[Pixel Post] Level‑Up Your Pixel Art: Walk‑Cycle Animation with Flux, IP‑Adapter V2 & ControlNet (2025 Guide)

TL;DR – Feed two or three clean reference sprites + a stick‑figure pose frame into Flux.1, crank the IP‑Adapter dial to ~0.8 and the ControlNet (pose) dial to ~1.1, iterate for eight frames, then stitch the PNGs into a sprite sheet. You just animated a character while your coffee was still hot.

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Why Flux?

• Native pixel‑art bias. Flux.1’s rectified‑flow backbone loves hard‑edged sprites; it doesn’t hallucinate watercolours the way SD‑XL sometimes does. (huggingface.co)

• Speed. The Schnell variant gets a 64 × 64 frame out in ~0.6 s on a mid‑tier GPU.

• Drop‑in adapters. Former DreamBooth chores are now one‑click IP‑Adapter loads – no fine‑tunes, no 10‑GB checkpoints. (huggingface.co)

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Stuff You Need

Add Python ≥ 3.10 and diffusers 0.28 if you’d rather script it.

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Step 1 – Prep Your Reference Frames

1. Pick 2–3 clean sprites. Front idle, three‑quarter idle, maybe a jump frame. Transparent PNG, no background cruft.

2. Upscale 4× (nearest‑neighbour). Keeps the pixel grid crisp while giving the adapter something to chew on.

3. Double‑check colour palette. IP‑Adapter loves to copy colours verbatim – good for consistency, embarrassing for stray UI magenta.

Tip: Flux works fine with 64 × 64 refs; no need for 512 monsters. The adapter will down‑sample anyway.

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Step 2 – Get Your Walk‑Cycle Silhouettes

• Grab an 8‑frame walk template (Aseprite → File ▸ Export ▸ PNG Sequence).

• Set background to pure white, character to solid black – OpenPose reads edges, not art.

• Export each frame as pose_00.png … pose_07.png.

If you’re lazy, import your sprite into ase‑pose‑helper (free) and auto‑trace stick figures.

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Step 3 – Install the Toybox

# 1. ComfyUI (if you don't already have it)
git clone https://github.com/comfyanonymous/ComfyUI.git
cd ComfyUI && python -m venv venv && . venv/bin/activate
pip install -r requirements.txt

# 2. Flux checkpoint (drop into models/checkpoints)
wget https://huggingface.co/black-forest-labs/FLUX.1-dev/resolve/main/flux1_dev.safetensors

# 3. Flux IP‑Adapter node
comfyui --add-node XLabs-AI/flux-ip-adapter-v2

# 4. ControlNet‑Union‑Pro
comfyui --add-node Shakker-Labs/FLUX.1-dev-ControlNet-Union-Pro-2.0

(Windows folk: drag‑and‑drop the .json node bundles into the manager, click Install, done.)

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Step 4 – Build the Graph

1. Checkpoint Loader → flux1_dev.safetensors

2. IP‑Adapter‑Flux Node

   • Input images: ref_idle.png, ref_jump.png

   • Scale: 0.80

3. Flux Preprocess – DWPose

   • Image: pose_00.png

4. Flux ControlNet (Union‑Pro 2.0, mode=pose)

   • Weight: 1.10

   • Guidance End: 0.65

5. (Optional) PuLID‑FLUX

   • Weight: 0.75

6. K‑Sampler

   • Euler‑a, 24 steps, CFG 5.0

7. Save Image

Hit Generate.

Hand drift? Bump ControlNet to 1.25. Colours washed‑out? Nudge IP‑Adapter scale to 0.9.

Repeat for each pose_XX.png.

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Step 5 – Automate with Diffusers (Loop‑All‑Frames)

from diffusers import AutoPipelineForText2Image, FluxControlNetModel
import torch, glob, PIL.Image as Image

pipe = AutoPipelineForText2Image.from_pretrained(
        "black-forest-labs/FLUX.1-schnell", torch_dtype=torch.float16).to("cuda")
# Pose ControlNet
pipe.controlnet = FluxControlNetModel.from_pretrained(
        "Shakker-Labs/FLUX.1-dev-ControlNet-Union-Pro-2.0",
        subfolder="pose", torch_dtype=torch.float16).to("cuda")
# IP‑Adapter
pipe.load_ip_adapter("XLabs-AI/flux-ip-adapter-v2"); pipe.set_ip_adapter_scale(0.8)
ref_imgs = [Image.open(p) for p in ("ref_idle.png", "ref_jump.png")]

for pose_path in sorted(glob.glob("pose_*.png")):
    frame = pipe(
        prompt="32px pixel art character, clean outline, flat colours, no background",
        negative_prompt="blur, extra limbs, watermark",
        ip_adapter_image=ref_imgs,
        control_image=Image.open(pose_path),
        controlnet_conditioning_scale=1.1,
        num_inference_steps=20,
        guidance_scale=5.0,
    ).images[0]
    frame.save(pose_path.replace("pose_", "walk_"))

Eight files later and you have walk_00.png … walk_07.png.

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Step 6 – Stitch a Sprite Sheet

from PIL import Image
frames = [Image.open(f"walk_{i:02}.png") for i in range(8)]
w, h = frames[0].size
sheet = Image.new("RGBA", (w*8, h))
for i, fr in enumerate(frames):
    sheet.paste(fr, (i*w, 0))
sheet.save("walk_cycle.png")

Drop walk_cycle.png into Aseprite, set Frame Duration = 100 ms, press Play. Boom – looping animation.

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Common Gotchas

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Final Thoughts

What used to take a week of onion‑skinning in Aseprite now takes fifteen minutes and a GPU. Flux + IP‑Adapter V2 locks your character, Union‑Pro nails the pose, and a tiny Python loop spits out the frames. Spend the time you saved on coffee, new level designs, or – dare I say – shipping the game.

Go forth and animate. And remember: if your sprite can walk, your game can run.