headless-visual-verification

name	headless-visual-verification
description	Run autonomous visual checks for Rust4D rendering changes. Use after touching WGSL shaders, RenderUniforms, camera projection, slice pipeline, primitives, or examples that affect rendering.

Headless Visual Verification

Willow does not do manual rendering checks for this project. If a change affects visual output, verify it yourself with offscreen GPU captures.

Slice invariant protocol

Use for camera/movement/physics/slice correctness:

nix develop --command cargo run --example headless_protocol .scratchpad/captures

Read the [STATE] slice_w(...) logs. During WASD phases, slice W must remain constant. Convert frames with ImageMagick if needed.

Primitive showcase protocol

Use for geometry, shader, material, and lighting work:

nix develop --command cargo run --example shape_showcase .scratchpad/captures-gallery

Expected:

• 81 captures (9 primitives × 3 slice offsets × 3 orientations)
• zero zero-triangle captures
• no cracks/T-junctions/hairline seams
• central slices of every primitive visibly distinct

Make a quick contact sheet:

mkdir -p .scratchpad/captures-gallery/png
for f in .scratchpad/captures-gallery/*_mid_identity.ppm; do
    magick "$f" ".scratchpad/captures-gallery/png/$(basename "${f%.ppm}").png"
done
magick .scratchpad/captures-gallery/png/tesseract_mid_identity.png \
       .scratchpad/captures-gallery/png/hypersphere_mid_identity.png \
       .scratchpad/captures-gallery/png/pentachoron_mid_identity.png +append row1.png
# Repeat rows, then `magick row1.png row2.png row3.png -append contact-sheet.png`

Use +append/-append; ImageMagick montage may need fonts unavailable in the nix shell.

GPU warning

The current wgpu/naga stack may emit Vulkan validation warning VUID-StandaloneSpirv-MemorySemantics-10871 for OpAtomicIAdd relaxed semantics. This is harmless for now and tracked as a wgpu upgrade backlog item. Do not confuse it with a rendering failure.