basic working version

addons/io_scene_swbf_msh/msh_model_utilities.py

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+""" Utilities for operating on msh_model objects. """
+
+from typing import List
+from .msh_model import *
+from .msh_utilities import *
+from mathutils import Vector, Matrix
+
+def scale_segments(scale: Vector, segments: List[GeometrySegment]):
+    """ Scales are positions in the GeometrySegment list. """
+
+    for segment in segments:
+        for pos in segment.positions:
+            pos = mul_vec(pos, scale)
+
+def get_model_world_matrix(model: Model, models: List[Model]) -> Matrix:
+    """ Gets a Blender Matrix for transforming the model into world space. """
+
+    transform_stack: List[ModelTransform] = [model.transform]
+    transform_stack.extend((parent.transform for parent in get_model_ancestors(model, models)))
+
+    world_matrix: Matrix = Matrix()
+
+    for transform in reversed(transform_stack):
+        translation_matrix = Matrix.Translation(transform.translation)
+        rotation_matrix = transform.rotation.to_matrix().to_4x4()
+
+        world_matrix = world_matrix @ (translation_matrix @ rotation_matrix)
+
+    return world_matrix
+
+def sort_by_parent(models: List[Model]) -> List[Model]:
+    """ Sorts a Model list so that models are ordered by their parent.
+        Required for some tools to be able to load .msh files. """
+
+    sorted_models: List[Model] = []
+
+    for root in get_root_models(models):
+        def add_children(model: Model):
+            nonlocal sorted_models
+
+            for child in get_model_children(model, models):
+                sorted_models.append(child)
+                add_children(child)
+
+        sorted_models.append(root)
+        add_children(root)
+
+    return sorted_models
+
+def reparent_model_roots(models: List[Model]) -> List[Model]:
+    """ Reparents all root models in a list to a new empty node. """
+
+    new_root: Model = Model()
+    new_root.name = get_unique_scene_root_name(models)
+
+    for model in models:
+        if not model.parent:
+            model.parent = new_root.name
+
+    models.insert(0, new_root)
+
+    return models
+
+def has_multiple_root_models(models: List[Model]) -> bool:
+    """ Checks if a list of Model objects has multiple roots. """
+
+    return sum(1 for root in get_root_models(models)) > 1
+
+def get_root_models(models: List[Model]) -> Model:
+    """ Generator. Returns all Model objects in a list with no parent. """
+
+    for model in models:
+        if model.parent == "":
+            yield model
+
+def get_model_children(parent: Model, models: List[Model]) -> Model:
+    """ Generator. Returns all Model objects in a list whose parent is
+        the supplied model. """
+
+    for model in models:
+        if parent.name == model.parent:
+            yield model
+
+def get_model_ancestors(child: Model, models: List[Model]) -> Model:
+    """ Generator. Yields the parent for a model, then yields the parent's parent,
+        repeating until at the root model. """
+
+    for model in models:
+        if child.parent == model.name:
+            child = model
+            yield model
+
+def get_unique_scene_root_name(models: List[Model]) -> Model:
+    """ Returns a unique model name of the form of either "SceneRoot" or
+        "SceneRoot{i}". """
+
+    name: str = "SceneRoot"
+
+    if is_model_name_unused(name, models):
+        return name
+
+    for i in range(len(models) + 1):
+        name = f"SceneRoot{i}"
+
+        if is_model_name_unused(name, models):
+            return name
+
+    return name
+
+def is_model_name_unused(name: str, models: List[Model]) -> bool:
+    """ Checks if there is no Model using a name in a list of models.  """
+
+    for model in models:
+        if model.name == name:
+            return False
+
+    return True