simplifying building rendering and adding distinct rendering of

building=roof and building=greenhouse at z18+

buildings.mss

@@ -2,16 +2,25 @@
 @building-line: darken(@building-fill, 15%);
 @building-low-zoom: darken(@building-fill, 4%);
 
-#buildings,
-#buildings-major {
+#buildings {
   [zoom >= 13] {
     polygon-fill: @building-low-zoom;
     polygon-clip: false;
     [zoom >= 15] {
-      line-color: @building-line;
+      [zoom >= 18] {
+        [building = 'greenhouse'] {
+          a/line-width: 2.5;
+          a/line-offset: -1.25;
+          a/line-color: @land-color;
+        }
+        [building = 'roof'] {
+          b/line-dasharray: 4,1.5;
+        }
+      }
       polygon-fill: @building-fill;
-      line-width: .75;
-      line-clip: false;
+      b/line-color: @building-line;
+      b/line-width: .75;
+      b/line-clip: false;
     }
   }
 }

project.mml

@@ -949,34 +949,11 @@ Layer:
           FROM planet_osm_polygon
           WHERE building IS NOT NULL
             AND building != 'no'
-            AND (aeroway IS NULL OR aeroway != 'terminal')
-            AND (amenity IS NULL OR amenity != 'place_of_worship')
-            AND building != 'train_station'
             AND way_area > 0.01*!pixel_width!::real*!pixel_height!::real
           ORDER BY COALESCE(layer,0), way_area DESC
         ) AS buildings
     properties:
       minzoom: 13
-  - id: buildings-major
-    geometry: polygon
-    <<: *extents
-    Datasource:
-      <<: *osm2pgsql
-      table: |-
-        (SELECT
-            way,
-            building,
-            amenity,
-            aeroway
-          FROM planet_osm_polygon
-          WHERE building IS NOT NULL
-            AND building != 'no'
-            AND (aeroway = 'terminal' OR amenity = 'place_of_worship' OR building = 'train_station')
-            AND way_area > 0.01*!pixel_width!::real*!pixel_height!::real
-          ORDER BY COALESCE(layer,0), way_area DESC)
-        AS buildings_major
-    properties:
-      minzoom: 13
   - id: tunnels
     class: tunnels-fill tunnels-casing access
     geometry: linestring