feat(gamedev): comfyui_build_item_icon_workflow — iconos de inventario

Builder puro hermano de pixelart/sprite_sheet/seamless_tile: arma el dict
(API format) para iconos de items (espada/pocion/anillo/libro/escudo).
txt2img cuadrado + prompt scaffold de icono + LoRA estilo opcional + Rembg
(alpha). Compone comfyui_build_txt2img_workflow + comfyui_inject_lora.

Test offline 7/7 verde. Generacion real verificada (icono de pocion de
salud centrado, RGBA fondo recortado, prompt_id 70b7a52a, 512x512 SD1.5).
Fila en docs/capabilities/gamedev-2d.md. Detalle en report 0147.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

docs/capabilities/gamedev-2d.md

@@ -17,7 +17,7 @@ Filtro: `mcp__registry__fn_search query="" tag="gamedev-2d"`.
 Documento hermano del grupo `comfyui` (generación genérica de imágenes/video/3D).
 Diseño del puente: `docs/comfyui-godot-integration.md`. Planes origen: `reports/0135`
 (pixelart), `reports/0139` (entornos/tiles/iso), `reports/0137` (personajes/sprites),
-`reports/0140` (VFX), `reports/0143` (ronda 2b: builders).
+`reports/0140` (VFX), `reports/0143` (ronda 2b: builders), `reports/0147` (item icons).
 
 ## Builders de workflow 2D (`gamedev-2d`, puros — generación)
 
@@ -34,6 +34,7 @@ VFX (ver `reports/0143`).
 | `comfyui_build_isometric_workflow_py_ml` | `(positive, negative=…, *, iso_lora="isometric_game_assets_sd15…", grid_image=None, …) -> dict` | Asset iso 2:1: LoRA iso + ControlNet grid opcional. |
 | `comfyui_build_sprite_sheet_workflow_py_ml` | `(subject, *, ref_image=None, pose_skeleton=None, char_lora=None, transparent=True, …) -> dict` | UN sprite de personaje: IPAdapter-FaceID + LoRA + ControlNet OpenPose (Advanced, end<1) + Rembg. Varias poses → sheet. SD1.5. |
 | `comfyui_build_vfx_spritesheet_workflow_py_ml` | `(prompt, *, motion_model="mm_sd_v15_v2.ckpt", num_frames=16, closed_loop=True, lora=None, …) -> dict` | N frames AnimateDiff loop sobre negro (insumo de luma→alpha). 8GB: 16f@512² revienta, usar ≤8f@512² o bajar resolución. |
+| `comfyui_build_item_icon_workflow_py_ml` | `(item, *, style="game icon, clean, centered", checkpoint="dreamshaper_8…", size=512, transparent=True, lora=None, …) -> dict` | UN icono de item de inventario (espada/poción/anillo/libro/escudo): txt2img cuadrado + prompt scaffold de icono + LoRA estilo opcional + Rembg (alpha). Set coherente = mismo style/checkpoint/lora por item. SD1.5. |
 
 ## Funciones de post-proceso y puente (`gamedev`, CPU)
 

python/functions/ml/comfyui_build_item_icon_workflow.md

@@ -0,0 +1,104 @@
+---
+name: comfyui_build_item_icon_workflow
+kind: function
+lang: py
+domain: ml
+version: "1.0.0"
+purity: pure
+signature: "def comfyui_build_item_icon_workflow(item: str, *, style: str = \"game icon, clean, centered\", checkpoint: str = \"dreamshaper_8.safetensors\", size: int = 512, transparent: bool = True, seed: int = 0, lora: str | None = None, lora_strength: float = 1.0, rembg_model: str = \"u2net\", negative: str | None = None, steps: int = 28, cfg: float = 7.0, sampler_name: str = \"dpmpp_2m\", scheduler: str = \"karras\", filename_prefix: str = \"item_icon\") -> dict"
+description: "Construye el dict (API format) del workflow de UN icono de item de inventario 2D (espada, pocion, anillo, libro, escudo, gema): sujeto unico centrado, fondo limpio uniforme, estilo consistente entre items, encuadre cuadrado. Compone comfyui_build_txt2img_workflow + comfyui_inject_lora (estilo opcional) + Image Rembg (fondo transparente si transparent). Hermano de comfyui_build_pixelart/sprite_sheet/seamless_tile_workflow. Pura, sin red ni I/O. class_types verificados contra /object_info."
+tags: [comfyui, ml, gamedev, gamedev-2d, icon, item, inventory, rembg, workflow]
+uses_functions: [comfyui_build_txt2img_workflow_py_ml, comfyui_inject_lora_py_ml]
+uses_types: []
+returns: []
+returns_optional: false
+error_type: ""
+imports: []
+params:
+  - name: item
+    desc: "Nombre del item (ej. 'health potion', 'iron sword', 'gold ring'). Se inserta en un prompt scaffold de icono. No puede estar vacio."
+  - name: style
+    desc: "Descriptor de estilo que mantiene consistentes los items de un set (ej. 'game icon, clean, centered', 'hand-painted RPG icon', 'flat vector icon'). Pasa el MISMO style + checkpoint + lora a todos los items para coherencia visual. keyword-only."
+  - name: checkpoint
+    desc: "Checkpoint del servidor. 'dreamshaper_8.safetensors' (SD1.5, holgado en 8GB lowvram) por defecto; 'juggernaut_xl_v11.safetensors' para SDXL (mas VRAM, subir size). keyword-only."
+  - name: size
+    desc: "Lado del cuadrado en px (width = height = size). 512 SD1.5 por defecto. keyword-only."
+  - name: transparent
+    desc: "Si True inyecta Image Rembg y el PNG sale con alpha (fondo recortado). False = item opaco sobre fondo plano, recortable luego por el caller. keyword-only."
+  - name: seed
+    desc: "Semilla del KSampler. keyword-only."
+  - name: lora
+    desc: "LoRA de estilo opcional en models/loras (ej. 'detail_tweaker_sd15.safetensors', 'isometric_game_assets_sd15.safetensors'). None = sin LoRA. keyword-only."
+  - name: lora_strength
+    desc: "Fuerza del LoRA sobre model y clip. Se clampa a [0.0, 2.0]. keyword-only."
+  - name: rembg_model
+    desc: "Modelo Rembg ('u2net' general, 'isnet-anime' para anime). Solo se usa si transparent=True. keyword-only."
+  - name: negative
+    desc: "Prompt negativo. None usa el negativo por defecto pensado para iconos (un objeto, fondo limpio, sin texto/foto). keyword-only."
+  - name: steps
+    desc: "Pasos del KSampler. keyword-only."
+  - name: cfg
+    desc: "CFG del KSampler. keyword-only."
+  - name: sampler_name
+    desc: "Sampler del KSampler. keyword-only."
+  - name: scheduler
+    desc: "Scheduler del KSampler. keyword-only."
+  - name: filename_prefix
+    desc: "Prefijo del PNG en output/. keyword-only."
+output: "dict en API format listo para comfyui_submit_workflow: base txt2img cuadrada con prompt scaffold de icono ('a {item}, game inventory icon, {style}, centered, single object, plain background, ...') + LoRA de estilo opcional + Image Rembg (si transparent). UN icono; set de items -> llamar por item con mismo style/checkpoint/lora."
+tested: true
+tests: ["golden transparent: clases CheckpointLoaderSimple/KSampler/VAEDecode/SaveImage/Image Rembg; item + 'game inventory icon' + 'centered' en prompt; SaveImage <- Rembg; transparency True", "edge transparent=False: sin Rembg, SaveImage <- VAEDecode", "edge size: width==height==768 (cuadrado)", "edge style en prompt", "edge lora: LoraLoader presente con strength", "error item vacio -> ValueError", "determinismo"]
+test_file_path: "python/functions/ml/comfyui_build_item_icon_workflow_test.py"
+file_path: "python/functions/ml/comfyui_build_item_icon_workflow.py"
+---
+
+## Ejemplo
+
+```python
+import sys, os
+sys.path.insert(0, os.path.join(os.environ["HOME"], "fn_registry", "python", "functions"))
+from ml.comfyui_build_item_icon_workflow import comfyui_build_item_icon_workflow
+
+# Un icono de pocion con fondo transparente (alpha), listo para submit.
+wf = comfyui_build_item_icon_workflow(
+    "health potion",
+    style="hand-painted RPG icon, glowing red liquid",
+    transparent=True,
+    seed=42,
+)
+# Set coherente: misma firma de estilo para cada item del inventario.
+#   for it in ["iron sword", "gold ring", "ancient book", "wooden shield"]:
+#       wf = comfyui_build_item_icon_workflow(it, style="hand-painted RPG icon",
+#                                             lora="detail_tweaker_sd15.safetensors", seed=42)
+#       comfyui_submit_workflow(wf)  # -> comfyui_wait_result -> comfyui_fetch_output_image
+# Contact-sheet del set: montar los PNG resultantes con comfyui_build_grid.
+```
+
+O lanzable directo con: `./fn run comfyui_build_item_icon_workflow` (imprime nodos + class_types del ejemplo).
+
+## Cuando usarla
+
+Cuando necesites iconos de items de inventario para un juego (RPG, roguelike,
+crafting) con look consistente entre items: armas, pociones, anillos, libros,
+escudos, gemas, comida. Pasa el MISMO `style` + `checkpoint` + (`lora`) a todos
+los items del set para que combinen visualmente; varía solo `item`. `transparent`
+recorta el fondo (alpha) listo para el motor. Para un atlas/contact-sheet, genera
+cada icono y monta los PNG con `comfyui_build_grid`.
+
+## Gotchas
+
+- **El recorte usa Rembg, NO luma-to-alpha**: un item es un sujeto solido con
+  silueta definida, rembg lo recorta limpio. `comfyui_matting_luma_to_alpha` es
+  para translucidos sobre negro (humo/fuego/magia) y aplanaria el item — no la
+  uses para iconos.
+- **Coherencia del set = mismos parametros**: si cambias `style`/`checkpoint`/
+  `lora`/`seed` entre items, el set deja de combinar. Fija esos y varía solo `item`.
+- **SDXL pide mas VRAM y resolucion**: con `checkpoint="juggernaut_xl_v11.safetensors"`
+  sube `size` a 768/1024; con dreamshaper_8 (SD1.5) deja 512 (holgado en 8GB lowvram).
+- Si el modelo mete varios objetos o texto, el negativo por defecto ya empuja a
+  "single object / plain background / no text"; refuerza `style` con "single item,
+  isolated" si insiste.
+- `transparent=False` deja el item opaco sobre fondo plano: util si prefieres
+  recortar fuera del workflow o el motor compone sobre un slot solido.
+- Es una funcion **pura**: solo arma el dict. La generacion real (GPU) la hacen
+  `comfyui_submit_workflow` + `comfyui_wait_result` + `comfyui_fetch_output_image`.

python/functions/ml/comfyui_build_item_icon_workflow.py

@@ -0,0 +1,203 @@
+"""Construye el workflow ComfyUI de UN icono de item de inventario (API format).
+
+Iconos de inventario de juego (espada, pocion, anillo, libro, escudo, gema...):
+sujeto unico centrado, fondo limpio y uniforme, estilo consistente entre items,
+encuadre cuadrado. Es el builder hermano de comfyui_build_pixelart_workflow /
+comfyui_build_sprite_sheet_workflow / comfyui_build_seamless_tile_workflow:
+mismo patron (PURO, dict API format) que compone funciones existentes del
+registry, no reescribe el grafo.
+
+Cableado:
+
+    CheckpointLoaderSimple -> [LoraLoader opcional de estilo] -> KSampler
+                          -> CLIPTextEncode (prompt scaffold de icono) ...
+                          -> VAEDecode -> [Image Rembg opcional] -> SaveImage
+
+Compone:
+  - comfyui_build_txt2img_workflow  -> base txt2img cuadrada
+  - comfyui_inject_lora             -> LoRA de estilo opcional (consistencia)
+  - 'Image Rembg (Remove Background)' (helper local) -> fondo transparente
+
+Por que Rembg y NO comfyui_matting_luma_to_alpha: un item es un sujeto SOLIDO con
+silueta definida; rembg recorta limpio la silueta. La luma-to-alpha es para
+translucidos sobre negro (humo/fuego/magia), donde aplanaria el item. Si el caller
+prefiere recortar fuera del workflow (transparent=False) deja la imagen opaca
+sobre fondo plano, recortable luego por el pipeline o el caller.
+
+class_types/inputs verificados contra /object_info del servidor (8GB lowvram):
+CheckpointLoaderSimple, CLIPTextEncode, EmptyLatentImage, KSampler, VAEDecode,
+SaveImage, LoraLoader, 'Image Rembg (Remove Background)' (transparency BOOLEAN).
+
+Funcion pura: sin red, sin I/O. No muta dicts de entrada (copia profunda en el
+helper de rembg). Determinista para los mismos argumentos.
+"""
+from __future__ import annotations
+
+import copy
+import os
+import sys
+
+sys.path.insert(0, os.path.join(os.path.dirname(__file__), ".."))
+
+# Negativo por defecto pensado para iconos: un solo objeto, fondo limpio, nada de
+# fotorrealismo ni texto/marcas que ensucien el sujeto centrado.
+_ICON_NEGATIVE = (
+    "blurry, lowres, multiple objects, cluttered background, busy background, "
+    "text, watermark, signature, photo, photorealistic, jpeg artifacts, "
+    "cropped, out of frame, deformed"
+)
+
+
+def _inject_rembg(workflow: dict, model: str) -> dict:
+    """Inserta 'Image Rembg (Remove Background)' (transparency=True) entre VAEDecode y SaveImage.
+
+    Mismo helper que usa comfyui_build_sprite_sheet_workflow: el nodo recorta la
+    silueta del item dejando alpha. Repunta SaveImage.images a la salida del Rembg.
+    """
+    wf = copy.deepcopy(workflow)
+    vaedecode_id = next(
+        (nid for nid, n in wf.items() if n.get("class_type") == "VAEDecode"), None
+    )
+    save_id = next((nid for nid, n in wf.items() if n.get("class_type") == "SaveImage"), None)
+    if vaedecode_id is None or save_id is None:
+        raise ValueError(
+            "comfyui_build_item_icon_workflow: no se encontro VAEDecode/SaveImage para Rembg"
+        )
+    numeric = [int(k) for k in wf.keys() if str(k).isdigit()]
+    rembg_id = str((max(numeric) + 1) if numeric else len(wf) + 1)
+    wf[rembg_id] = {
+        "class_type": "Image Rembg (Remove Background)",
+        "inputs": {
+            "images": [vaedecode_id, 0],
+            "transparency": True,
+            "model": model,
+            "post_processing": False,
+            "only_mask": False,
+            "alpha_matting": False,
+            "alpha_matting_foreground_threshold": 240,
+            "alpha_matting_background_threshold": 10,
+            "alpha_matting_erode_size": 10,
+            "background_color": "none",
+        },
+    }
+    wf[save_id]["inputs"]["images"] = [rembg_id, 0]
+    return wf
+
+
+def comfyui_build_item_icon_workflow(
+    item: str,
+    *,
+    style: str = "game icon, clean, centered",
+    checkpoint: str = "dreamshaper_8.safetensors",
+    size: int = 512,
+    transparent: bool = True,
+    seed: int = 0,
+    lora: str | None = None,
+    lora_strength: float = 1.0,
+    rembg_model: str = "u2net",
+    negative: str | None = None,
+    steps: int = 28,
+    cfg: float = 7.0,
+    sampler_name: str = "dpmpp_2m",
+    scheduler: str = "karras",
+    filename_prefix: str = "item_icon",
+) -> dict:
+    """Construye el dict (API format) del workflow de un icono de item de inventario.
+
+    Args:
+        item: nombre del item (ej. "health potion", "iron sword", "gold ring").
+            Se inserta en un prompt scaffold de icono. No puede estar vacio.
+        style: descriptor de estilo que mantiene consistentes los items de un set
+            (ej. "game icon, clean, centered", "hand-painted RPG icon", "flat
+            vector icon"). Pasa el MISMO style + checkpoint + (lora) a todos los
+            items del set para coherencia visual. keyword-only.
+        checkpoint: checkpoint del servidor. 'dreamshaper_8.safetensors' (SD1.5,
+            holgado en 8GB lowvram) por defecto; 'juggernaut_xl_v11.safetensors'
+            para SDXL (mas VRAM, subir size a 768/1024). keyword-only.
+        size: lado del cuadrado en px (width = height = size). 512 SD1.5 por
+            defecto. keyword-only.
+        transparent: si True inyecta Rembg y el PNG sale con alpha (fondo
+            recortado). Si False deja el item opaco sobre fondo plano, recortable
+            luego por el caller/pipeline. keyword-only.
+        seed: semilla del KSampler. keyword-only.
+        lora: LoRA de estilo opcional en models/loras (ej.
+            'detail_tweaker_sd15.safetensors', 'isometric_game_assets_sd15.safetensors').
+            None = sin LoRA. keyword-only.
+        lora_strength: fuerza del LoRA sobre model y clip. Se clampa a [0.0, 2.0].
+            keyword-only.
+        rembg_model: modelo Rembg ('u2net' general, 'isnet-anime' para anime).
+            Solo se usa si transparent=True. keyword-only.
+        negative: prompt negativo. None usa el negativo por defecto pensado para
+            iconos (un objeto, fondo limpio, sin texto/foto). keyword-only.
+        steps, cfg, sampler_name, scheduler, filename_prefix: parametros de
+            generacion. keyword-only.
+
+    Returns:
+        dict en API format listo para comfyui_submit_workflow: txt2img base
+        cuadrada con prompt scaffold de icono + LoRA de estilo opcional + Rembg
+        (si transparent). Es UN icono; un set de items -> llamar por item con el
+        mismo style/checkpoint/lora y montar con comfyui_build_grid si se quiere.
+
+    Raises:
+        ValueError: si item esta vacio, o si la base no tiene VAEDecode/SaveImage
+            donde inyectar el Rembg (propagado por el helper).
+    """
+    from ml.comfyui_build_txt2img_workflow import comfyui_build_txt2img_workflow
+
+    if not item or not item.strip():
+        raise ValueError("comfyui_build_item_icon_workflow: 'item' no puede estar vacio")
+
+    lora_strength = max(0.0, min(2.0, float(lora_strength)))
+    neg = _ICON_NEGATIVE if negative is None else negative
+
+    # Prompt scaffold de icono: sujeto unico, centrado, fondo plano, sin recorte.
+    positive = (
+        f"a {item.strip()}, game inventory icon, {style}, centered, "
+        "single object, plain background, clean, high detail"
+    )
+
+    wf = comfyui_build_txt2img_workflow(
+        checkpoint,
+        positive,
+        neg,
+        steps=steps,
+        cfg=cfg,
+        width=size,
+        height=size,
+        seed=seed,
+        sampler_name=sampler_name,
+        scheduler=scheduler,
+        filename_prefix=filename_prefix,
+    )
+
+    if lora:
+        from ml.comfyui_inject_lora import comfyui_inject_lora
+
+        wf = comfyui_inject_lora(
+            wf, lora, strength_model=lora_strength, strength_clip=lora_strength
+        )
+
+    if transparent:
+        wf = _inject_rembg(wf, rembg_model)
+
+    return wf
+
+
+if __name__ == "__main__":
+    import json
+
+    wf = comfyui_build_item_icon_workflow(
+        "health potion",
+        style="hand-painted RPG icon, glowing red liquid",
+        transparent=True,
+        seed=42,
+    )
+    print(
+        json.dumps(
+            {
+                "nodes": list(wf),
+                "classes": sorted({n["class_type"] for n in wf.values()}),
+            },
+            indent=2,
+        )
+    )

python/functions/ml/comfyui_build_item_icon_workflow_test.py

@@ -0,0 +1,95 @@
+"""Tests offline de comfyui_build_item_icon_workflow (estructura del dict, sin GPU)."""
+
+import os
+import sys
+
+sys.path.insert(0, os.path.dirname(os.path.dirname(os.path.abspath(__file__))))
+from ml.comfyui_build_item_icon_workflow import (  # noqa: E402
+    comfyui_build_item_icon_workflow,
+)
+
+
+def _classes(wf):
+    return sorted({n["class_type"] for n in wf.values()})
+
+
+def _by_class(wf, cls):
+    return [n for n in wf.values() if n["class_type"] == cls]
+
+
+def _id_of(wf, cls):
+    return next(nid for nid, n in wf.items() if n["class_type"] == cls)
+
+
+def test_golden_transparent_recipe():
+    wf = comfyui_build_item_icon_workflow("health potion", transparent=True, seed=42)
+    cls = _classes(wf)
+    # Cadena base txt2img + Rembg para alpha.
+    assert "CheckpointLoaderSimple" in cls
+    assert "KSampler" in cls
+    assert "VAEDecode" in cls
+    assert "SaveImage" in cls
+    assert "Image Rembg (Remove Background)" in cls
+    # El item aparece en el prompt positivo, con el scaffold de icono.
+    pos = next(
+        n for n in wf.values()
+        if n["class_type"] == "CLIPTextEncode" and "health potion" in n["inputs"]["text"]
+    )
+    assert "game inventory icon" in pos["inputs"]["text"]
+    assert "centered" in pos["inputs"]["text"]
+    # SaveImage toma la imagen del Rembg (no del VAEDecode).
+    rembg_id = _id_of(wf, "Image Rembg (Remove Background)")
+    save = next(n for n in wf.values() if n["class_type"] == "SaveImage")
+    assert save["inputs"]["images"] == [rembg_id, 0]
+    assert _by_class(wf, "Image Rembg (Remove Background)")[0]["inputs"]["transparency"] is True
+
+
+def test_edge_opaque_no_rembg():
+    wf = comfyui_build_item_icon_workflow("iron sword", transparent=False)
+    assert "Image Rembg (Remove Background)" not in _classes(wf)
+    # SaveImage toma del VAEDecode directamente.
+    vd_id = _id_of(wf, "VAEDecode")
+    save = next(n for n in wf.values() if n["class_type"] == "SaveImage")
+    assert save["inputs"]["images"] == [vd_id, 0]
+
+
+def test_edge_size_reflected():
+    wf = comfyui_build_item_icon_workflow("gold ring", size=768)
+    latent = _by_class(wf, "EmptyLatentImage")[0]["inputs"]
+    assert latent["width"] == 768
+    assert latent["height"] == 768  # cuadrado
+
+
+def test_edge_style_in_prompt():
+    wf = comfyui_build_item_icon_workflow(
+        "ancient book", style="flat vector icon, minimalist", transparent=False
+    )
+    pos = next(
+        n for n in wf.values()
+        if n["class_type"] == "CLIPTextEncode" and "ancient book" in n["inputs"]["text"]
+    )
+    assert "flat vector icon, minimalist" in pos["inputs"]["text"]
+
+
+def test_edge_lora_reflected():
+    wf = comfyui_build_item_icon_workflow(
+        "magic shield", lora="detail_tweaker_sd15.safetensors", lora_strength=0.9
+    )
+    loras = _by_class(wf, "LoraLoader")
+    assert len(loras) == 1
+    assert loras[0]["inputs"]["lora_name"] == "detail_tweaker_sd15.safetensors"
+    assert loras[0]["inputs"]["strength_model"] == 0.9
+
+
+def test_error_empty_item():
+    try:
+        comfyui_build_item_icon_workflow("  ")
+        assert False
+    except ValueError as e:
+        assert "item" in str(e)
+
+
+def test_determinism():
+    a = comfyui_build_item_icon_workflow("emerald gem", lora="detail_tweaker_sd15.safetensors", seed=7)
+    b = comfyui_build_item_icon_workflow("emerald gem", lora="detail_tweaker_sd15.safetensors", seed=7)
+    assert a == b