feat: Add BEN2 background removal functionality and integrate into SnapForm

- Introduced BEN2 model for background removal in the panel and properties.
- Updated runtime to handle background removal commands and model downloads.
- Implemented background removal logic in worker, including image processing and saving results.
- Enhanced tests to cover new background removal features and ensure proper integration.
- Updated version to 0.9.28 to reflect new features and improvements.

tests/test_image_depth.py

@@ -298,9 +298,52 @@ class ImageDepthTest(unittest.TestCase):
         original_source = inspect.getsource(
             self.image_depth.build_image_depth_plane
         )
-        self.assertIn("depth_name = depth_data_name(source_object)", estimate_source)
+        self.assertIn(
+            "depth_name = depth_name or depth_data_name(source_object)",
+            estimate_source,
+        )
         self.assertIn("depth_data_name(source_object)", original_source)
 
+    def test_removed_background_name_uses_source_image_base_name(self):
+        source_object = SimpleNamespace(
+            data=SimpleNamespace(name="img.png"),
+        )
+
+        self.assertEqual(
+            self.image_depth.removed_background_data_name(source_object),
+            "img.rb",
+        )
+        source_object.data.name = "img.png.001"
+        self.assertEqual(
+            self.image_depth.removed_background_data_name(source_object),
+            "img.001.rb",
+        )
+
+    def test_depth_name_override_keeps_original_base_name(self):
+        source = inspect.getsource(self.image_depth.build_depth_plane)
+
+        self.assertIn(
+            "depth_name = depth_name or depth_data_name(source_object)",
+            source,
+        )
+        self.assertIn(
+            "color_image if color_image is not None else source_object.data",
+            source,
+        )
+
+    def test_original_depth_background_only_changes_material_color(self):
+        source = inspect.getsource(self.image_depth.build_image_depth_plane)
+
+        self.assertIn("texture.image = source_object.data", source)
+        self.assertIn(
+            "source_object.data if displacement_via == \"MATERIAL\" else None",
+            source,
+        )
+        self.assertIn(
+            "color_image if color_image is not None else source_object.data",
+            source,
+        )
+
     def test_material_uses_source_object_name(self):
         da3_source = inspect.getsource(self.image_depth.build_depth_plane)
         image_source = inspect.getsource(
@@ -319,7 +362,10 @@ class ImageDepthTest(unittest.TestCase):
             self.image_depth.build_depth_plane
         )
 
-        self.assertIn("depth_name = depth_data_name(source_object)", source)
+        self.assertIn(
+            "depth_name = depth_name or depth_data_name(source_object)",
+            source,
+        )
         self.assertIn("create_depth_image(\n        depth_name,", source)
         self.assertIn("bpy.data.textures.new(\n            depth_name,", source)
         self.assertIn('texture.extension = "EXTEND"', source)
@@ -385,6 +431,42 @@ class ImageDepthTest(unittest.TestCase):
         )
         self.assertIn("set_displacement_only(material)", source)
 
+    def test_unshaded_material_uses_alpha_mixed_emission(self):
+        source = inspect.getsource(self.image_depth.create_material)
+
+        unshaded_start = source.index("if unshaded:")
+        shaded_start = source.index("else:", unshaded_start)
+        displacement_start = source.index(
+            "if displacement_image is not None:",
+            shaded_start,
+        )
+        unshaded_source = source[unshaded_start:shaded_start]
+        shaded_source = source[shaded_start:displacement_start]
+
+        self.assertIn('nodes.new("ShaderNodeEmission")', unshaded_source)
+        self.assertIn(
+            'nodes.new("ShaderNodeBsdfTransparent")',
+            unshaded_source,
+        )
+        self.assertIn('nodes.new("ShaderNodeMixShader")', unshaded_source)
+        self.assertIn(
+            'color_texture.outputs["Color"]',
+            unshaded_source,
+        )
+        self.assertIn('emission.inputs["Color"]', unshaded_source)
+        self.assertIn('color_texture.outputs["Alpha"]', unshaded_source)
+        self.assertIn('mix_shader.inputs["Fac"]', unshaded_source)
+        self.assertIn('transparent.outputs["BSDF"]', unshaded_source)
+        self.assertIn('mix_shader.inputs[1]', unshaded_source)
+        self.assertIn('emission.outputs["Emission"]', unshaded_source)
+        self.assertIn('mix_shader.inputs[2]', unshaded_source)
+        self.assertIn('mix_shader.outputs["Shader"]', unshaded_source)
+        self.assertNotIn("ShaderNodeBsdfPrincipled", unshaded_source)
+        self.assertNotIn("ShaderNodeBump", unshaded_source)
+        self.assertNotIn("ShaderNodeFloatCurve", unshaded_source)
+        self.assertIn("ShaderNodeBsdfPrincipled", shaded_source)
+        self.assertGreater(displacement_start, unshaded_start)
+
     def test_displacement_values_follow_depth_source(self):
         estimate_source = inspect.getsource(
             self.image_depth.build_depth_plane
@@ -434,6 +516,7 @@ class ImageDepthTest(unittest.TestCase):
                 'if displacement_via == "MATERIAL" else None',
                 source,
             )
+            self.assertIn("unshaded=unshaded", source)
 
     def test_surface_displacement_is_set_to_displacement_only(self):
         class Material: