Generate grid directly in pregenerate.lua, not in a function

gridmanager.lua

@@ -69,25 +69,6 @@ function mapgen_rivers.try_load_grid(grid)
 	return true
 end
 
-function mapgen_rivers.generate_grid()
-	minetest.log("action", '[mapgen_rivers] Generating grid, this may take a while...')
-	local grid = {}
-
-	local blocksize = mapgen_rivers.settings.blocksize
-	local xsize = math.floor(mapgen_rivers.settings.map_x_size / blocksize)
-	local zsize = math.floor(mapgen_rivers.settings.map_z_size / blocksize)
-	grid.size = {x=xsize, y=zsize}
-
-	if not mapgen_rivers.pregenerate then
-		minetest.log("error", "[mapgen_rivers] Pre-generation function is not available.")
-		return false
-	end
-
-	mapgen_rivers.pregenerate(grid)
-
-	return grid
-end
-
 function mapgen_rivers.write_grid(grid)
 	minetest.mkdir(world_data)
 

init.lua

@@ -17,9 +17,7 @@ minetest.register_on_mods_loaded(function()
 	local exist = mapgen_rivers.try_load_grid()
 
 	if not exist then -- If grid does not exist yet, generate it
-		dofile(modpath .. 'pregenerate.lua')
+		local grid = dofile(modpath .. 'pregenerate.lua')
-
-		local grid = mapgen_rivers.generate_grid()
 		mapgen_rivers.write_grid(grid)
 		mapgen_rivers.try_load_grid() -- Reload if needed
 	end

pregenerate.lua

@@ -21,6 +21,9 @@ local use_margin = mapgen_rivers.settings.margin
 local margin_width = mapgen_rivers.settings.margin_width / blocksize
 local margin_elev = mapgen_rivers.settings.margin_elev
 
+local X = math.floor(mapgen_rivers.settings.map_x_size / blocksize)
+local Y = math.floor(mapgen_rivers.settings.map_z_size / blocksize)
+
 local function margin(dem, width, elev)
 	local X, Y = dem.X, dem.Y
 	for i=1, width do
@@ -49,33 +52,36 @@ local function margin(dem, width, elev)
 	end
 end
 
-function mapgen_rivers.pregenerate(grid)
+-- Generate the grid
-	local size = grid.size
 
-	if size.x * size.y > 4e6 then
+minetest.log("action", '[mapgen_rivers] Generating grid, this may take a while...')
+
+local grid = {size={x=X, y=Y}}
+
+if X*Y > 4e6 then
 	minetest.log("warning", "[mapgen_rivers] You are going to generate a very large grid (>4M nodes). If you experience problems, you should increase blocksize or reduce map size.")
-	end
+end
 
-	local seed = tonumber(minetest.get_mapgen_setting("seed"):sub(-10))
+local seed = tonumber(minetest.get_mapgen_setting("seed"):sub(-10))
-	np_base.seed = (np_base.seed or 0) + seed
+np_base.seed = (np_base.seed or 0) + seed
 
-	local nobj_base = PerlinNoiseMap(np_base, {x=size.x, y=1, z=size.y})
+local nobj_base = PerlinNoiseMap(np_base, {x=X, y=1, z=Y})
 
-	local dem = nobj_base:get_3d_map_flat({x=0, y=0, z=0})
+local dem = nobj_base:get_3d_map_flat({x=0, y=0, z=0})
-	dem.X = size.x
+dem.X = X
-	dem.Y = size.y
+dem.Y = Y
 
-	if use_margin then
+if use_margin then
 	margin(dem, margin_width, margin_elev)
-	end
+end
 
-	local model = EvolutionModel(evol_params)
+local model = EvolutionModel(evol_params)
-	model.dem = dem
+model.dem = dem
-	local ref_dem = model:define_isostasy(dem)
+local ref_dem = model:define_isostasy(dem)
 
-	local tectonic_step = tectonic_speed * time_step
+local tectonic_step = tectonic_speed * time_step
-	collectgarbage()
+collectgarbage()
-	for i=1, niter do
+for i=1, niter do
 	minetest.log("info", "[mapgen_rivers] Iteration " .. i .. " of " .. niter)
 
 	model:diffuse(time_step)
@@ -92,23 +98,24 @@ function mapgen_rivers.pregenerate(grid)
 	end
 
 	collectgarbage()
-	end
+end
-	model:flow()
+model:flow()
 
-	local mfloor = math.floor
+local mfloor = math.floor
-	local mmin, mmax = math.min, math.max
+local mmin, mmax = math.min, math.max
-	local offset_x, offset_y = twist(model.dirs, model.rivers, 5)
+local offset_x, offset_y = twist(model.dirs, model.rivers, 5)
-	for i=1, size.x*size.y do
+for i=1, X*Y do
 	offset_x[i] = mmin(mmax(offset_x[i]*256, -128), 127)
 	offset_y[i] = mmin(mmax(offset_y[i]*256, -128), 127)
-	end
-
-	grid.dem = model.dem
-	grid.lakes = model.lakes
-	grid.dirs = model.dirs
-	grid.rivers = model.rivers
-	grid.offset_x = offset_x
-	grid.offset_y = offset_y
-
-	collectgarbage()
 end
+
+grid.dem = model.dem
+grid.lakes = model.lakes
+grid.dirs = model.dirs
+grid.rivers = model.rivers
+grid.offset_x = offset_x
+grid.offset_y = offset_y
+
+collectgarbage()
+
+return grid