TriVoxel: Burley + (EON, Gotanda, Chan) Diffuse Models

leenkx/blender/lnx/props_renderpath.py

@@ -486,6 +486,14 @@ class LnxRPListItem(bpy.types.PropertyGroup):
                ('Solid', 'Solid', 'Solid'),
                ],
         name="Materials", description="Material builder", default='Full', update=update_material_model)
+    lnx_diffuse_model: EnumProperty(
+        items=[('Lambert', 'Lambert', 'Lambert'),
+               ('Burley', 'Burley', 'Burley with Frostbite energy renormalization'),
+               ('EON', 'Oren-Nayar', 'Energy preserving Oren Nayar with multi scatter compensation'),
+               ('Gotanda', 'Gotanda GGX Diffuse', 'Microfacet GGX diffuse with Fresnel and visibility'),
+               ('Chan', 'Chan Retroreflective', 'GGX microfacet diffuse with retroreflective lobe'),
+               ],
+        name="Diffuse BRDF", description="Diffuse BRDF model", default='Burley', update=update_material_model)
     lnx_rp_displacement: EnumProperty(
         items=[('Off', 'Off', 'Off'),
                ('Vertex', 'Vertex', 'Vertex'),