added segment_weighted_pattern builder

map_gen/shared/builders.lua

@@ -22,6 +22,8 @@ local tau = math.tau
 local loga = math.log
 local shallow_copy = table.shallow_copy
 local remove = table.remove
+local binary_search = table.binary_search
+local bnot = bit32.bnot
 
 -- helpers
 
@@ -1454,15 +1456,34 @@ end
 --- Docs: https://github.com/Refactorio/RedMew/wiki/Using-the-Builders#builderssegment_pattern
 function Builders.segment_pattern(pattern)
     local count = #pattern
+    local count_by_tau = count / tau
 
     return function(x, y, world)
         local angle = atan2(-y, x)
-        local index = floor(angle / tau * count) % count + 1
+        local index = floor(angle * count_by_tau) % count + 1
         local shape = pattern[index] or Builders.empty_shape
         return shape(x, y, world)
     end
 end
 
+function Builders.segment_weighted_pattern(pattern)
+    local weights = Builders.prepare_weighted_array(pattern)
+    local total = weights.total * 0.5
+
+    return function(x, y, world)
+        local angle = atan2(-y, x)
+        local i = (angle * inv_pi + 1) * total
+
+        local index = binary_search(weights, i)
+        if index < 0 then
+            index = bnot(index)
+        end
+
+        local shape = pattern[index].shape or Builders.empty_shape
+        return shape(x, y, world)
+    end
+end
+
 --- Docs: https://github.com/Refactorio/RedMew/wiki/Using-the-Builders#builderspyramid_pattern
 function Builders.pyramid_pattern(pattern, columns, rows, width, height)
     local half_width = width / 2