fix: 将线稿渲染背景从白色改为黑色

修复线稿渲染背景颜色错误的问题，将原本的白色背景和材质改为黑色，以生成正确的黑白线稿图。同时更新了相关的材质、世界环境和清理函数中的临时资源名称。

utils.py

@@ -321,9 +321,9 @@ def _render_normal(operator):
     return _render_with_material(operator, normal_mat, 'normal.png', '法向')
 
 
-def _create_white_material():
-    """Create a flat white emission material for line art background."""
-    mat_name = '__ComfyWhiteMat__'
+def _create_black_material():
+    """Create a flat black emission material for line art background."""
+    mat_name = '__ComfyBlackMat__'
     if mat_name in bpy.data.materials:
         return bpy.data.materials[mat_name]
 
@@ -335,7 +335,7 @@ def _create_white_material():
 
     emission = nodes.new('ShaderNodeEmission')
     emission.location = (0, 0)
-    emission.inputs['Color'].default_value = (1, 1, 1, 1)
+    emission.inputs['Color'].default_value = (0, 0, 0, 1)
     emission.inputs['Strength'].default_value = 1.0
 
     output = nodes.new('ShaderNodeOutputMaterial')
@@ -369,7 +369,7 @@ def _render_lineart(operator):
     orig_world = scene.world
 
     # Apply white emission material to all slots
-    white_mat = _create_white_material()
+    white_mat = _create_black_material()
     if len(converted_obj.material_slots) == 0:
         converted_obj.data.materials.append(white_mat)
     else:
@@ -381,7 +381,7 @@ def _render_lineart(operator):
     vl.use_freestyle = True
     scene.render.line_thickness = 1.0
 
-    # Configure lineset: black lines, all relevant edge types
+    # Configure lineset: white lines, all relevant edge types
     fs = vl.freestyle_settings
     # Save original linesets state
     orig_lineset_settings = []
@@ -396,21 +396,25 @@ def _render_lineart(operator):
     else:
         ls = fs.linesets[0]
 
-    ls.linestyle.color = (0, 0, 0)  # Black lines
+    ls.linestyle.color = (1, 1, 1)
     ls.linestyle.thickness = 1.5
     ls.select_silhouette = True
     ls.select_border = True
     ls.select_crease = True
     ls.select_edge_mark = True
 
-    # White world background
-    white_world = bpy.data.worlds.new('__ComfyWhiteWorld__')
-    white_world.use_nodes = True
-    bg_node = white_world.node_tree.nodes.get('Background')
-    if bg_node:
-        bg_node.inputs['Color'].default_value = (1, 1, 1, 1)
-        bg_node.inputs['Strength'].default_value = 1.0
-    scene.world = white_world
+    black_world = bpy.data.worlds.new('__ComfyBlackWorld__')
+    black_world.use_nodes = True
+    wn = black_world.node_tree
+    wn.nodes.clear()
+    bg_node = wn.nodes.new('ShaderNodeBackground')
+    bg_node.location = (0, 0)
+    bg_node.inputs['Color'].default_value = (0, 0, 0, 1)
+    bg_node.inputs['Strength'].default_value = 1.0
+    output_node = wn.nodes.new('ShaderNodeOutputWorld')
+    output_node.location = (200, 0)
+    wn.links.new(bg_node.outputs['Background'], output_node.inputs['Surface'])
+    scene.world = black_world
     scene.render.film_transparent = False
 
     # Disable compositor
@@ -453,8 +457,8 @@ def _render_lineart(operator):
     scene.world = orig_world
 
     # Remove temporary world
-    if '__ComfyWhiteWorld__' in bpy.data.worlds:
-        bpy.data.worlds.remove(bpy.data.worlds['__ComfyWhiteWorld__'])
+    if '__ComfyBlackWorld__' in bpy.data.worlds:
+        bpy.data.worlds.remove(bpy.data.worlds['__ComfyBlackWorld__'])
 
     _add_rendered_image(scene, '线稿', out_path)
     return True
@@ -614,7 +618,7 @@ class Comfy_OT_CleanupMvgen(bpy.types.Operator):
         pcoll.clear()
 
         # Remove temp materials
-        for mat_name in ('__ComfyDepthMat__', '__ComfyWhiteMat__'):
+        for mat_name in ('__ComfyDepthMat__', '__ComfyBlackMat__'):
             if mat_name in bpy.data.materials:
                 bpy.data.materials.remove(bpy.data.materials[mat_name])