use own code for checking if polygons intersect (as opposed to finding the intersection)

snarled/main.py

@@ -11,7 +11,7 @@ from numpy.typing import NDArray, ArrayLike
 from pyclipper import scale_to_clipper, scale_from_clipper, PyPolyNode
 
 from .types import connectivity_t, layer_t, contour_t
-from .poly import poly_contains_points
+from .poly import poly_contains_points, intersects
 from .clipper import union_nonzero, union_evenodd, intersection_evenodd, difference_evenodd, hier2oriented
 from .tracker import NetsInfo, NetName
 from .utils import connectivity2layers
@@ -112,6 +112,7 @@ def trace_connectivity(
     nets_info = NetsInfo()
 
     for ii, (top_layer, via_layer, bot_layer) in enumerate(connectivity):
+        logger.info(f'{ii}, {top_layer}, {via_layer}, {bot_layer}')
         for metal_layer in (top_layer, bot_layer):
             if metal_layer in loaded_layers:
                 continue
@@ -142,7 +143,7 @@ def trace_connectivity(
             ))
 
         # Figure out which nets are shorted by vias, then merge them
-        merge_pairs = find_merge_pairs(nets_info.nets, top_layer, bot_layer, via_polys)
+        merge_pairs = find_merge_pairs(nets_info.nets, top_layer, bot_layer, via_polys, clipper_scale_factor)
         for net_a, net_b in merge_pairs:
             nets_info.merge(net_a, net_b)
 
@@ -286,6 +287,7 @@ def find_merge_pairs(
         top_layer: layer_t,
         bot_layer: layer_t,
         via_polys: Optional[Sequence[contour_t]],
+        clipper_scale_factor: int,
         ) -> Set[Tuple[NetName, NetName]]:
     """
     Given a collection of (possibly anonymous) nets, figure out which pairs of
@@ -325,12 +327,23 @@ def find_merge_pairs(
 
             if via_polys is not None:
                 top_bot = intersection_evenodd(top_polys, bot_polys)
-                overlap = intersection_evenodd(top_bot, via_polys)
-                via_polys = difference_evenodd(via_polys, overlap)      # reduce set of via polys for future nets
+                overlap = check_any_intersection(scale_from_clipper(top_bot, clipper_scale_factor),
+                                                 scale_from_clipper(via_polys, clipper_scale_factor))
+#                overlap = intersection_evenodd(top_bot, via_polys)
+#                via_polys = difference_evenodd(via_polys, overlap)      # reduce set of via polys for future nets
             else:
-                overlap = intersection_evenodd(top_polys, bot_polys)  # TODO verify there aren't any suspicious corner cases for this
+#                overlap = intersection_evenodd(top_polys, bot_polys)  # TODO verify there aren't any suspicious corner cases for this
+                overlap = check_any_intersection(scale_from_clipper(top_polys, clipper_scale_factor), scale_from_clipper(bot_polys, clipper_scale_factor))
 
             if overlap:
                 merge_pairs.add(name_pair)
 
     return merge_pairs
+
+
+def check_any_intersection(polys_a, polys_b) -> bool:
+    for poly_a in polys_a:
+        for poly_b in polys_b:
+            if intersects(poly_a, poly_b):
+                return True
+    return False

snarled/poly.py

@@ -65,3 +65,93 @@ def poly_contains_points(
     inside = nontrivial.copy()
     inside[nontrivial] = nontrivial_inside
     return inside
+
+
+def intersects(poly_a: ArrayLike, poly_b: ArrayLike) -> bool:
+    """
+    Check if two polygons overlap and/or touch.
+
+    Args:
+        poly_a: List of vertices, implicitly closed: `[[x0, y0], [x1, y1], ...]`
+        poly_b: List of vertices, implicitly closed: `[[x0, y0], [x1, y1], ...]`
+
+    Returns:
+        `True` if the polygons overlap and/or touch.
+    """
+    poly_a = numpy.array(poly_a, copy=False)
+    poly_b = numpy.array(poly_b, copy=False)
+
+    # Check bounding boxes
+    min_a = poly_a.min(axis=0)
+    min_b = poly_b.min(axis=0)
+    max_a = poly_a.max(axis=0)
+    max_b = poly_b.max(axis=0)
+
+    if ((min_a > max_b) | (min_b > max_a)).all():
+        return False
+
+    #TODO: Check against sorted coords?
+
+    #Check if edges intersect
+    if poly_edges_intersect(poly_a, poly_b):
+        return True
+
+    # Check if either polygon contains the other
+    if poly_contains_points(poly_b, poly_a).any():
+        return True
+
+    if poly_contains_points(poly_a, poly_b).any():
+        return True
+
+    return False
+
+
+def poly_edges_intersect(
+        poly_a: NDArray[numpy.float64],
+        poly_b: NDArray[numpy.float64],
+        ) -> NDArray[numpy.int_]:
+    """
+    Check if the edges of two polygons intersect.
+
+    Args:
+        poly_a: NDArray of vertices, implicitly closed: `[[x0, y0], [x1, y1], ...]`
+        poly_b: NDArray of vertices, implicitly closed: `[[x0, y0], [x1, y1], ...]`
+
+    Returns:
+        `True` if the polygons' edges intersect.
+    """
+    a_next = numpy.roll(poly_a, -1, axis=0)
+    b_next = numpy.roll(poly_b, -1, axis=0)
+
+    # Lists of initial/final coordinates for polygon segments
+    xi1 = poly_a[:, 0, None]
+    yi1 = poly_a[:, 1, None]
+    xf1 = a_next[:, 0, None]
+    yf1 = a_next[:, 1, None]
+
+    xi2 = poly_b[:, 0, None]
+    yi2 = poly_b[:, 1, None]
+    xf2 = b_next[:, 0, None]
+    yf2 = b_next[:, 1, None]
+
+    # Perform calculation
+    dxi = xi1 - xi2
+    dyi = yi1 - yi2
+    dx1 = xf1 - xi1
+    dx2 = xf2 - xi2
+    dy1 = yf1 - yi1
+    dy2 = yf2 - yi2
+
+    numerator_a = dx2 * dyi - dy2 * dxi
+    numerator_b = dx1 * dyi - dy1 * dxi
+    denominator = dy2 * dx1 - dx2 * dy1
+
+    # Avoid warnings since we may multiply eg. NaN*False
+    with numpy.errstate(invalid='ignore', divide='ignore'):
+        u_a = numerator_a / denominator
+        u_b = numerator_b / denominator
+
+        # Find the adjacency matrix
+        adjacency = numpy.logical_and.reduce((u_a >= 0, u_a <= 1, u_b >= 0, u_b <= 1))
+
+    return adjacency.any()