Stackchan Nukoevi Motion Assets

StackChan Nukoevi Motion Assets

Non-negotiables

• Final display frames are 320x240, landscape 4:3.
• Six-frame talk or sleep strips are 1920x240.
• Normal blink and sleepy avatar frames are runtime raw RGB565 .bin assets in the firmware assets partition, not app-partition C assets.
• Do not use LZ4-compressed assets for full-screen Nukoevi avatar frames. That path caused white-screen behavior on hardware.
• Use full flash, not app-flash, after changing runtime .bin assets or partitions.csv.
• Never use forced aspect distortion such as -resize 320x240! or -resize 1920x240!.
• Use aspect-preserving resize only. For generated 4:3 images, -resize 320x240 is enough. For uncertain inputs, use -resize 320x240^ -gravity center -extent 320x240.
• Do not invent the framing. Inspect the actual reference frames first.
• nukoevi-source.png is identity/style reference. It is not the framing reference for motion assets.
• nukoevi-blink-frame-0..3.png are the framing reference. The visible range is head, face, hat, ears, hair, and neck. Do not add chest or torso.
• Treat your own interpretation as suspect. If the user says the reference is neck-only, do not describe it as chest or body.

Important Paths

Repository:

/Users/username/ghq/github.com/schroneko/stackchan-nukoevi

Source assets:

firmware/main/apps/app_nukoevi/source-assets

Runtime assets:

firmware/main/assets/assets_bin

Generators and verifiers:

firmware/main/apps/app_nukoevi/source-assets/generate_nukoevi_motion_assets.py
firmware/main/apps/app_nukoevi/source-assets/verify_motion_asset.py

Runtime Usage

Blink runtime uses these raw RGB565 binaries:

firmware/main/assets/assets_bin/nukoevi-screen-open.bin
firmware/main/assets/assets_bin/nukoevi-screen-half-a.bin
firmware/main/assets/assets_bin/nukoevi-screen-closed.bin
firmware/main/assets/assets_bin/nukoevi-screen-half-b.bin

Talk runtime uses these binaries:

firmware/main/assets/assets_bin/nukoevi-talk-closed.bin
firmware/main/assets/assets_bin/nukoevi-talk-tiny.bin
firmware/main/assets/assets_bin/nukoevi-talk-medium.bin
firmware/main/assets/assets_bin/nukoevi-talk-wide.bin
firmware/main/assets/assets_bin/nukoevi-talk-small.bin
firmware/main/assets/assets_bin/nukoevi-talk-smile.bin

Sleep runtime uses these raw RGB565 binaries:

firmware/main/assets/assets_bin/nukoevi-sleep-drowsy.bin
firmware/main/assets/assets_bin/nukoevi-sleep-nearly-closed.bin
firmware/main/assets/assets_bin/nukoevi-sleep-nod.bin
firmware/main/assets/assets_bin/nukoevi-sleep-asleep.bin
firmware/main/assets/assets_bin/nukoevi-sleep-wobble.bin
firmware/main/assets/assets_bin/nukoevi-sleep-return.bin

These avatar .bin files use a 12 byte LVGL image header followed by 153600 bytes of RGB565 pixel data:

• magic: LV_IMAGE_HEADER_MAGIC
• color format: LV_COLOR_FORMAT_RGB565
• flags: 0
• size: 320x240
• stride: 0

Talk frames can stay LZ4-compressed because they are not used as the primary full-screen avatar image path.

The firmware assets partition is 5M in firmware/partitions.csv. If generated assets grow, check firmware/build/generated_assets.bin against that partition size before flashing.

PNG frames and strips are not read directly at runtime, but keep them because they are useful for review and regeneration.

Generation Workflow

1. Show the framing reference before generating:

magick firmware/main/apps/app_nukoevi/source-assets/nukoevi-blink-frame-0.png firmware/main/apps/app_nukoevi/source-assets/nukoevi-blink-frame-1.png firmware/main/apps/app_nukoevi/source-assets/nukoevi-blink-frame-2.png firmware/main/apps/app_nukoevi/source-assets/nukoevi-blink-frame-3.png +append /tmp/nukoevi-blink-reference-strip.png

View /tmp/nukoevi-blink-reference-strip.png.

2. Use the built-in image_gen skill/tool. Generate or edit from a single base image so that the character, crop, background, hat, ears, hair, and neck placement remain stable.

3. For talk, generate exactly six frames:

• frame 0: closed mouth
• frame 1: tiny open mouth
• frame 2: medium mouth
• frame 3: wide mouth
• frame 4: small rounded mouth
• frame 5: soft closed smile

Only the mouth should change.

4. For sleep, generate exactly six frames:

• frame 0: drowsy
• frame 1: nearly closed
• frame 2: closed eyes
• frame 3: asleep
• frame 4: one eye barely peeking
• frame 5: drowsy return

Only eyelids and tiny mouth expression should change. Do not change pose, background, head scale, crop, or costume.

5. Copy generated outputs from $CODEX_HOME/generated_images/... into project assets after inspection.

6. Write frames and strip:

magick input0.png -auto-orient -resize 320x240 firmware/main/apps/app_nukoevi/source-assets/nukoevi-talk-frame-0.png
magick input1.png -auto-orient -resize 320x240 firmware/main/apps/app_nukoevi/source-assets/nukoevi-talk-frame-1.png
magick input2.png -auto-orient -resize 320x240 firmware/main/apps/app_nukoevi/source-assets/nukoevi-talk-frame-2.png
magick input3.png -auto-orient -resize 320x240 firmware/main/apps/app_nukoevi/source-assets/nukoevi-talk-frame-3.png
magick input4.png -auto-orient -resize 320x240 firmware/main/apps/app_nukoevi/source-assets/nukoevi-talk-frame-4.png
magick input5.png -auto-orient -resize 320x240 firmware/main/apps/app_nukoevi/source-assets/nukoevi-talk-frame-5.png
magick firmware/main/apps/app_nukoevi/source-assets/nukoevi-talk-frame-0.png firmware/main/apps/app_nukoevi/source-assets/nukoevi-talk-frame-1.png firmware/main/apps/app_nukoevi/source-assets/nukoevi-talk-frame-2.png firmware/main/apps/app_nukoevi/source-assets/nukoevi-talk-frame-3.png firmware/main/apps/app_nukoevi/source-assets/nukoevi-talk-frame-4.png firmware/main/apps/app_nukoevi/source-assets/nukoevi-talk-frame-5.png +append firmware/main/apps/app_nukoevi/source-assets/nukoevi-talk-imagegen-strip.png

For sleep, replace talk with sleep.

7. Regenerate blink assets after changing normal blink frames:

uv run --with pillow python firmware/main/apps/app_nukoevi/source-assets/generate_nukoevi_blink_assets.py

8. Regenerate talk and sleep binaries and previews:

uv run --with pillow --with lz4 python firmware/main/apps/app_nukoevi/source-assets/generate_nukoevi_motion_assets.py

9. Verify:

magick identify -format '%f %wx%h ratio=%[fx:w/h]\n' firmware/main/apps/app_nukoevi/source-assets/nukoevi-talk-imagegen-strip.png firmware/main/apps/app_nukoevi/source-assets/nukoevi-talk-preview.png firmware/main/apps/app_nukoevi/source-assets/nukoevi-talk-frame-0.png firmware/main/apps/app_nukoevi/source-assets/nukoevi-talk-frame-1.png firmware/main/apps/app_nukoevi/source-assets/nukoevi-talk-frame-2.png firmware/main/apps/app_nukoevi/source-assets/nukoevi-talk-frame-3.png firmware/main/apps/app_nukoevi/source-assets/nukoevi-talk-frame-4.png firmware/main/apps/app_nukoevi/source-assets/nukoevi-talk-frame-5.png
uv run --with pillow python firmware/main/apps/app_nukoevi/source-assets/verify_motion_asset.py

Expected:

• frames are 320x240
• strip and preview are 1920x240
• verifier prints matches=True

10. Show the preview PNG before claiming success:

firmware/main/apps/app_nukoevi/source-assets/nukoevi-talk-preview.png
firmware/main/apps/app_nukoevi/source-assets/nukoevi-sleep-preview.png

Check for cropping, squeezing, scale drift, background drift, and identity drift.

Flashing

When the user asks for device reflection, build and flash from firmware:

. /Users/username/ghq/github.com/espressif/esp-idf/export.sh
idf.py build
idf.py -p /dev/tty.usbmodem3101 flash

Use full flash for asset or partition changes. app-flash is only enough for app-only changes.

Then monitor briefly:

gtimeout 20s zsh -lc '. /Users/username/ghq/github.com/espressif/esp-idf/export.sh
idf.py -p /dev/tty.usbmodem3101 monitor'

Confirm these lines appear when relevant:

• [NUKOEVI] on open
• blink assets loaded: ok
• sleep assets loaded: ok

Exit code 124 from gtimeout is expected if the log was captured.