remove duplicated legacy code, add a get_cavern_value method, and store registered layers by name

init.lua

@@ -276,8 +276,6 @@ subterrane.register_layer = function(cave_layer_def)
 		error_out = true
 	end
 	if error_out then return end
-	
-	local cave_name = cave_layer_def.name
 
 	subterrane.set_defaults(cave_layer_def)
 	
@@ -287,21 +285,26 @@ subterrane.register_layer = function(cave_layer_def)
 	if cave_layer_def.name == nil then
 		cave_layer_def.name = tostring(YMIN) .. " to " .. tostring(YMAX)
 	end
-	
-	table.insert(subterrane.registered_layers, cave_layer_def)
+
+	local cave_name = cave_layer_def.name
+
+	if subterrane.registered_layers[cave_name] ~= nil then
+		minetest.log("warning", "[subterrane] cave layer def " .. tostring(cave_name) .. " has already been registered. Overriding with new definition.")
+	end
+	subterrane.registered_layers[cave_name] = cave_layer_def
 
 	local block_size = mapgen_helper.block_size
 	
 	if (YMAX+32+1)%block_size ~= 0 then
 		local boundary = YMAX -(YMAX+32+1)%block_size
 		minetest.log("warning", "[subterrane] The y_max setting "..tostring(YMAX)..
-			" for cavern layer " .. cave_layer_def.name .. " is not aligned with map chunk boundaries. Consider "..
+			" for cavern layer " .. cave_name .. " is not aligned with map chunk boundaries. Consider "..
 			tostring(boundary) .. " or " .. tostring(boundary+block_size) .. " for maximum mapgen efficiency.")
 	end
 	if (YMIN+32)%block_size ~= 0 then
 		local boundary = YMIN - (YMIN+32)%block_size
 		minetest.log("warning", "[subterrane] The y_min setting "..tostring(YMIN)..
-			" for cavern layer " .. cave_layer_def.name .. " is not aligned with map chunk boundaries. Consider "..
+			" for cavern layer " .. cave_name .. " is not aligned with map chunk boundaries. Consider "..
 			tostring(boundary) .. " or " .. tostring(boundary+block_size) .. " for maximum mapgen efficiency.")
 	end
 

legacy.lua

@@ -448,26 +448,6 @@ function subterrane:vertically_consistent_random(vi, area)
 	return subterrane:vertically_consistent_randomp(pos)
 end
 
-subterrane.get_column_points = function(minp, maxp, column_def)
-	local grids = mapgen_helper.get_nearest_regions(minp, grid_size)
-	local points = {}
-	for _, grid in ipairs(grids) do
-		--The y value of the returned point will be the radius of the column
-		local minp = {x=grid.x, y = column_def.min_column_radius*100, z=grid.z}
-		local maxp = {x=grid.x+grid_size-1, y=column_def.max_column_radius*100, z=grid.z+grid_size-1}
-		for _, point in ipairs(mapgen_helper.get_random_points(minp, maxp, column_def.minimum_count, column_def.maximum_count)) do
-			point.y = point.y / 100
-			if point.x > minp.x - point.y
-				and point.x < maxp.x + point.y
-				and point.z > minp.z - point.y
-				and point.z < maxp.z + point.y then
-				table.insert(points, point)
-			end			
-		end
-	end
-	return points
-end
-
 subterrane.get_point_heat = function(pos, points)
 	local heat = 0
 	for _, point in ipairs(points) do

test_pos.lua

@@ -38,4 +38,28 @@ subterrane.is_in_cavern = function(pos)
 	end
 	
 	return results
+end
+
+-- returns the value of the cavern field at a particular location for a particular cavern definition.
+subterrane.get_cavern_value = function(name, pos)
+	local cave_layer_def = subterrane.registered_layers[name]
+	
+	local YMIN = cave_layer_def.y_min
+	local YMAX = cave_layer_def.y_max
+	local y = pos.y
+	if y > YMAX or y < YMIN then
+		return nil
+	end
+
+	local block_size = mapgen_helper.block_size
+	local BLEND = math.min(cave_layer_def.boundary_blend_range, (YMAX-YMIN)/2)
+	local TCAVE = cave_layer_def.cave_threshold
+	local np_cave = cave_layer_def.perlin_cave
+	local np_wave = cave_layer_def.perlin_wave
+	local y_blend_min = YMIN + BLEND * 1.5
+	local y_blend_max = YMAX - BLEND * 1.5	
+	local nval_cave = minetest.get_perlin(np_cave):get_3d(pos) --cave noise for structure
+	local nval_wave = minetest.get_perlin(np_wave):get_3d(pos) --wavy structure of cavern ceilings and floors
+	nval_cave = (nval_cave + nval_wave)/2
+	return nval_cave
 end