avoid merging intersecting polygons too early

src/c3nav/mapdata/render/engines/base.py

@@ -69,7 +69,7 @@ class RenderEngine(ABC):
         pass
 
     def add_geometry(self, geometry, fill: Optional[FillAttribs] = None, stroke: Optional[StrokeAttribs] = None,
-                     altitude=None, height=None, shape_cache_key=None, category=None):
+                     altitude=None, height=None, shape_cache_key=None, category=None, item=None):
         # draw a shapely geometry with a given style
         # altitude is the absolute altitude of the upper bound of the element
         # height is the height of the element
@@ -79,12 +79,12 @@ class RenderEngine(ABC):
         if geometry.is_empty:
             return
 
-        self._add_geometry(geometry=geometry, fill=fill, stroke=stroke,
+        self._add_geometry(geometry=geometry, fill=fill, stroke=stroke, altitude=altitude, height=height,
-                           altitude=altitude, height=height, shape_cache_key=shape_cache_key, category=category)
+                           shape_cache_key=shape_cache_key, category=category, item=item)
 
     @abstractmethod
     def _add_geometry(self, geometry, fill: Optional[FillAttribs], stroke: Optional[StrokeAttribs],
-                      altitude=None, height=None, shape_cache_key=None):
+                      altitude=None, height=None, shape_cache_key=None, item=None):
         pass
 
     def set_mesh_lookup_data(self, data):

src/c3nav/mapdata/render/engines/base3d.py

@@ -32,13 +32,13 @@ class Base3DEngine(RenderEngine):
         self._current_group = group
         self.groups.setdefault(group, [])
 
-    def _add_geometry(self, geometry, fill: Optional[FillAttribs], stroke: Optional[StrokeAttribs], category=None,
+    def _add_geometry(self, geometry, fill: Optional[FillAttribs], stroke: Optional[StrokeAttribs],
-                      **kwargs):
+                      category=None, item=None, **kwargs):
         if fill is not None:
             key = '%s_%s' % (self._current_group, category)
             if key not in self.vertices:
                 self.groups[self._current_group].append(key)
-            self.vertices.setdefault(key, []).append(self._place_geometry(geometry))
+            self.vertices.setdefault(key, OrderedDict()).setdefault(item, []).append(self._place_geometry(geometry))
             self.colors.setdefault(key, self.color_to_rgb(fill.color))
 
     @staticmethod

src/c3nav/mapdata/render/engines/openscad.py

@@ -8,13 +8,12 @@ from c3nav.mapdata.render.engines.base3d import Base3DEngine
 class OpenSCADEngine(Base3DEngine):
     filetype = 'scad'
 
-    def _create_polyhedron(self, name, vertices):
+    def _create_polyhedron(self, vertices):
         facets = np.vstack(vertices)
         vertices = tuple(set(tuple(vertex) for vertex in facets.reshape((-1, 3))))
         lookup = {vertex: i for i, vertex in enumerate(vertices)}
 
-        return (b'module ' + name.replace('-', 'minus').encode() + b'() {\n' +
+        return (b'  polyhedron(\n' +
-                b'  polyhedron(\n' +
                 b'    points = [\n' +
                 b'\n'.join((b'      [%.3f, %.3f, %.3f],' % tuple(vertex)) for vertex in vertices) + b'\n' +
                 b'    ],\n' +
@@ -23,8 +22,7 @@ class OpenSCADEngine(Base3DEngine):
                            for a, b, c in facets) + b'\n' +
                 b'    ],\n' +
                 b'    convexity = 10\n' +
-                b'  );\n'
+                b'  );')
-                b'}\n')
 
     def render(self) -> bytes:
         result = (b'c3nav_export();\n\n' +
@@ -41,5 +39,7 @@ class OpenSCADEngine(Base3DEngine):
                        b'}\n')
         result += b'\n'
         for group, vertices in self.vertices.items():
-            result += self._create_polyhedron(group, vertices)
+            result += (b'module ' + group.replace('-', 'minus').encode() + b'() {\n' +
+                       b'\n'.join(self._create_polyhedron(v) for v in vertices.values()) +
+                       b'}\n')
         return result

src/c3nav/mapdata/render/engines/svg.py

@@ -215,7 +215,7 @@ class SVGEngine(RenderEngine):
             self.altitudes[new_altitude] = new_geometry
 
     def _add_geometry(self, geometry, fill: Optional[FillAttribs], stroke: Optional[StrokeAttribs],
-                      altitude=None, height=None, shape_cache_key=None, category=None):
+                      altitude=None, height=None, shape_cache_key=None, **kwargs):
         geometry = self.buffered_bbox.intersection(geometry.geom)
 
         if geometry.is_empty:

src/c3nav/mapdata/render/renderer.py

@@ -107,21 +107,21 @@ class MapRenderer:
                 engine.add_geometry(geoms.walls_bottom.fit(scale=geoms.min_altitude-min_altitude,
                                                            offset=min_altitude-int(0.7*1000)),
                                     fill=FillAttribs('#aaaaaa'), category='walls')
-                for altitudearea in geoms.altitudeareas:
+                for i, altitudearea in enumerate(geoms.altitudeareas):
                     scale = (altitudearea.altitude - min_altitude) / int(0.7 * 1000)
                     offset = (min_altitude - int(0.7*1000)) - (altitudearea.altitude - int(0.7*1000)) * scale
                     geometry = altitudearea.geometry.difference(crop_areas)
                     engine.add_geometry(geometry.fit(scale=scale, offset=offset).filter(top=False),
-                                        fill=FillAttribs('#eeeeee'), category='ground')
+                                        fill=FillAttribs('#eeeeee'), category='ground', item=i)
 
             # render altitude areas in default ground color and add ground colors to each one afterwards
             # shadows are directly calculated and added by the engine
-            for altitudearea in geoms.altitudeareas:
+            for i, altitudearea in enumerate(geoms.altitudeareas):
                 geometry = altitudearea.geometry.difference(crop_areas)
                 if not_full_levels:
                     geometry = geometry.filter(bottom=False)
                 engine.add_geometry(geometry, altitude=altitudearea.altitude, fill=FillAttribs('#eeeeee'),
-                                    category='ground')
+                                    category='ground', item=i)
 
                 i = 0
                 for color, areas in altitudearea.colors.items():
@@ -130,7 +130,8 @@ class MapRenderer:
                                   if access_restriction in unlocked_access_restrictions)
                     if areas:
                         i += 1
-                        engine.add_geometry(hybrid_union(areas), fill=FillAttribs(color), category='groundcolor%s' % i)
+                        engine.add_geometry(hybrid_union(areas), fill=FillAttribs(color),
+                                            category='groundcolor%s' % i, item=i)
 
             # add walls, stroke_px makes sure that all walls are at least 1px thick on all zoom levels,
             walls = None