update Collada Importer: reworked export and import of Materials

- added import of transparency and emission into principled BSDF Shader
- added support for importing all default collada material parameters

  * diffuse
  * emission
  * index_of_refraction
  * shininess (mapped to BSDF Roughness)
  * reflectivity (mapped to BSDF Metallic)
  * transparency + transparent mapped to BSDF Alpha)
  * ambient (creates unconnected texture node)
  * specular (creates unconnected texture node)
  * reflective(creates unconnected texture node)

- added support for exporting collada material parameters:

  * diffuse
  * emission
  * index_of_refraction
  * shininess (mapped to BSDF Roughness)
  * reflectivity (mapped to BSDF Metallic)
  * transparency + transparent mapped to BSDF Alpha)

- prepared support for exporting the following parameters
  but currently commented out:

  * ambient (creates unconnected texture node)
  * specular (creates unconnected texture node)
  * reflective(creates unconnected texture node)

  Problem: For now we only allow export of principled BSDF based
  materials. I am not sure from where to get ambient, specular
  and reflective as those values are not included in the
  principled BSDF Shader (wip).

1 files changed, 15 insertions, 8 deletions

diff --git a/source/blender/collada/DocumentImporter.cpp b/source/blender/collada/DocumentImporter.cpp
index 1c241671c81..06f6682f401 100644
--- a/source/blender/collada/DocumentImporter.cpp
+++ b/source/blender/collada/DocumentImporter.cpp
@@ -796,14 +796,21 @@ bool DocumentImporter::writeMaterial(const COLLADAFW::Material *cmat)
 void DocumentImporter::write_profile_COMMON(COLLADAFW::EffectCommon *ef, Material *ma)
 {
   MaterialNode matNode = MaterialNode(mContext, ef, ma, uid_image_map);
-  matNode.set_reflectivity(ef->getReflectivity().getFloatValue());
-  matNode.set_ior(ef->getIndexOfRefraction().getFloatValue());
-  matNode.set_diffuse(ef->getDiffuse(), "Diffuse");
-  matNode.set_ambient(ef->getAmbient(), "Ambient");
-  matNode.set_specular(ef->getSpecular(), "Specular");
-  matNode.set_reflective(ef->getReflective(), "Reflective");
-  matNode.set_emission(ef->getEmission(), "Emission");
-  matNode.set_opacity(ef->getOpacity(), "Opacity");
+
+  /* Direct mapping to principled BSDF Shader */
+  matNode.set_diffuse(ef->getDiffuse());
+  matNode.set_emission(ef->getEmission());
+  matNode.set_ior(ef->getIndexOfRefraction());
+  matNode.set_alpha(ef->getOpaqueMode(), ef->getTransparent(), ef->getTransparency());
+
+  /* following mapping still needs to be verified */
+  matNode.set_shininess(ef->getShininess());
+  matNode.set_reflectivity(ef->getReflectivity());
+
+  /* not supported by principled BSDF */
+  matNode.set_ambient(ef->getAmbient());
+  matNode.set_specular(ef->getSpecular());
+  matNode.set_reflective(ef->getReflective());
 }
 
 /** When this method is called, the writer must write the effect.