Initial release

scripts/glb_atlas.py

@@ -0,0 +1,38 @@
+#!/usr/bin/env python3
+"""Dump a GLB's baseColor + metallicRoughness atlas images side by side, so the
+bake's colour fidelity can be eyeballed without any renderer in the way.
+
+    python3 scripts/glb_atlas.py in.glb [out.png]
+"""
+import sys, numpy as np, trimesh
+from PIL import Image
+
+path = sys.argv[1]; out = sys.argv[2] if len(sys.argv) > 2 else "glb_atlas.png"
+scene = trimesh.load(path, process=False)
+mesh = scene if isinstance(scene, trimesh.Trimesh) else list(scene.geometry.values())[0]
+attrs = getattr(mesh.visual, "vertex_attributes", {})
+if "color" in attrs:
+    color = np.asarray(attrs["color"])
+    print(f"vertex-colour GLB: {len(color):,} COLOR_0 values ({color.dtype}); no UV atlas")
+    sys.exit(0)
+mat = mesh.visual.material
+bc = mat.baseColorTexture.convert("RGB")
+try:
+    mr = mat.metallicRoughnessTexture.convert("RGB")
+except Exception:
+    mr = Image.new("RGB", bc.size)
+W, H = bc.size
+# downscale for a quick look if huge
+scale = 1024 / max(W, H)
+if scale < 1:
+    bc = bc.resize((int(W*scale), int(H*scale)))
+    mr = mr.resize((int(W*scale), int(H*scale)))
+w, h = bc.size
+canvas = Image.new("RGB", (w*2 + 16, h), (30, 30, 30))
+canvas.paste(bc, (0, 0)); canvas.paste(mr, (w + 16, 0))
+canvas.save(out)
+a = np.asarray(bc, np.float64) / 255
+nz = a.reshape(-1, 3); nz = nz[nz.sum(1) > 0.05]
+print(f"atlas {W}x{H}  baseColor mean(nonblack)={nz.mean(0).round(3) if len(nz) else 'n/a'}  "
+      f"filled={len(nz)/(w*h)*100:.0f}%", flush=True)
+print("wrote", out, flush=True)