sprite-generation

Sprite Generation Skill

PROBLEM

LLM-based sprite generation (PIL, Grok, MiniMax without proper workflow) produces garbage:

• 2/10 quality sprites
• Horizontal gaps between body parts
• Checkerboard artifacts
• Misalignment
• General-purpose image gen ≠ pixel art

RIGHT APPROACH (from wiki research)

Tier 1: BEST QUALITY - ComfyUI SDXL + Pixel Art LoRA

System: RTX 4090, ComfyUI 0.20.1, 22GB VRAM
Checkpoint: sd_xl_base_1.0.safetensors
LoRA: pixel_icon_v1.safetensors (or Pixel Art Stylizer SDXL)

Workflow:
CheckpointLoaderSimple → LoraLoader (strength=1.0)
  → CLIPTextEncode (positive + negative) 
  → EmptyLatentImage (128x128)
  → KSampler (steps=25, cfg=8.0, euler)
  → VAEDecode
  → Quantize (cap at 64-256 colors)
  → SaveImage

Generation time: ~2 seconds on RTX 4090

Tier 2: BEST FREE - Pollinations.ai

• 256x256 sprites
• Respects size parameters (unlike Grok)
• Free, no GPU needed
• Use k-means post-process: alpha-binarize FIRST, then k-means k=24-32

Tier 3: HYBRID (what we've been trying)

• Generate body parts separately via LLM
• Composite with LPC sprites
• THIS APPROACH FAILS - wiki explicitly says "body parts pipeline = failed approach"
• Don't use PIL-based generation - produces simple geometric shapes, not pixel art

WHAT DOESN'T WORK

• ❌ PIL ImageDraw generation (simple shapes, not art)
• ❌ Grok API (ignores size params, returns 1408x768)
• ❌ General LLM image gen without pixel art LoRA
• ❌ k-means without alpha-binarize first (destroys colors)
• ❌ Body parts pipeline (failed approach per wiki)

WORKING ASSETS ALREADY AVAILABLE

• Cordon CC0: 205 sci-fi sprites at 128x128 in assets/cordon/temp_cordon/sprites/
• LPC Sprites: assets/generated/body_parts/ (if properly generated)
• Procedural drawPixelCharacter(): Works in game_demo.html

DECISION TREE

1. Need sprites NOW? → Use Cordon CC0 assets or procedural fallback
2. Want quality pixel art? → Use ComfyUI SDXL + pixel_icon_v1 LoRA
3. Free only? → Use Pollinations.ai with proper prompting
4. Don't use: PIL generation, Grok, body parts pipeline

PROPER PROMPTING FOR POLLINATIONS

"pixel art, 128x128, knight walk cycle, 8 frames, side view,
transparent background, limited color palette 24 colors,
pixel-perfect edges, no anti-aliasing, no gradients,
medieval armor, fantasy RPG sprite"

POST-PROCESSING (if using LLM output)

1. Alpha-binarize (threshold transparency)
2. k-means palette reduction (k=24-32 for 128x128)
3. Nearest-neighbor upscale if needed
4. Manual cleanup in Aseprite (5 sec/frame)

REFERENCES

• Wiki: ~/llm_wiki/wiki/sources/comfyui-pixel-art-sprite-pipeline-2026-05-01.md
• Wiki: ~/llm_wiki/wiki/sources/sprite-generation-learnings-2026-05-01.md
• Wiki: ~/llm_wiki/wiki/sources/pixel-art-ai-generation-research-2026-05-01.md