use gravity_manager

.luacheckrc

@@ -18,5 +18,5 @@ read_globals = {
 	"dump", "VoxelArea",
 
 	-- Deps
-	"default"
+	"default", "gravity_manager"
 }

depends.txt

@@ -2,3 +2,4 @@ default
 vacuum?
 bedrock?
 skybox?
+gravity_manager?

skybox.lua

@@ -1,16 +1,24 @@
 local has_skybox_mod = minetest.get_modpath("skybox")
+local has_gravity_manager_mod = minetest.get_modpath("gravity_manager")
 
 local min_y = planet_mars.y_start
 local cave_end_y = planet_mars.y_start + (planet_mars.y_height * 0.97)
 local max_y = planet_mars.y_start + planet_mars.y_skybox_height
 
+if has_gravity_manager_mod then
+	gravity_manager.register({
+		miny = min_y,
+		maxy = max_y,
+		gravity = 0.37
+	})
+end
+
 if has_skybox_mod then
 	skybox.register({
 		-- http://www.custommapmakers.org/skyboxes.php
 		name = "mars",
 		miny = cave_end_y,
 		maxy = max_y,
-		gravity = 0.37,
 		always_day = true,
 		clouds = {
 			thickness=64,
@@ -34,7 +42,6 @@ if has_skybox_mod then
 		name = "mars_cave",
 		miny = min_y,
 		maxy = cave_end_y,
-		gravity = 0.37,
 		always_day = true,
 		sky_type = "plain",
 		sky_color = {r=244, g=189, b=114}