[charliehuge]

Adds hunter_bird, a FundingCAPTCHA shader Setup that draws the blob tracker's notes as a bird hunting visitors, and the groundwork it needs: a design mockup, a blobs channel source for the shader player (ADR-0022), and the spec and plan. The Setup is in the rotation and plays for 120 s.

What's in it

1. The hunter_bird Setup — ShowControl/FundingCAPTCHA/shaders/hunter_bird/

• Buffer B holds the bird's state for each slot: interest, lock, which person it has struck, its reticle, mood, blinks, and footprints.
  • The bird strikes each person once, then ignores them.
  • Lock builds only when motion is above LOCK_ON (0.65) and the person is staying put: each slot's velocity, low-passed over 1.5 s, must be near zero. A walker's stride swings their box as much as waving arms do, so drift is what tells walking from flailing. Walking at any speed or stride tested never strikes; flailing strikes in 2.4–4.2 s.
  • A target whose blob is missed for a camera frame keeps the bird; it isn't handed to a rival.
  • A person who stands still loses the reticle. The box is smoothed before its size change is measured, so a still person escapes up to ±8 px of box jitter per side.
• Image draws the world (ground, footprints, people with hatching, canopy), the field notes and reticle, the strike stamp with its punch-in, and the eye (iris band, lids, blink membrane).
  • Pixels hidden by the lids skip the world, and footprints stop at a slot's first dead print. Both are for Pi frame rate.
• All tuning is in common.glsl constants.
• docs/FundingCAPTCHA.md lists the Setup in "Setups in rotation".

2. Design mockup — docs/superpowers/specs/2026-11-04-hunter-bird-mockup.html

• A runnable canvas sketch of the approved look and behaviour. Open it in a browser; it has a scrubber.

3. A blobs channel source for the shader player (ADR-0022, amends ADR-0021)

• Setups bind "blobs" and read an 8×3 RGBA32F texture with texelFetch. Each slot holds a box, centroid and velocity, an id, a state (tentative, confirmed, coasting or lost) and seconds in that state. A slot stays with the same person for that person's whole track.
• body_blobs.py finds blobs in the Body itself, so boxes line up with the silhouette, and tracks them with BlobStabilizer in Body pixels. It runs at camera rate, and only while the current Setup reads blobs. Boxes are eased at render rate between camera frames. Tunables are in shader_app.blobs.
• BlobStabilizer.update_tracks() reports every live track, its detection, and the ids that expired. update() is unchanged.
• shaders/blob_painter.glsl stands in for the tracker in Shadertoy. On the Pi, --test-input reads the painted Body back from the GPU and runs the real tracker on it.
• shaders/blob_debug/ is a reference reader. It isn't in the rotation.
• Fix: the keyboard texture was an integer texture that every shader read as 0, so Shift, Space and C never worked in --test-input.
• The body painter's head now overlaps its torso, so the real tracker sees a painted person as one blob instead of two.
• scipy is now always required by shader_app.py.
• Rotation resets the tracker on every load and R reload, so a Setup's fresh buffers never meet ids it already acted on.

4. Spec and plan

• docs/superpowers/specs/2026-11-04-hunter-bird-design.md records the design decisions.
• docs/superpowers/plans/2026-11-04-hunter-bird.md is the seven-task build plan this PR carries out.

Testing

• test_hunter_bird.py has 45 tests. They run the real Body tracker on synthetic masks (walking, flailing, flickering, pacing, still, two people, a jittering still person) with a fake clock: camera at 10 Hz, render at 30 Hz.
• make test: 398 passed. The GL tests also pass on Mesa llvmpipe (EGL_PLATFORM=surfaceless LIBGL_ALWAYS_SOFTWARE=1) as well as NVIDIA.
• An adversarial review found no merge blockers; its findings are fixed in the last commit.
• The mock camera ran for 2 minutes at 30 fps, the app's cap, on a desktop.
• Both tabs compile as GLSL ES 3.00 in Shadertoy's tab order.

Not yet verified

• Real camera. Run with --camera on site. Someone standing still for 5 s should lose the reticle; someone flailing should be stamped within about 3 s.
• Pi 5 frame rate, for the Setup and for tracking. Tracking is about 2.5 ms per camera frame on desktop x86.
• Shadertoy. Nothing has been pasted in; no browser was available.
• A by-eye tuning pass. Rendered frames were checked, but nothing was tuned by hand.

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