sprite-forge

Sprite Forge

Generate game-ready sprites, SVG characters, ASCII art, animated mascots, and isometric turnarounds from images or text descriptions. Five output modes, each with proven pipelines.

When to Use

• Creating pixel-art characters or converting images to pixel art
• Generating sprite sheets with walk cycles, idle, attack animations
• Building 8-way isometric character turnarounds for tactics/RPG games
• Producing clean, hand-editable SVG characters or icons
• Converting images to ASCII/Unicode terminal art
• Animating mascots with GSAP walk, bounce, wave, or typing presets
• Generating lil-agents macOS dock companion videos

When not to use agents: Each pipeline is sequential — generate image, then process, then stitch. Work directly rather than spawning subagents, because intermediate outputs from one step feed the next. Parallel agents only help when generating multiple independent characters simultaneously.

Quick Start

# Isometric 8-way turnaround from a character image
python3 scripts/isometric_pipeline.py --reference character.png --output-dir ./iso/

# Video walk cycle → game sprite sheet with atlas
python3 scripts/video_to_spritesheet.py --input walk.mp4 --fps 12 --cell-size 64x64 --atlas json

# Image → pixel-art SVG mascot with walk animation
magick input.png -fuzz 15% -trim +repage /tmp/trimmed.png
python3 scripts/pixel_art_generator.py /tmp/trimmed.png --grid 20 --colors 4 --merge --remove-bg -o mascot.svg
python3 scripts/animation_builder.py --preset walk-and-bounce --svg-id mascot

# Image → terminal ASCII art
python3 scripts/image_to_ascii.py input.png --mode color --width 80

# Stitch frames into a sprite sheet with atlas
python3 scripts/stitch_spritesheet.py --input-dir frames/ --cols 8 --atlas json -o sheet.png

# Remove green screen background
python3 scripts/chroma_key.py --input sprite.png --output sprite_alpha.png --despill

Pipeline 1: Isometric Turnaround

Generate an 8-way directional character sprite from a single reference image. Based on chongdashu's FFT-style pipeline (github.com/chongdashu/vibe-isometric-sprites, Mar 2026).

Core insight: Never generate all 8 directions at once — generate 4 cardinals, then derive 4 diagonals.

python3 scripts/isometric_pipeline.py \
  --reference portrait.png \
  --character-desc "young adventurer, red scarf, blue tunic, leather belts" \
  --output-dir ./iso-output/ \
  --chroma-key

Steps orchestrated by the script:

1. Reference → full-body asset (identity anchor)
2. Full-body → isometric anchor (¾ view, facing down-right)
3. Apply chroma key green (#00FF00) for Nano Banana models
4. Generate 4 cardinal directions (N/E/S/W) as 2×2 sheet
5. Generate 4 diagonals (NE/NW/SE/SW) from anchor + cardinals
6. Optionally generate walk cycle via video model
7. Normalize, crop, stitch into final 8-direction sprite sheet

See references/isometric-turnaround.md for the full prompt library and model comparison.

Pipeline 2: Video to Sprite Sheet

Convert animation videos into game-ready sprite sheets. The proven approach for walk cycles because image models lack temporal coherence for multi-frame animation.

python3 scripts/video_to_spritesheet.py \
  --input walk_cycle.mp4 \
  --fps 12 --cell-size 64x64 \
  --remove-bg rembg \
  --cols 8 --atlas json \
  --output walk_sheet.png

Produces: walk_sheet.png + walk_sheet.json (atlas with frame coordinates for Phaser/Unity/Godot).

See references/video-to-spritesheet.md for practitioner workflows and engine integration.

Pipeline 3: SVG Character Generation

Two approaches depending on the output needed:

Gemini SVG-as-code — Clean, hand-editable vector SVGs with CSS custom properties. Gemini 3.1 Pro writes raw XML, not traced raster. Use for icons, logos, simple characters, interactive SVGs. Generate via nano-banana-pro with a prompt requesting SVG XML output. See references/gemini-svg-generation.md.

Pixel-art rect SVGs — Retro pixel-art characters built entirely from <rect> elements. Use when targeting GSAP animation or the ayotomcs-style mascot aesthetic.

magick input.png -fuzz 15% -trim +repage /tmp/trimmed.png
python3 scripts/pixel_art_generator.py /tmp/trimmed.png --grid 20 --colors 4 --merge --remove-bg -o char.svg

Design constraints for animatable pixel-art characters:

• Standing pose, side view — legs must be distinct blocks so walk cycle scaleY squash works on them independently
• 4-6 colors max — fewer colors produces cleaner quantization and more iconic, readable sprites at small sizes
• Symmetric body parts — left/right hand and leg pairs enable GSAP alternating animation without per-frame redrawing
• Grid size 16-24 — below 16 the character loses recognizable features; above 24 it stops reading as pixel art

See references/pixel-art-svgs.md for the rect conversion technique.

Pipeline 4: ASCII Art

Two sub-modes: static (image-to-ASCII conversion) and animated (frame-based ASCII animation components).

Static — Image to ASCII

Convert images to terminal-renderable character art.

# Grayscale density ramp
python3 scripts/image_to_ascii.py photo.png --mode gray --width 80

# Color Unicode half-block (▀▄█)
python3 scripts/image_to_ascii.py photo.png --mode color --width 120

# jp2a wrapper (if installed)
python3 scripts/image_to_ascii.py photo.png --mode jp2a --width 80

See references/ascii-art-techniques.md for character sets, density ramps, and color modes.

Animated — Frame-Based ASCII Animation Components

Generate React components that cycle through ASCII art frames at a target FPS. Output: TSX component with frame array, animation loop, APPEARANCE config, and ResizeObserver scaling. Distributable via shadcn registry.

Use when the user wants: animated ASCII art, terminal-style loading animations, retro text effects in a React app, ASCII art that moves.

Existing catalog (install via shadcn from asciistudio.space): Lightning, Skull, Pitstop, Red Fire, CD, Balls, Star, Rainbow Fire, Hand Fire, Dust. Install: npx shadcn@latest add https://asciistudio.space/r/<name>.json

Generating new animations: See references/ascii-animation-components.md for the component architecture, APPEARANCE config (video/gradient/burn effects), character sets, and generation guidelines. For programmatic patterns (particles, waves, fire), write a frame generator rather than hand-crafting each frame.

Pipeline 5: Animated Mascot

The ayotomcs-derived pipeline. Convert images to pixel-art SVG characters and animate with GSAP timelines.

# Generate SVG
python3 scripts/pixel_art_generator.py trimmed.png --grid 24 --colors 6 --merge --remove-bg -o mascot.svg

# Add animation preset
python3 scripts/animation_builder.py --preset walk-and-bounce --svg-id mascot

# Assemble standalone HTML demo
python3 scripts/animation_builder.py --preset walk-and-bounce --svg-id mascot --standalone -o mascot.html

Presets: idle, bounce, lean, wave, walk, walk-and-bounce, walk-and-wave, typing

Output formats: standalone (HTML + GSAP CDN), react (TSX component), svg-only (SMIL fallback)

Frame-by-frame: For complex choreography, generate N SVG frames as <g> groups, then use generate_frame_switcher() from animation_builder.py with variable timing.

lil-agents Dock Companion

Generate transparent HEVC walk cycle videos for the lil-agents macOS dock app:

python3 scripts/generate_walk_video.py spritesheet.png --cols 6 --name robot
# Output: walk-robot-01.mov (1080x1920, HEVC with alpha, ~10s)

See references/lil-agents-character-spec.md for the full format spec and references/gsap-timeline-patterns.md for animation recipes.

Model Selection Guide

| Task | Best Model | Why | |------|-----------|-----| | Identity preservation (anchor) | GPT Image 1.5 | Best at maintaining character features across edits | | Direction sheets (N/E/S/W) | Nano Bana