Audit prop budgets and add a prop-gallery art check

- audit_glb decodes geometry: 400 tris / 600 verts budget, degenerate
  triangles, UV range, ground contact, one material; newspaper box parts moved
  to sit on y=0
- capture_prop_gallery.gd renders the six props on a studio backdrop; new
  prop_gallery catalogue entry + AI mockup (compare 10 good, judge match 0.90)
- headless test that instances share the imported atlas material
- README documents the gallery capture and budget; TODO props pipeline section
  moved to DONE

DONE.md

@@ -734,3 +734,21 @@ Completed 2026-11-01 (v0.4.0). Headless **187/187**, Python tooling **53/53**, t
       remove collision; a unit test covers the fallback body, shape, width, and navigation obstacle.
 - [x] Tests: placement validation and its failure modes, variant determinism/range, colliders on
       every placed prop (including obstacle presence), and the fallback collider path.
+
+## Prop Pipeline Checks
+
+Completed 2026-11-01. Python tooling **56/56**, headless **188/188**, prop gallery **match**
+(0.90) in the vision judge, `compare` **10 good / 0 bad**.
+
+- [x] `audit_glb()` now decodes positions/UVs/indices and enforces the art budget
+      (`MAX_TRIANGLES = 400`, `MAX_VERTICES = 600`), rejects degenerate triangles, UVs outside
+      `[0, 1]`, a prop that floats above or sinks below the ground (`min y ~= 0`), and the
+      single-material/atlas contract. The newspaper box sat 3 cm high; its catalogue parts moved
+      down so it rests on y = 0.
+- [x] Added `capture_prop_gallery.gd`: renders all six props on a studio backdrop (two rows on a
+      display platform) to `docs/screenshots/10-prop-gallery.png`, with a `prop_gallery`
+      catalogue entry and AI mockup, so `compare`/`judge` cover close-range prop art.
+- [x] Confirmed instances share the imported atlas material (headless test) and documented the
+      triangle/vertex budget in the pipeline docstring.
+- [x] README lists the gallery capture command and image; the pipeline docstring and audit docs
+      describe the budget checks.

MEMORY.md

@@ -52,6 +52,9 @@ Session memory for durable decisions, state, and gotchas. Keep concise, remove o
   flat plane, so avoidance (not a baked mesh) routes guests around props. Placements live in
   `PROP_PLACEMENTS` with `placement_problems()` validation; variants come from `variant_for(index)`.
   `smoke_props.gd` must be windowed because the guard reads captured-mouse input.
+- **Prop pipeline (done):** audit enforces 400 tris / 600 verts, ground contact, UV range, no
+  degenerate tris, one material. `capture_prop_gallery.gd` writes `10-prop-gallery.png` (3x2 studio
+  line-up, back row on a platform) and the `prop_gallery` catalogue entry compares it.
 - **Presentation pass remaining (TODO):** NPC characters and player movement. Grounding facts: the
   NPC rig is rigid capsules with a whole-limb swing, and `guard_controller.gd` uses one `accel`
   value. Each task should get its own windowed smoke or capture where it changes feel/looks.

README.md

@@ -14,9 +14,9 @@ The central design goal is simple:
 | ![Access inspection: wristband/credential check with allow/deny prompt](docs/screenshots/03-access-inspection.png) | ![Radio report form: emergency dispatch panel](docs/screenshots/04-radio-report.png) |
 | ![Late night: street lamps lit, marquee glowing, dark Hollywood Boulevard](docs/screenshots/05-late-night-avenue.png) | ![Night shift: guard flashlight cutting through the dark](docs/screenshots/06-night-flashlight.png) |
 | ![Wand screening at The Joke Shop: false alarm on keys](docs/screenshots/07-wand-screening.png) | ![Escalation HUD at L3 with body camera armed and reaction log](docs/screenshots/08-escalation-hud.png) |
-| ![Body-camera timeline: formal warning, body camera on, blocking](docs/screenshots/09-body-camera-timeline.png) | |
+| ![Body-camera timeline: formal warning, body camera on, blocking](docs/screenshots/09-body-camera-timeline.png) | ![Prop gallery: the six generated street-furniture models on a studio backdrop](docs/screenshots/10-prop-gallery.png) |
 
-*Screenshots are generated by [`src/test/capture_screenshots.gd`](src/test/capture_screenshots.gd) from the current build — day, late-night, wand screening, escalation, and shift-review timeline.*
+*Screenshots are generated by [`src/test/capture_screenshots.gd`](src/test/capture_screenshots.gd) and [`src/test/capture_prop_gallery.gd`](src/test/capture_prop_gallery.gd) from the current build — day, late-night, wand screening, escalation, shift-review timeline, and the prop lineup.*
 
 ## ⬇️ Downloads
 
@@ -248,6 +248,9 @@ python3 tools/screen_designs.py generate --draft --only wand --force
 # (requires OPENROUTER_API_KEY)
 python3 tools/screen_designs.py generate
 
+# Prop gallery (studio line-up) for close-range prop checks
+godot --path . --script res://src/test/capture_prop_gallery.gd
+
 # Compare docs/screenshots/*.png against the designs
 python3 tools/screen_designs.py compare
 python3 tools/screen_designs.py compare --json

TODO.md

@@ -5,20 +5,8 @@ suite **187/187** plus **53** Python tooling tests; the session, PLAN-verb, crow
 timeline, audio, scenario-content, props, and windowed focus/radial smokes pass. Anonymous
 downloads are enabled on the host.
 
-The sections below are the rest of the presentation pass: prop pipeline checks, NPC characters,
-and player movement. Each task is meant to be a small, reviewable slice with its own verification.
-
-## Better Props
-
-### Pipeline and checks
-
-- [ ] Extend `audit_glb()` with a triangle budget, degenerate-triangle test, `TEXCOORD_0` inside
-      the atlas, minimum-y ≈ 0, and a material-count check per prop.
-- [ ] Add a `prop_gallery` capture to `capture_screenshots.gd` (each prop close-up on a plain
-      backdrop) and wire it to `screen_designs.py` so prop regressions show up in `compare`.
-- [ ] Verify all prop instances share their imported material (no per-instance duplication) and
-      keep a documented triangle/vertex budget in the pipeline docstring.
-- [ ] Update the README prop list and the `model_pipeline.py` catalogue docs when new props land.
+The sections below are the rest of the presentation pass: NPC characters and player movement.
+Each task is meant to be a small, reviewable slice with its own verification.
 
 ## Better NPC Characters
 

src/test/capture_prop_gallery.gd

@@ -0,0 +1,104 @@
+extends SceneTree
+## Dev helper: render every generated prop side by side on a plain backdrop and
+## save user://screenshots/10-prop-gallery.png. The image feeds
+## `tools/screen_designs.py compare` so a prop regression is visible.
+##
+## Usage: godot --path . --script res://src/test/capture_prop_gallery.gd
+
+const OUT_DIR := "user://screenshots"
+const MODEL_DIR := "res://assets/models/generated/"
+const PROPS := ["bollard", "bench", "trash_bin", "planter_box",
+	"newspaper_box", "fire_hydrant"]
+const SPACING := 1.9
+
+var frames := 0
+
+func _initialize() -> void:
+	root.size = Vector2i(1280, 720)
+	_build_stage()
+
+func _build_stage() -> void:
+	var stage := Node3D.new()
+	stage.name = "PropGallery"
+	root.add_child(stage)
+
+	var environment := Environment.new()
+	environment.background_mode = Environment.BG_COLOR
+	environment.background_color = Color(0.52, 0.54, 0.58)
+	environment.ambient_light_source = Environment.AMBIENT_SOURCE_COLOR
+	environment.ambient_light_color = Color(0.78, 0.80, 0.84)
+	environment.ambient_light_energy = 0.8
+	var world_env := WorldEnvironment.new()
+	world_env.environment = environment
+	stage.add_child(world_env)
+
+	# Floor and a plain backdrop wall: a studio line-up with no street context.
+	var floor_mesh := PlaneMesh.new()
+	floor_mesh.size = Vector2(14, 8)
+	var floor := MeshInstance3D.new()
+	floor.mesh = floor_mesh
+	floor.material_override = _flat(Color(0.50, 0.51, 0.54), 0.9)
+	stage.add_child(floor)
+
+	var backdrop_mesh := BoxMesh.new()
+	backdrop_mesh.size = Vector3(14, 6, 0.1)
+	var backdrop := MeshInstance3D.new()
+	backdrop.mesh = backdrop_mesh
+	backdrop.material_override = _flat(Color(0.55, 0.57, 0.61), 0.95)
+	backdrop.position = Vector3(0, 3.0, -3.4)
+	stage.add_child(backdrop)
+
+	# Raised back row so both rows read in a single shot.
+	var platform_mesh := BoxMesh.new()
+	platform_mesh.size = Vector3(6.8, 0.8, 1.9)
+	var platform := MeshInstance3D.new()
+	platform.mesh = platform_mesh
+	platform.material_override = _flat(Color(0.38, 0.39, 0.42), 0.85)
+	platform.position = Vector3(0, 0.4, -2.1)
+	stage.add_child(platform)
+
+	var light := DirectionalLight3D.new()
+	light.rotation_degrees = Vector3(-48, -35, 0)
+	light.light_energy = 0.85
+	light.shadow_enabled = true
+	stage.add_child(light)
+
+	var camera := Camera3D.new()
+	camera.position = Vector3(0, 2.1, 6.2)
+	camera.fov = 50.0
+	camera.look_at_from_position(camera.position, Vector3(0, 0.75, -1.0))
+	camera.current = true
+	stage.add_child(camera)
+
+	# 3 x 2 grid: three props on the front row, three on the back row.
+	var columns := [-1.95, 0.0, 1.95]
+	for index in PROPS.size():
+		var prop_name: String = PROPS[index]
+		var packed := ResourceLoader.load(MODEL_DIR + prop_name + ".glb") as PackedScene
+		if packed == null:
+			continue
+		var model := packed.instantiate() as Node3D
+		var col: int = index % 3
+		var row: int = index / 3
+		model.position = Vector3(columns[col], 0.8 if row == 1 else 0.0, -2.1 * row)
+		model.rotation_degrees.y = 14.0
+		stage.add_child(model)
+
+func _flat(color: Color, roughness: float) -> StandardMaterial3D:
+	var material := StandardMaterial3D.new()
+	material.albedo_color = color
+	material.roughness = roughness
+	return material
+
+func _process(_delta: float) -> bool:
+	frames += 1
+	if frames < 20:
+		return false
+	var dir := DirAccess.open("user://")
+	if dir == null or not dir.dir_exists("screenshots"):
+		dir.make_dir_recursive("screenshots")
+	var image := root.get_texture().get_image()
+	var err := image.save_png(OUT_DIR.path_join("10-prop-gallery.png"))
+	print("10-prop-gallery.png -> err=%d (%dx%d)" % [err, image.get_width(), image.get_height()])
+	quit(0)
+	return true

src/test/tests/test_generated_props.gd

@@ -68,6 +68,34 @@ func test_prop_scenes_share_one_atlas_material() -> bool:
 		instance.free()
 	return TestUtils.check(problems.is_empty(), "one atlas material per prop (%s)" % str(problems))
 
+func test_prop_instances_share_the_imported_material() -> bool:
+	## Instancing a prop must not duplicate its atlas material; every copy uses
+	## the same resource, so many props stay cheap to draw.
+	var problems: Array[String] = []
+	for prop in WorldBuilder.MODEL_PROPS:
+		var packed := ResourceLoader.load(MODEL_DIR + str(prop) + ".glb") as PackedScene
+		if packed == null:
+			problems.append("%s: no scene" % prop)
+			continue
+		var first := packed.instantiate()
+		var second := packed.instantiate()
+		var a := _first_material(first)
+		var b := _first_material(second)
+		if a == null or b == null:
+			problems.append("%s: missing material" % prop)
+		elif a.get_instance_id() != b.get_instance_id():
+			problems.append("%s: material is duplicated per instance" % prop)
+		first.free()
+		second.free()
+	return TestUtils.check(problems.is_empty(), "prop instances share materials (%s)" % str(problems))
+
+func _first_material(instance: Node) -> Material:
+	for node in instance.find_children("*", "MeshInstance3D", true, false):
+		var mesh: Mesh = (node as MeshInstance3D).mesh
+		if mesh != null and mesh.get_surface_count() > 0:
+			return mesh.surface_get_material(0)
+	return null
+
 func test_world_places_generated_props() -> bool:
 	var root := Node3D.new()
 	var builder := WorldBuilder.new(root)

tools/model_pipeline.py

@@ -11,7 +11,9 @@ keeps that art direction in one place:
     `generate_textures.py`) supplies the colour palette, so a model can look
     like the concept without a 3D-model API;
   * `build` writes standard glTF binary (`.glb`) files that Godot 4 imports as
-    `PackedScene`s, and `audit` checks the files are structurally valid.
+    `PackedScene`s, and `audit` checks the files are structurally valid and stay
+    inside the art budget (<= 400 triangles, <= 600 vertices per prop, no
+    degenerate triangles, UVs in the atlas, base at y ~= 0, one material).
 
 Commands (run from the repo root):
 
@@ -118,13 +120,13 @@ PROPS = [
                     "short stand, plain light grey studio background"),
         "parts": [
             {"shape": "box", "size": [0.44, 0.10, 0.38],
-             "at": [0, 0.08, 0], "role": "metal"},
+             "at": [0, 0.05, 0], "role": "metal"},
             {"shape": "box", "size": [0.42, 0.72, 0.34],
-             "at": [0, 0.49, 0], "role": "body"},
+             "at": [0, 0.46, 0], "role": "body"},
             {"shape": "box", "size": [0.34, 0.30, 0.03],
-             "at": [0, 0.60, 0.18], "role": "glass"},
+             "at": [0, 0.57, 0.18], "role": "glass"},
             {"shape": "box", "size": [0.44, 0.10, 0.36],
-             "at": [0, 0.90, 0], "role": "accent"},
+             "at": [0, 0.87, 0], "role": "accent"},
         ],
     },
     {
@@ -705,8 +707,58 @@ def build(only="", quiet=False) -> list:
 # Audit.
 # ---------------------------------------------------------------------------
 
+MAX_TRIANGLES = 400
+MAX_VERTICES = 600
+_DEGENERATE_AREA2 = 1e-9
+
+
+def _read_float_accessor(gltf: dict, binary: bytes, index: int) -> list:
+    """Decode a float SCALAR/VEC2/VEC3 accessor into a list of tuples/values."""
+    accessor = gltf["accessors"][index]
+    count = int(accessor["count"])
+    kind = accessor["type"]
+    width = {"SCALAR": 1, "VEC2": 2, "VEC3": 3, "VEC4": 4}[kind]
+    view = gltf["bufferViews"][accessor["bufferView"]]
+    offset = int(view.get("byteOffset", 0)) + int(accessor.get("byteOffset", 0))
+    stride = int(view.get("byteStride", width * 4))
+    values = []
+    for i in range(count):
+        base = offset + i * stride
+        row = struct.unpack_from("<" + "f" * width, binary, base)
+        values.append(row[0] if width == 1 else row)
+    return values
+
+
+def _read_index_accessor(gltf: dict, binary: bytes, index: int) -> list:
+    accessor = gltf["accessors"][index]
+    width = {5121: 1, 5123: 2, 5125: 4}.get(int(accessor["componentType"]), 2)
+    fmt = {1: "B", 2: "H", 4: "I"}[width]
+    view = gltf["bufferViews"][accessor["bufferView"]]
+    offset = int(view.get("byteOffset", 0)) + int(accessor.get("byteOffset", 0))
+    stride = int(view.get("byteStride", width))
+    out = []
+    for i in range(int(accessor["count"])):
+        out.append(struct.unpack_from("<" + fmt, binary,
+                                      offset + i * stride)[0])
+    return out
+
+
+def _triangle_area2(a, b, c) -> float:
+    ab = (b[0] - a[0], b[1] - a[1], b[2] - a[2])
+    ac = (c[0] - a[0], c[1] - a[1], c[2] - a[2])
+    cross = (ab[1] * ac[2] - ab[2] * ac[1],
+             ab[2] * ac[0] - ab[0] * ac[2],
+             ab[0] * ac[1] - ab[1] * ac[0])
+    return cross[0] * cross[0] + cross[1] * cross[1] + cross[2] * cross[2]
+
+
 def audit_glb(path: Path) -> dict:
-    """Check a .glb file's container, JSON chunk, and triangle count."""
+    """Check a .glb file's container, JSON chunk, and mesh contract.
+
+    The mesh must stay in the prop budget, have no degenerate triangles, keep
+    atlas UVs inside [0, 1], sit on the ground (min y ~= 0), and use exactly one
+    atlas material.
+    """
     issues = []
     if not path.is_file():
         return {"path": str(path), "ok": False,
@@ -765,6 +817,41 @@ def audit_glb(path: Path) -> dict:
     for buffer in gltf.get("buffers", []):
         if int(buffer.get("byteLength", 0)) > len(data):
             issues.append("buffer larger than the file")
+    if triangles > MAX_TRIANGLES:
+        issues.append(f"triangle budget exceeded ({triangles} > {MAX_TRIANGLES})")
+    # Decode geometry for the deeper checks. A malformed buffer view is already
+    # reported above, so skip quietly when the binary chunk is unusable.
+    try:
+        _, bin_len, _ = struct.unpack_from("<III", data, 12 + 8 + json_len)
+        binary = data[12 + 8 + json_len + 8:12 + 8 + json_len + 8 + bin_len]
+        vertices = 0
+        for mesh in gltf.get("meshes", []):
+            for primitive in mesh.get("primitives", []):
+                attributes = primitive.get("attributes", {})
+                positions = _read_float_accessor(
+                    gltf, binary, attributes["POSITION"])
+                vertices += len(positions)
+                if positions:
+                    min_y = min(p[1] for p in positions)
+                    if abs(min_y) > 0.02:
+                        issues.append(
+                            f"prop does not sit on the ground (min y {min_y:.3f})")
+                uvs = _read_float_accessor(
+                    gltf, binary, attributes["TEXCOORD_0"])
+                if any(not (0.0 <= u <= 1.0 and 0.0 <= v <= 1.0)
+                       for u, v in uvs):
+                    issues.append("atlas UV outside [0, 1]")
+                indices = _read_index_accessor(
+                    gltf, binary, primitive["indices"])
+                for tri in range(0, len(indices), 3):
+                    a, b, c = (positions[indices[tri + i]] for i in range(3))
+                    if _triangle_area2(a, b, c) < _DEGENERATE_AREA2:
+                        issues.append("degenerate triangle")
+                        break
+        if vertices > MAX_VERTICES:
+            issues.append(f"vertex budget exceeded ({vertices} > {MAX_VERTICES})")
+    except (KeyError, IndexError, ValueError, struct.error) as exc:
+        issues.append(f"unreadable geometry: {exc}")
     return {"path": str(path), "ok": not issues, "issues": issues,
             "triangles": triangles}
 

tools/screen_designs.py

@@ -495,6 +495,26 @@ SCREENS = [
             (0.02, 0.20, 0.36, 0.65, "reaction log"),
             (0.02, 0.94, 0.98, 0.99, "control hints"),
         ],
+    },    {
+        "name": "prop_gallery",
+        "kind": "scene",
+        "title": "Prop gallery",
+        "source": "tools/model_pipeline.py · docs screenshot set",
+        "ref": "10-prop-gallery.png",
+        "description": "Line-up of the six generated street-furniture props — a bollard, "
+                       "bench, trash bin, planter box, newspaper box and fire hydrant — on "
+                       "a plain studio backdrop, used as a close-range art check.",
+        "prompt": (
+            "Product line-up photograph of six low-poly 3D street-furniture props on a "
+            "plain light grey studio backdrop with a low display platform: a black steel "
+            "bollard, a wooden bench with black legs, a dark green trash bin, a white "
+            "planter box with a green hedge, a blue newspaper vending box and a red fire "
+            "hydrant. Even soft studio lighting, straight-on wide shot, muted realistic "
+            "colours, no people, no street context"),
+        "regions": [
+            (0.22, 0.14, 0.80, 0.47, "back row: planter, newspaper box, hydrant"),
+            (0.22, 0.38, 0.80, 0.68, "front row: bollard, bench, bin"),
+        ],
     },
 ]
 

tools/test_model_pipeline.py

@@ -195,6 +195,43 @@ class AuditTests(unittest.TestCase):
         self.assertFalse(result["ok"])
         self.assertTrue(result["issues"])
 
+    def test_audit_enforces_the_triangle_budget(self):
+        old = model_pipeline.MAX_TRIANGLES
+        model_pipeline.MAX_TRIANGLES = 10
+        try:
+            path = self.root / "bench.glb"
+            path.write_bytes(model_pipeline.build_glb(prop("bench")))
+            result = model_pipeline.audit_glb(path)
+        finally:
+            model_pipeline.MAX_TRIANGLES = old
+        self.assertFalse(result["ok"])
+        self.assertTrue(any("triangle budget" in issue for issue in result["issues"]),
+                        result["issues"])
+
+    def test_degenerate_triangle_helper(self):
+        self.assertEqual(
+            model_pipeline._triangle_area2((0, 0, 0), (1, 0, 0), (2, 0, 0)), 0.0)
+        self.assertGreater(
+            model_pipeline._triangle_area2((0, 0, 0), (1, 0, 0), (0, 1, 0)), 0.0)
+
+    def test_audit_reads_positions_and_uvs_from_the_binary(self):
+        parsed = parse_glb(model_pipeline.build_glb(prop("bollard")))
+        gltf, binary = parsed["gltf"], parsed["binary"]
+        primitive = gltf["meshes"][0]["primitives"][0]
+        positions = model_pipeline._read_float_accessor(
+            gltf, binary, primitive["attributes"]["POSITION"])
+        uvs = model_pipeline._read_float_accessor(
+            gltf, binary, primitive["attributes"]["TEXCOORD_0"])
+        indices = model_pipeline._read_index_accessor(
+            gltf, binary, primitive["indices"])
+        self.assertEqual(len(positions), gltf["accessors"][
+            primitive["attributes"]["POSITION"]]["count"])
+        self.assertEqual(len(uvs), len(positions))
+        self.assertEqual(len(indices) % 3, 0)
+        self.assertLess(min(p[1] for p in positions), 0.01)
+        for u, v in uvs:
+            self.assertTrue(0.0 <= u <= 1.0 and 0.0 <= v <= 1.0)
+
     def test_build_writes_into_the_models_directory(self):
         old = model_pipeline.MODELS_DIR
         model_pipeline.MODELS_DIR = self.root