Add the intro cutscene, a start to the map, and various other things.

mods/artifact_characters/init.lua

@@ -1,6 +1,8 @@
 
 local ns = artifact
 
+local db = minetest.get_mod_storage()
+
 function ns.apply_key(m)
     m.object:set_properties {
         textures = {"artifact_key.png"},
@@ -10,6 +12,17 @@ function ns.apply_key(m)
     m.eye_height = 1.6
     -- Switch hand appearance.
     m.inv:set_stack("main", 1, ItemStack("input_"..m.character))
+    if m.healthbar then
+        m.object:hud_change(m.healthbar, "text", "artifact_heart.png")
+    end
+    m.blackrod = minetest.add_entity(m.object:get_pos(), "display")
+    m.blackrod:set_properties {
+        visual = "mesh",
+        mesh = "artifact_blackrod.obj",
+        textures = {"artifact_blackrod.png"},
+        visual_size = vector.new(1,1,1) *10
+    }
+    m.blackrod:set_attach(m.object, "RightArm", vector.new(0.25, -5.5, 0), vector.new(90,0,0))
 end
 
 function ns.apply_vix(m)
@@ -21,19 +34,135 @@ function ns.apply_vix(m)
     m.eye_height = 1.5
     -- Switch hand appearance.
     m.inv:set_stack("main", 1, ItemStack("input_"..m.character))
+    m.object:hud_change(m.healthbar, "text", "artifact_heart_vix.png")
+    if m.blackrod then
+        m.blackrod:remove()
+        m.blackrod = nil
+    end
 end
 
 function ns.swap_character(m)
     if m.character == "vix" then
+        artifact.sidekick.character = "vix"
         m:set_character("key")
         ns.apply_key(m)
     else
+        artifact.sidekick.character = "key"
         m:set_character("vix")
         ns.apply_vix(m)
     end
+    
+    if artifact.sidekick.ref then
+        -- `m.pos` includes eye_height, and we don't want that here.
+        local pos = m.object:get_pos()
+        local yaw = m.yaw
+        local pitch = m.pitch
+        m.object:set_pos(artifact.sidekick.ref.object:get_pos())
+        m.object:set_look_horizontal(artifact.sidekick.yaw)
+        m.object:set_look_vertical(artifact.sidekick.pitch)
+        artifact.sidekick.ref.object:set_pos(pos)
+        artifact.sidekick.ref.object:set_yaw(yaw)
+        artifact.sidekick.ref.object:set_bone_override("Head", m.object:get_bone_override("Head"))
+        artifact.sidekick.ref.object:set_bone_override("root", m.object:get_bone_override("root"))
+        artifact.sidekick.pos = pos
+        artifact.sidekick.yaw = yaw
+        artifact.sidekick.pitch = pitch
+
+        local e = artifact.sidekick.ref
+        if artifact.sidekick.character == "vix" then
+            artifact.sidekick.ref.object:set_properties {
+                textures = {"artifact_vix.png"},
+                visual_size = vector.new(1,1,1) *0.8
+            }
+            if e.blackrod then
+                e.blackrod:remove()
+            end
+        else
+            e.object:set_properties {
+                textures = {"artifact_key.png"},
+                visual_size = vector.new(1,1,1) *0.88
+            }
+            e.blackrod = minetest.add_entity(e.object:get_pos(), "display")
+            e.blackrod:set_properties {
+                visual = "mesh",
+                mesh = "artifact_blackrod.obj",
+                textures = {"artifact_blackrod.png"},
+                visual_size = vector.new(1,1,1) *10
+            }
+            e.blackrod:set_attach(e.object, "RightArm", vector.new(0.25, -5.5, 0), vector.new(90,0,0))
+        end
+    end
+    artifact.sidekick.save()
 end
 
 
 
 include "key.lua"
 include "vix.lua"
+
+artifact.sidekick = setmetatable(minetest.deserialize(db:get("sidekick") or "return nil") or {
+    pos = vector.zero(),
+    pitch = 0,
+    yaw = 0,
+    character = "vix",
+}, {
+    __index = {
+        save = function()
+            local ref = artifact.sidekick.ref
+            -- Temporarily erase the entity so we can serialize properly.
+            artifact.sidekick.ref = nil
+            db:set_string("sidekick", minetest.serialize(artifact.sidekick))
+            artifact.sidekick.ref = ref
+        end
+    }
+})
+
+minetest.register_entity(":artifact:sidekick", {
+    initial_properties = {
+        visual = "mesh",
+        mesh = "artifact_character.gltf",
+        textures = {"artifact_key.png"},
+        physical = true,
+        collisionbox = {
+            -0.3, 0,-0.3,
+            0.3, 1.77, 0.3
+        }
+    },
+    _interact_marker_offset = function() return vector.new(0, 1.1,0) end,
+    _interact_time = 0.4,
+    on_activate = function(e, data)
+        if data then
+            extend(e, minetest.deserialize(data) or {})
+        end
+        if artifact.sidekick.character == "vix" then
+            e.object:set_properties {
+                textures = {"artifact_key.png"},
+                visual_size = vector.new(1,1,1) *0.88
+            }
+        end
+        -- Gravity.
+        e.object:set_acceleration(vector.new(0,-9.81,0))
+        -- Make quite sure that we only ever have one of these.
+        -- Remove this one because the first one we spawned is _probably_ the
+        -- right one (e.g. if someone got unloaded, then loaded again after
+        -- a replacement was spawned).
+        if artifact.sidekick.ref then
+            e.object:remove()
+            return
+        else
+            artifact.sidekick.ref = e
+        end
+    end,
+    on_deactivate = function(e)
+        artifact.sidekick.ref = nil
+    end,
+    get_staticdata = function(e)
+        return minetest.serialize{
+            cahracter = e.character
+        }
+    end,
+    on_interact = function(e, m)
+        ns.swap_character(m)
+    end
+})
+