fix particles creating an invalid node cache state (fixes #141)

export/duplis.py

@@ -97,6 +97,12 @@ def convert(exporter, blender_obj, scene, context, luxcore_scene, engine=None):
         # Need to parse so we have the dupli objects available for DuplicateObject
         luxcore_scene.Parse(dupli_props)
 
+        # We have to invalidate the node cache because we have defined materials in
+        # the dupli_props which are not defined in the main scene props (so if
+        # another material tries to use the cached name, it will result in default
+        # grey matte because the name is not in the main properties)
+        exporter.node_cache.clear()
+
         for duplis in exported_duplis.values():
             # exported_obj sometimes is None, e.g. when instancing a group using an empty
             exported_obj = duplis.exported_obj
@@ -120,16 +126,16 @@ def convert(exporter, blender_obj, scene, context, luxcore_scene, engine=None):
                     # Delete the object we used for duplication, we don't want it to show up in the scene
                     luxcore_scene.DeleteObject(src_name)
 
-
         print("Dupli export took %.3f s" % (time() - start))
     except Exception as error:
         msg = '[Duplicator "%s"] %s' % (blender_obj.name, error)
         scene.luxcore.errorlog.add_warning(msg)
         import traceback
         traceback.print_exc()
 
+
 def _get_name_suffix(name_prefix, dupli, context):
     name_suffix = name_prefix + str(dupli.index)
     if dupli.particle_system:
         name_suffix += utils.get_luxcore_name(dupli.particle_system, context)
-    return name_suffix
+    return name_suffix

tests/particles/particles.test.py

@@ -0,0 +1,113 @@
+import unittest
+import sys
+
+import BlendLuxCore
+from BlendLuxCore.bin import pyluxcore
+from BlendLuxCore.export import Exporter
+from BlendLuxCore import utils
+import bpy
+
+TEST_FRAME = 3
+TEST_SUBFRAME = 0.0
+
+
+def luxcore_logger(message):
+    # In case you need the output
+    # print(message)
+    pass
+
+
+def assertListsAlmostEqual(test_case, list1, list2, places=3):
+    test_case.assertEqual(len(list1), len(list2))
+
+    for i in range(len(list1)):
+        try:
+            test_case.assertAlmostEqual(list1[i], list2[i], places=places)
+        except AssertionError as e:
+            print()
+            print("AssertionError:", e)
+            print("Failed list index:", i)
+            print("Got list:     ", list1)
+            print("Expected list:", list2)
+            print()
+            raise
+
+
+def assertAlmostEqual(test_case, value1, value2, places=3):
+    # Try to unpack the value if it is a list with only one element (common for LuxCore props)
+    if isinstance(value1, list) and isinstance(value2, list):
+        test_case.assertEqual(len(value1), 1)
+        test_case.assertEqual(len(value1), len(value2))
+        test_case.assertAlmostEqual(value1[0], value2[0], places=places)
+    else:
+        test_case.assertAlmostEqual(value1, value2, places=places)
+
+
+def export(blender_scene):
+    # Export the scene (with silenced pyluxcore)
+    pyluxcore.Init(luxcore_logger)
+    blender_scene.luxcore.active_layer_index = 0
+    exporter = Exporter(blender_scene)
+    session = exporter.create_session()
+
+    config = session.GetRenderConfig()
+    luxcore_scene = config.GetScene()
+    scene_props = luxcore_scene.ToProperties()
+    return scene_props
+
+
+class TestParticles(unittest.TestCase):
+    def test_materials(self):
+        blender_scene = bpy.context.scene
+
+        # Export the scene
+        scene_props = export(blender_scene)
+
+        # Note: the "000" at the end of the name is there because LuxCore objects can only have
+        # one material, while Blender objects can have multiple, so one Blender object might be
+        # split into multiple LuxCore objects on export and an index is added to the name
+        particle_base_obj = bpy.data.objects["ParticleBase"]
+        particle_base_obj_name = utils.get_luxcore_name(particle_base_obj, is_viewport_render=False) + "000"
+        particle_base_mat = particle_base_obj.material_slots[0].material
+        particle_base_mat_name = utils.get_luxcore_name(particle_base_mat, is_viewport_render=False)
+
+        emitter_obj = bpy.data.objects["Emitter"]
+        emitter_obj_name = utils.get_luxcore_name(emitter_obj, is_viewport_render=False) + "000"
+        emitter_mat = emitter_obj.material_slots[0].material
+        emitter_mat_name = utils.get_luxcore_name(emitter_mat, is_viewport_render=False)
+
+        # Check properties for correctness
+        all_exported_obj_prefixes = scene_props.GetAllUniqueSubNames("scene.objects")
+
+        for prefix in all_exported_obj_prefixes:
+            luxcore_name = prefix.split(".")[-1]
+
+            if luxcore_name == particle_base_obj_name:
+                self.assertEqual(scene_props.Get(prefix + ".material").GetString(), particle_base_mat_name)
+                mat_prefix = "scene.materials." + particle_base_mat_name
+                # LuxCore inserts an implicit property texture here (probably because we use DuplicateObject)
+                kd_tex_name = scene_props.Get(mat_prefix + ".kd").GetString()
+                kd_tex_prefix = "scene.textures." + kd_tex_name
+                assertListsAlmostEqual(self, scene_props.Get(kd_tex_prefix + ".value").GetFloats(), [0.7, 0.0, 0.0])
+            elif luxcore_name == emitter_obj_name:
+                self.assertEqual(scene_props.Get(prefix + ".material").GetString(), emitter_mat_name)
+                mat_prefix = "scene.materials." + emitter_mat_name
+                # LuxCore inserts an implicit property texture here (probably because we use DuplicateObject)
+                kd_tex_name = scene_props.Get(mat_prefix + ".kd").GetString()
+                kd_tex_prefix = "scene.textures." + kd_tex_name
+                assertListsAlmostEqual(self, scene_props.Get(kd_tex_prefix + ".value").GetFloats(), [0.0, 0.7, 0.0])
+            else:
+                # It is one of the instanced particles
+                self.assertEqual(scene_props.Get(prefix + ".material").GetString(), particle_base_mat_name)
+                mat_prefix = "scene.materials." + particle_base_mat_name
+                # LuxCore inserts an implicit property texture here (probably because we use DuplicateObject)
+                kd_tex_name = scene_props.Get(mat_prefix + ".kd").GetString()
+                kd_tex_prefix = "scene.textures." + kd_tex_name
+                assertListsAlmostEqual(self, scene_props.Get(kd_tex_prefix + ".value").GetFloats(), [0.7, 0.0, 0.0])
+
+
+# we have to manually invoke the test runner here, as we cannot use the CLI
+suite = unittest.defaultTestLoader.loadTestsFromTestCase(TestParticles)
+result = unittest.TextTestRunner().run(suite)
+
+sys.exit(not result.wasSuccessful())