getScreenOrigin(px, py, camX, camY)
+    sprite:drawTile(fishTile, sx,
+                    sy + math.max(0, sprite.frameHeight - 8),
+                    facing == "right")
     return
   end
   sprite:draw(px, py, camX, camY, facing, phase, flip)

tests/mod_graphics_tests.lua

@@ -428,16 +428,42 @@ local spriteReg = Registry.new("sprites", Schemas.REGISTRIES.sprites)
 spriteReg:register("SPRITE_TITLE_LOGO",
                    { image = "mods/logo/logo.png", frames = 1,
                      trueColor = true }, "logo_mod")
+spriteReg:register("SPRITE_LARGE_ACTOR",
+                   { image = "mods/actor/actor.png", frames = 6,
+                     walker = true, frameWidth = 32, frameHeight = 24,
+                     anchorX = 16, anchorY = 24, trueColor = true },
+                   "actor_mod")
 local logoDef = spriteReg:get("SPRITE_TITLE_LOGO")
 check(Schemas.check(Schemas.REGISTRIES.sprites, "sprites", "SPRITE_TITLE_LOGO",
                     logoDef, "register"),
       "a trueColor sprites record validates against the catalog schema")
 check(logoDef.trueColor == true, "and keeps the flag through the merge")
+local largeDef = spriteReg:get("SPRITE_LARGE_ACTOR")
+check(Schemas.check(Schemas.REGISTRIES.sprites, "sprites", "SPRITE_LARGE_ACTOR",
+                    largeDef, "register"),
+      "a variable-size sprites record validates against the catalog schema")
 
 Renderer:init()
 local plainSprite = SpriteRenderer.new(
   { image = "assets/generated/sprites/red.png", frames = 1 })
 local litSprite = SpriteRenderer.new(logoDef)
+local largeSprite = SpriteRenderer.new(largeDef)
+check(plainSprite.frameWidth == 16 and plainSprite.frameHeight == 16
+      and plainSprite.anchorX == 8 and plainSprite.anchorY == 16,
+      "legacy sprite definitions keep the vanilla frame geometry")
+local frameGeometry = largeSprite:getFrameGeometry(5)
+check(frameGeometry.frame == 5 and frameGeometry.x == 0
+      and frameGeometry.y == 120 and frameGeometry.width == 32
+      and frameGeometry.height == 24 and frameGeometry.anchorX == 16
+      and frameGeometry.anchorY == 24,
+      "frame geometry exposes a larger sheet rectangle and anchor")
+local poseGeometry = largeSprite:getPoseGeometry("right", 1, true)
+check(poseGeometry.frame == 5 and poseGeometry.mirror == true
+      and poseGeometry.quad == largeSprite.frames[5],
+      "pose geometry follows walker frame selection and right mirroring")
+local originX, originY = largeSprite:getScreenOrigin(32, 32, 0, 0)
+check(originX == 24 and originY == 20,
+      "a custom anchor keeps a larger sprite grounded at its cell")
 
 Renderer:beginFrame(true)
 check(#PaletteFX.trueColorRects("ui") == 0
@@ -471,6 +497,27 @@ check(#worldDrawn == 2, "the reported zone joins the world list endFrame blits")
 check(worldDrawn[1].shader and worldDrawn[2].shader == false,
       "the colorized pass runs first, then the sprite's rect with no shader")
 
+-- Larger true-color frames claim their actual extent, and fishing's top-half
+-- path reserves only the bottom 8-pixel tile for the overlay.
+Renderer:beginFrame(true)
+Renderer:beginWorldPass()
+largeSprite:draw(32, 32, 0, 0, "down", 0, false)
+local largeRects = PaletteFX.trueColorRects("world")
+check(#largeRects == 1 and largeRects[1].x == 24 and largeRects[1].y == 20
+      and largeRects[1].w == 32 and largeRects[1].h == 24,
+      "a larger trueColor sprite reports its full anchored extent")
+Renderer:endWorldPass()
+
+Renderer:beginFrame(true)
+Renderer:beginWorldPass()
+largeSprite:draw(32, 32, 0, 0, "down", 0, false, true)
+local topRects = PaletteFX.trueColorRects("world")
+check(#topRects == 1 and topRects[1].h == 16
+      and largeSprite.halfFrames[0].y == 0
+      and largeSprite.halfFrames[0].h == 16,
+      "the fishing overlay keeps a larger frame's bottom tile clear")
+Renderer:endWorldPass()
+
 -- the same path on the UI canvas, which is where a full-color title logo
 -- or menu portrait lands
 Renderer:beginFrame(false)