Fix bad noise analysis if persistence < 0

init.lua

@@ -346,9 +346,24 @@ local analyze_noiseparams = function(noiseparams)
 	local o_min, o_max = 0, 0
 	for o=1, np.octaves do
 		local exp = o-1
-		o_max = o_max + (1 * np.persistence ^ exp)
+		-- Calculate the two possible extreme values
+		-- with the octave value being either at 1 or -1.
+		local limit1 = (1 * np.persistence ^ exp)
+		local limit2 = (-1 * np.persistence ^ exp)
+
+		-- To add to the maximum, pick the higher value
+		if limit1 > limit2 then
+			o_max = o_max + limit1
+		else
+			o_max = o_max + limit2
+		end
 		if not is_absolute then
-			o_min = o_min + (- 1 * np.persistence ^ exp)
+			-- To add to the minimum, pick the LOWER value
+			if limit1 > limit2 then
+				o_min = o_min + limit2
+			else
+				o_min = o_min + limit1
+			end
 			-- Note: If absvalue flag is set, the sum of the octaves
 			-- is always 0, so we don't need to calculate it
 		end