New unit tests for collision detection api (#173)

* New unit tests for collision detection api

* Added drawings of collision types to unit tests

* Clockwise region used for collision detection

* Fix for failing tests, added equivalency for entities independent of list index and direction

* Review updates

---------

Co-authored-by: JackDavies <[email protected]>

doc/source/methods/geometry_functions.rst

@@ -10,6 +10,8 @@ Geometry Objects
    :toctree: _autosummary_geometry_methods
 
    Region
+   Coordinate
+   Entity
    Line
    Arc
 
@@ -18,5 +20,8 @@ Geometry Functions
 .. autosummary::
    :toctree: _autosummary_geometry_functions
 
+   get_entities_have_common_coordinate
+   entities_same
+   reverse_entities
    xy_to_rt
    rt_to_xy

src/ansys/motorcad/core/geometry.py

@@ -27,10 +27,15 @@ def __eq__(self, other):
             and self.colour == other.colour
             # and self.area == other.area ->
             # Already check entities - can't expect user to calculate area
-            and self.centroid == other.centroid
-            and self.region_coordinate == other.region_coordinate
+            # and self.centroid == other.centroid ->
+            # Centroid calculated from entities - can't expect user to calculate
+            # and self.region_coordinate == other.region_coordinate ->
+            # Region coordinate is an output, cannot guarantee will be same for identical regions
             and self.duplications == other.duplications
-            and self.entities == other.entities
+            and (
+                entities_same(self.entities, other.entities, check_reverse=False)
+                or entities_same(self.entities, other.entities, check_reverse=True)
+            )
         ):
             return True
         else:
@@ -207,6 +212,10 @@ def __eq__(self, other):
         else:
             return False
 
+    def reverse(self):
+        """Reverse Entity class."""
+        return Entity(self.end, self.start)
+
 
 class Line(Entity):
     """Python representation of Motor-CAD line entity based upon start and end coordinates.
@@ -301,6 +310,10 @@ def get_length(self):
         """
         return sqrt(pow(self.start.x - self.end.x, 2) + pow(self.start.y - self.end.y, 2))
 
+    def reverse(self):
+        """Reverse Line entity."""
+        return Line(self.end, self.start)
+
 
 class Arc(Entity):
     """Python representation of Motor-CAD arc entity based upon start, end, centre and radius.
@@ -414,6 +427,10 @@ def get_length(self):
 
         return self.radius * radians(arc_angle)
 
+    def reverse(self):
+        """Reverse Arc entity."""
+        return Arc(self.end, self.start, self.centre, -self.radius)
+
 
 def _convert_entities_to_json(entities):
     """Get entities list as a json object.
@@ -516,6 +533,63 @@ def get_entities_have_common_coordinate(entity_1, entity_2):
         return False
 
 
+def entities_same(entities_a, entities_b, check_reverse=False):
+    """Check whether entities in region are the same as entities a different region.
+
+    Parameters
+    ----------
+    entities_a : list of Line or list of Arc
+        list of Line and Arc objects.
+
+    entities_b : list of Line or list of Arc
+        list of Line and Arc objects.
+
+    check_reverse : Boolean
+        Whether to reverse entities when checking entity equivalency.
+
+    Returns
+    ----------
+    boolean
+    """
+    if check_reverse:
+        entities_b = reverse_entities(entities_b)
+
+    start_index = 0
+
+    for count, entity in enumerate(entities_b):
+        if entity == entities_a[0]:
+            # start entity found
+            start_index = count
+            break
+
+    # regenerate entities_b from start index found from entities_a
+    entities = [entities_b[i] for i in range(start_index, len(entities_a))] + [
+        entities_b[i] for i in range(0, start_index)
+    ]
+
+    if entities == entities_a:
+        return True
+    else:
+        return False
+
+
+def reverse_entities(entities):
+    """Reverse list of line/arc entities, including entity start end coordinates.
+
+    Parameters
+    ----------
+    entities : list of Line or list of Arc
+        list of Line and Arc objects.
+
+    Returns
+    ----------
+    list of Line or list of Arc
+        list of Line and Arc objects.
+    """
+    entities.reverse()
+    return [entity.reverse() for entity in entities]
+
+
 def xy_to_rt(x, y):
     """Convert Motor-CAD Cartesian coordinates to polar coordinates in degrees.
 

tests/test_geometry.py

@@ -20,10 +20,10 @@ def generate_constant_region():
     region.entities.append(geometry.Line(geometry.Coordinate(-1, 0), geometry.Coordinate(1, 0)))
     region.entities.append(
         geometry.Arc(
-            geometry.Coordinate(1, 0), geometry.Coordinate(1, 1), geometry.Coordinate(0, 0), 1
+            geometry.Coordinate(1, 0), geometry.Coordinate(0, 1), geometry.Coordinate(0, 0), 1
         )
     )
-    region.entities.append(geometry.Line(geometry.Coordinate(1, 1), geometry.Coordinate(-1, 0)))
+    region.entities.append(geometry.Line(geometry.Coordinate(0, 1), geometry.Coordinate(-1, 0)))
 
     return region
 
@@ -302,6 +302,73 @@ def test_region_is_closed():
     assert region.is_closed()
 
 
+def test_region_contains_same_entities():
+    region = generate_constant_region()
+
+    expected_region = region
+    expected_region.entities = geometry.reverse_entities(region.entities)
+
+    assert region == expected_region
+
+
+def test_reverse_entity():
+    entity = geometry.Entity(geometry.Coordinate(0, 0), geometry.Coordinate(1, 1))
+    expected_entity = geometry.Entity(geometry.Coordinate(1, 1), geometry.Coordinate(0, 0))
+
+    assert entity.reverse() == expected_entity
+
+
+def test_reverse_line():
+    region = generate_constant_region()
+    line = region.entities[0]
+    expected_line = geometry.Line(line.end, line.start)
+
+    assert line.reverse() == expected_line
+
+
+def test_reverse_arc():
+    region = generate_constant_region()
+    arc = region.entities[1]
+    expected_line = geometry.Arc(arc.end, arc.start, arc.centre, -arc.radius)
+
+    assert arc.reverse() == expected_line
+
+
+def test_entities_same():
+    region = generate_constant_region()
+    region_expected = generate_constant_region()
+
+    assert geometry.entities_same(region.entities, region_expected.entities)
+
+
+def test_entities_same_1():
+    region = generate_constant_region()
+
+    entities = [region.entities[i] for i in range(1, len(region.entities))] + [
+        region.entities[i] for i in range(0, 1)
+    ]
+
+    assert geometry.entities_same(region.entities, entities)
+
+
+def test_reverse_entities():
+    region = generate_constant_region()
+
+    expected_entities = []
+
+    for entity in region.entities:
+        if isinstance(entity, geometry.Line):
+            expected_entities.append(geometry.Line(entity.end, entity.start))
+        elif isinstance(entity, geometry.Arc):
+            expected_entities.append(
+                geometry.Arc(entity.end, entity.start, entity.centre, -entity.radius)
+            )
+
+    expected_entities.reverse()
+
+    assert geometry.reverse_entities(region.entities) == expected_entities
+
+
 def test_line_get_coordinate_from_percentage_distance():
     line = geometry.Line(geometry.Coordinate(0, 0), geometry.Coordinate(2, 0))
 
@@ -541,3 +608,144 @@ def test_unite_regions_2():
     union = mc.unite_regions(square, [triangle])
 
     assert expected_region == union
+
+
+def test_check_collisions():
+    """Collision Type : Collision detected.
+    No vertices from the other region within the other region."""
+    #      Before                          After
+    #
+    #      |---|
+    #      |   |
+    #   |--|---|--|
+    #   |  |   |  |     ->      Collision detected between regions
+    #   |  |   |  |
+    #   |--|---|--|
+    #      |   |
+    #      |---|
+    #
+    region_a = generate_constant_region()
+
+    region_b = geometry.Region()
+    region_b.add_entity(geometry.Line(geometry.Coordinate(0, -2), geometry.Coordinate(1, 2)))
+    region_b.add_entity(geometry.Line(geometry.Coordinate(1, 2), geometry.Coordinate(5, -3)))
+    region_b.add_entity(geometry.Line(geometry.Coordinate(5, -3), geometry.Coordinate(0, -2)))
+
+    collisions = mc.check_collisions(region_a, [region_b, mc.get_region("Stator")])
+    num_collisions = len(collisions)
+
+    assert num_collisions == 1
+    assert collisions[0] == region_b
+
+
+def test_check_collisions_1():
+    """Collision Type : Collision Detected.
+    Two vertices from the other region within the other region."""
+    #      Before                          After
+    #
+    #   |---------|
+    #   |         |     ->      Collision detected between regions
+    #   |  |---|  |
+    #   |--|---|--|
+    #      |   |
+    #      |---|
+    #
+    region_a = generate_constant_region()
+
+    region_b = geometry.Region()
+    region_b.add_entity(
+        geometry.Line(geometry.Coordinate(-0.2, -2), geometry.Coordinate(-0.2, 0.2))
+    )
+    region_b.add_entity(
+        geometry.Line(geometry.Coordinate(-0.2, 0.2), geometry.Coordinate(0.2, 0.2))
+    )
+    region_b.add_entity(geometry.Line(geometry.Coordinate(0.2, 0.2), geometry.Coordinate(0.2, -2)))
+    region_b.add_entity(geometry.Line(geometry.Coordinate(0.2, -2), geometry.Coordinate(-0.2, -2)))
+
+    collisions = mc.check_collisions(region_a, [region_b, mc.get_region("Stator")])
+    num_collisions = len(collisions)
+
+    assert num_collisions == 1
+    assert collisions[0] == region_b
+
+
+def test_check_collisions_2():
+    """Collision Type : No collision.
+    Regions touching on single entity"""
+    #      Before                          After
+    #
+    #   |---------|
+    #   |         |     ->      No collision detected between regions
+    #   |         |
+    #   |--|---|--|
+    #      |   |
+    #      |---|
+    #
+    region_a = generate_constant_region()
+
+    region_b = geometry.Region()
+    region_b.add_entity(geometry.Line(geometry.Coordinate(-0.2, -2), geometry.Coordinate(-0.2, 0)))
+    region_b.add_entity(geometry.Line(geometry.Coordinate(-0.2, 0), geometry.Coordinate(0.2, 0)))
+    region_b.add_entity(geometry.Line(geometry.Coordinate(0.2, 0), geometry.Coordinate(0.2, -2)))
+    region_b.add_entity(geometry.Line(geometry.Coordinate(0.2, -2), geometry.Coordinate(-0.2, -2)))
+
+    collisions = mc.check_collisions(region_a, [region_b, mc.get_region("Stator")])
+    num_collisions = len(collisions)
+
+    assert num_collisions == 0
+
+
+def test_check_collisions_3():
+    """Collision Type : Collision detected.
+    No vertices from the other region within the other region.
+    Square region drawn clockwise."""
+    #      Before                          After
+    #
+    #      |---|
+    #      |   |
+    #   |--|---|--|
+    #   |  |   |  |     ->      Collision detected between regions
+    #   |  |   |  |
+    #   |--|---|--|
+    #      |   |
+    #      |---|
+    #
+    s_p = []
+    s_l = []
+
+    s_p.append(geometry.Coordinate(0, 0))
+    s_p.append(geometry.Coordinate(0, 2))
+    s_p.append(geometry.Coordinate(2, 2))
+    s_p.append(geometry.Coordinate(2, 0))
+
+    s_l.append(geometry.Line(s_p[0], s_p[1]))
+    s_l.append(geometry.Line(s_p[1], s_p[2]))
+    s_l.append(geometry.Line(s_p[2], s_p[3]))
+    s_l.append(geometry.Line(s_p[3], s_p[0]))
+
+    square = geometry.Region()
+    for entity in s_l:
+        square.add_entity(entity)
+
+    t_p = []
+    t_l = []
+
+    t_p.append(geometry.Coordinate(1, 2.2))
+    t_p.append(geometry.Coordinate(2.2, 1))
+    t_p.append(geometry.Coordinate(4, 4))
+
+    t_l.append(geometry.Line(t_p[0], t_p[1]))
+    t_l.append(geometry.Line(t_p[1], t_p[2]))
+    t_l.append(geometry.Line(t_p[2], t_p[0]))
+
+    triangle = geometry.Region()
+    for entity in t_l:
+        triangle.add_entity(entity)
+
+    collisions = mc.check_collisions(triangle, [square])
+    assert len(collisions) == 1
+    assert collisions[0] == square
+
+    collisions = mc.check_collisions(square, [triangle])
+    assert len(collisions) == 1
+    assert collisions[0] == triangle