Hartmut
d843162e5f
Extract Base Color, Metallic, Roughness, Transmission, IOR from Blender asset library materials via catalog_assets.py. Store in catalog JSON and serve via /api/asset-libraries/pbr-map endpoint. Frontend viewers apply PBR properties to Three.js MeshStandardMaterial using hex color strings (avoiding Three.js ColorManagement sRGB/linear issues). Key fixes: - RLS bypass for material alias lookup in pbr-map endpoint - pbrMap empty guard prevents premature grey fallback in viewers - Cache-Control: no-cache on pbr-map requests to avoid stale data Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
104 lines
3.1 KiB
Python
104 lines
3.1 KiB
Python
"""Blender headless script: extract asset catalog from a .blend library file.
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Usage:
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blender --background --python catalog_assets.py -- <blend_path>
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Outputs a single JSON line to stdout:
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{"materials": [{"name": "Mat1", "base_color": [R,G,B], "metallic": 0.0, ...}, ...],
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"node_groups": ["NG1", ...]}
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Only assets marked via Blender's asset system (asset_data is not None) are included.
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PBR properties are extracted from the Principled BSDF node of each material.
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"""
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from __future__ import annotations
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import json
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import math
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import sys
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import traceback
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def _linear_to_srgb(v: float) -> float:
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"""Convert a single linear color channel to sRGB."""
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if v <= 0.0031308:
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return v * 12.92
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return 1.055 * math.pow(v, 1.0 / 2.4) - 0.055
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def _extract_pbr(mat) -> dict:
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"""Extract PBR properties from a Blender material's Principled BSDF node.
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Returns dict with: name, base_color (sRGB), metallic, roughness, transmission, ior.
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Falls back to diffuse_color if no Principled BSDF found.
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"""
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entry = {
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"name": mat.name,
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"base_color": [0.5, 0.5, 0.5],
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"metallic": 0.0,
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"roughness": 0.5,
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"transmission": 0.0,
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"ior": 1.45,
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}
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# Find Principled BSDF node
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bsdf = None
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if mat.use_nodes and mat.node_tree:
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for node in mat.node_tree.nodes:
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if node.type == "BSDF_PRINCIPLED":
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bsdf = node
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break
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if bsdf:
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# Base Color — convert linear → sRGB
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bc = bsdf.inputs["Base Color"].default_value
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entry["base_color"] = [
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round(_linear_to_srgb(bc[0]), 4),
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round(_linear_to_srgb(bc[1]), 4),
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round(_linear_to_srgb(bc[2]), 4),
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]
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entry["metallic"] = round(bsdf.inputs["Metallic"].default_value, 4)
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entry["roughness"] = round(bsdf.inputs["Roughness"].default_value, 4)
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# Transmission Weight (Blender 4.0+) or Transmission (older)
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for tx_name in ("Transmission Weight", "Transmission"):
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if tx_name in bsdf.inputs:
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entry["transmission"] = round(bsdf.inputs[tx_name].default_value, 4)
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break
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if "IOR" in bsdf.inputs:
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entry["ior"] = round(bsdf.inputs["IOR"].default_value, 4)
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else:
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# Fallback: use viewport diffuse_color (already sRGB)
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dc = mat.diffuse_color
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entry["base_color"] = [round(dc[0], 4), round(dc[1], 4), round(dc[2], 4)]
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return entry
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def main() -> None:
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argv = sys.argv
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if "--" not in argv:
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print(json.dumps({"error": "No blend path provided after --"}))
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sys.exit(1)
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blend_path = argv[argv.index("--") + 1]
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import bpy # type: ignore[import]
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bpy.ops.wm.open_mainfile(filepath=blend_path)
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materials = [
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_extract_pbr(m) for m in bpy.data.materials if m.asset_data is not None
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]
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node_groups = [ng.name for ng in bpy.data.node_groups if ng.asset_data is not None]
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catalog = {"materials": materials, "node_groups": node_groups}
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print(json.dumps(catalog))
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try:
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main()
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except SystemExit:
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raise
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except Exception:
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traceback.print_exc()
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sys.exit(1)
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