improve scad rendering

src/c3nav/mapdata/models/level.py

@@ -13,7 +13,7 @@ from shapely.ops import cascaded_union
 
 from c3nav.mapdata.models.locations import SpecificLocation
 from c3nav.mapdata.utils.geometry import assert_multipolygon
-from c3nav.mapdata.utils.scad import polygon_scad
+from c3nav.mapdata.utils.scad import add_indent, polygon_scad
 from c3nav.mapdata.utils.svg import SVGImage
 
 
@@ -203,19 +203,19 @@ class Level(SpecificLocation, models.Model):
                 geometry = geometry.difference(intersection)
 
                 low_height = max(altitude - low_altitude, 0)
-                total_heght = low_height+height
-                if total_heght:
+                total_height = low_height+height
+                if total_height:
                     f.write('    ')
                     f.write('translate([0, 0, %.2f]) ' % (altitude - low_height))
-                    f.write('linear_extrude(height=%.2f, center=false, convexity=20) ' % total_heght)
-                    f.write(polygon_scad(intersection) + ';\n')
+                    f.write(add_indent(polygon_scad(intersection, total_height))[4:])
         if not geometry.is_empty:
             f.write('    ')
             f.write('translate([0, 0, %.2f]) ' % (altitude - Decimal('0.5')))
-            f.write('linear_extrude(height=%.2f, center=false, convexity=20) ' % (height+Decimal('0.5')))
-            f.write(polygon_scad(geometry) + ';\n')
+            f.write(add_indent(polygon_scad(geometry, height+Decimal('0.5')))[4:])
 
     def _render_scad(self, f, low_clip=(), spaces=None, request=None):
+        f.write('    // '+self.title+'\n')
+
         if spaces is None:
             from c3nav.mapdata.models import Area, Space
             spaces = self.spaces.filter(Space.q_for_request(request, allow_none=True)).prefetch_related(
@@ -224,6 +224,8 @@ class Level(SpecificLocation, models.Model):
                 'stairs', 'obstacles', 'lineobstacles'
             )
 
+        f.write('')
+
         for area in self.altitudeareas.all():
             area.geometry = area.geometry.buffer(0)
             self._render_scad_polygon(f, area.geometry, area.altitude, low_clip=low_clip)

src/c3nav/mapdata/utils/scad.py

@@ -1,29 +1,41 @@
 import json
-from itertools import chain
+from decimal import Decimal
 
 from shapely.geometry import mapping
 
 from c3nav.mapdata.utils.geometry import assert_multipolygon
 
 
-def polygon_scad(polygon):
-    results = [_polygon_scad(polygon) for polygon in assert_multipolygon(polygon)]
+def polygon_scad(polygon, height):
+    results = [_polygon_scad(polygon, height=height) for polygon in assert_multipolygon(polygon)]
     if not results:
         raise ValueError
     if len(results) == 1:
         return results[0]
-    return '{ '+'; '.join(results)+'; }'
+    return 'union() {\n'+add_indent(''.join(results))+'}\n'
 
 
-def _polygon_scad(polygon):
-    coords = mapping(polygon)['coordinates']
-    result = 'polygon(points='+json.dumps(tuple(chain(*coords)), separators=(',', ':'))
-    if len(coords) > 1:
-        paths = []
-        start = 0
-        for subcoords in coords:
-            paths.append(tuple(range(start, len(subcoords))))
-            start += len(subcoords)
-        result += ', paths='+json.dumps(paths, separators=(',', ':'))
-    result += ', convexity=20)'
+def _polygon_scad(polygon, height):
+    coords = mapping(polygon.simplify(0.001))['coordinates']
+
+    interior = coords[0]
+    exteriors = coords[1:]
+    result = 'linear_extrude(height=%.2f, center=false, convexity=20) ' % height
+    result += _ring_scad(interior)
+    if exteriors:
+        result = 'difference() {\n'+add_indent(result)
+        result += '    translate([0, 0, -0.01]) {\n'
+        for ring in exteriors:
+            result += '        linear_extrude(height=%.2f, center=false, convexity=20) ' % (height+Decimal('0.02'))
+            result += _ring_scad(ring)
+        result += '    }\n'
+        result += '}\n'
     return result
+
+
+def _ring_scad(coords):
+    return 'polygon(points='+json.dumps(coords[:-1], separators=(',', ':'))+', convexity=20);\n'
+
+
+def add_indent(text):
+    return '    '+text.replace('\n', '\n    ')[:(-4 if text.endswith('\n') else None)]