Update importer

• Scene & Global Transforms:

  • Cleared all nori_ custom properties from the scene on import.
  • Parsed <integrator> and <sampler> properties, storing them as nori_ scene custom properties.
  • Improved scene orientation adjustment

• Camera & Clipping:

  • Added warning for non-"area" emitter types.
  • Prioritized XML-defined nearClip and farClip for camera clipping over automatic calculation.
  • Ensured the imported camera is set as the active scene camera.

• Materials & BSDFs:

  • Refactored _create_blender_material for a streamlined node setup.
  • Emitters: Integrated radiance into the Principled BSDF (if applicable) or combined with an Emission shader via Add Shader for other BSDF types.
  • Properties: Enhanced parsing to distinguish between known BSDF properties (albedo, kd, intIOR, extIOR, alpha, diffuseStrength, specularStrength, exponent) and unknown ones (stored as nori_ material custom properties).
  • Added nori_type custom property to materials to reflect the BSDF type.
  • Microfacet: Used alpha_to_roughness conversion for Roughness input.
  • Diffuse: Explicitly set up as Principled BSDF with IOR 1.0.
  • Phong: Added support for <bsdf type="phong"> by instantiating the phong node group and mapping XML properties (albedo to kd, diffuseStrength to pd, specularStrength to ps, exponent to n).

Ich weiß nicht genau wie die Phong parameter zu verstehen sind :/