scripting: create `FN_NAME_INTERNAL_AS_COMPONENT` for implicitly converting some types as components

examples/testbed/scripts/test.lua

@@ -3,9 +3,8 @@ function on_init()
     print("Loaded textured cube")
 
     local pos = Transform.from_translation(Vec3.new(0, 0, -8.0))
-    local cube_comp = ModelComponent.new(cube)
 
-    local e = world:spawn(pos, cube_comp)
+    local e = world:spawn(pos, cube)
     print("spawned entity " .. tostring(e))
 end
 

lyra-scripting/src/lua/mod.rs

@@ -26,13 +26,52 @@ use lyra_ecs::{
     Component, ComponentInfo, World
 };
 use lyra_reflect::{Reflect, TypeRegistry};
+use crate::ScriptBorrow;
 
 pub type LuaContext = Mutex<elua::State>;
 
+/// Name of a Lua function that is used to Reflect the Userdata, but without a value.
+/// 
+/// This is used for reflecting the userdata as an ECS Component or Resource. This **function**
+/// returns a [`ScriptBorrow`] with data as `None`. 
 pub const FN_NAME_INTERNAL_REFLECT_TYPE: &str = "__lyra_internal_reflect_type";
+
+/// Name of a Lua function that is used to Reflect the Userdata.
+/// 
+/// This is used for reflecting the userdata as an ECS Component or Resource. This **method**
+/// returns a [`ScriptBorrow`] with data as `Some`. **Anything that calls this expects the
+/// method to return data**.
 pub const FN_NAME_INTERNAL_REFLECT: &str = "__lyra_internal_reflect";
 
-use crate::ScriptBorrow;
+/// Name of a Lua function implemented for Userdata types that can be made into components.
+/// 
+/// This is used for types that can be converted into components. When implementing this function,
+/// you must return a [`ScriptBorrow`] that contains the component for this userdata.
+/// You can return [`elua::Value::Nil`] if for some reason the type could not be converted
+/// into a component.
+/// 
+/// A good example of this is `LuaResHandle`. The resource handle is requested from the
+/// world, and could be a 3d model. The 3d model could then be manually wrapped as
+/// [`LuaModelComponent`] with its `new` function. But for quality of life, this internal
+/// function was created so that the userdata can be converted into its component
+/// type without having to wrap it.
+/// 
+/// Without implementing this function:
+/// ```lua
+/// local cube = world:request_res("assets/cube-texture-embedded.gltf")
+/// local cube_comp = ModelComponent.new(cube) -- annoying to write
+/// 
+/// local pos = Transform.from_translation(Vec3.new(0, 0, -8.0))
+/// local e = world:spawn(pos, cube_comp)
+/// ```
+/// 
+/// With this function:
+/// /// ```lua
+/// local cube = world:request_res("assets/cube-texture-embedded.gltf")
+/// local pos = Transform.from_translation(Vec3.new(0, 0, -8.0))
+/// local e = world:spawn(pos, cube)
+/// ```
+pub const FN_NAME_INTERNAL_AS_COMPONENT: &str = "__lyra_internal_refl_as_component";
 
 /// A trait used for registering a Lua type with the world.
 pub trait RegisterLuaType {
@@ -140,7 +179,8 @@ impl elua::Userdata for ScriptBorrow {
     }
 }
 
+/// Helper function used for reflecting userdata as a ScriptBorrow
 pub fn reflect_user_data(ud: &elua::AnyUserdata) -> ScriptBorrow {
     ud.execute_method::<_, ScriptBorrow>(FN_NAME_INTERNAL_REFLECT, ())
-        .expect("Type does not implement '__internal_reflect' properly")
+        .expect("Type does not implement internal reflect method properly")
 }

lyra-scripting/src/lua/world.rs

@@ -7,8 +7,7 @@ use lyra_reflect::{ReflectWorldExt, RegisteredType, TypeRegistry};
 use lyra_resource::ResourceManager;
 
 use super::{
-    reflect_user_data, wrappers::LuaResHandle, DynamicViewIter, LuaTableProxyLookup,
-    ReflectLuaProxy, ReflectedIterator, FN_NAME_INTERNAL_REFLECT, FN_NAME_INTERNAL_REFLECT_TYPE,
+    reflect_user_data, wrappers::LuaResHandle, DynamicViewIter, LuaTableProxyLookup, ReflectLuaProxy, ReflectedIterator, FN_NAME_INTERNAL_AS_COMPONENT, FN_NAME_INTERNAL_REFLECT, FN_NAME_INTERNAL_REFLECT_TYPE
 };
 
 impl<'lua> elua::FromLua<'lua> for ScriptEntity {
@@ -79,11 +78,22 @@ impl elua::Userdata for ScriptWorldPtr {
                             Arc::new(elua::Error::runtime("provided component is not userdata")),
                         ))?;
                     
-                    let script_brw = ud.execute_method::<_, ScriptBorrow>(FN_NAME_INTERNAL_REFLECT, ())?;
-                    let reflect = script_brw.reflect_branch.as_component_unchecked();
+                    let comp_borrow = {
+                        if let Ok(as_comp) = ud.get::<_, elua::Function>(FN_NAME_INTERNAL_AS_COMPONENT) {
+                            let ud = match as_comp.exec(ud.clone())? {
+                                elua::Value::Userdata(ud) => ud,
+                                elua::Value::Nil => ud.clone(),
+                                _ => todo!(),
+                            };
 
-                    let refl_data = script_brw.data.unwrap();
-                    //let refl_data = refl_data.as_ref();
+                            ud.execute_method::<_, ScriptBorrow>(FN_NAME_INTERNAL_REFLECT, ())?
+                        } else {
+                            ud.execute_method::<_, ScriptBorrow>(FN_NAME_INTERNAL_REFLECT, ())?
+                        }
+                    };
+
+                    let reflect = comp_borrow.reflect_branch.as_component_unchecked();
+                    let refl_data = comp_borrow.data.unwrap();
                     reflect.bundle_insert(&mut bundle, refl_data);
                 }
 

lyra-scripting/src/lua/wrappers/delta_time.rs

@@ -22,13 +22,13 @@ impl std::ops::DerefMut for LuaDeltaTime {
 }
 
 impl<'lua> elua::FromLua<'lua> for LuaDeltaTime {
-    fn from_lua(lua: &'lua elua::State, value: elua::Value<'lua>) -> elua::Result<Self> {
+    fn from_lua(_: &'lua elua::State, _: elua::Value<'lua>) -> elua::Result<Self> {
         todo!()
     }
 }
 
 impl<'lua> elua::AsLua<'lua> for LuaDeltaTime {
-    fn as_lua(self, lua: &'lua elua::State) -> elua::Result<elua::Value<'lua>> {
+    fn as_lua(self, _: &'lua elua::State) -> elua::Result<elua::Value<'lua>> {
         Ok(elua::Value::Number(*self.0 as f64))
     }
 }

lyra-scripting/src/lua/wrappers/model_comp.rs

@@ -1,7 +1,7 @@
 use std::any::TypeId;
 use std::{cell::Ref, sync::Arc};
 
-use elua::{AsLua, FromLua};
+use elua::FromLua;
 use lyra_game::scene::ModelComponent;
 use lyra_reflect::Reflect;
 use lyra_resource::{Model, ResHandle};
@@ -13,7 +13,7 @@ use crate::{lua::{FN_NAME_INTERNAL_REFLECT, FN_NAME_INTERNAL_REFLECT_TYPE}, Scri
 use super::LuaResHandle;
 
 #[derive(Clone, Reflect)]
-pub struct LuaModelComponent(ModelComponent);
+pub struct LuaModelComponent(pub ModelComponent);
 
 impl elua::Userdata for LuaModelComponent {
     fn name() -> String {
@@ -44,7 +44,8 @@ impl elua::Userdata for LuaModelComponent {
         })
         .function(FN_NAME_INTERNAL_REFLECT_TYPE, |_, ()| {
             Ok(ScriptBorrow::from_component::<ModelComponent>(None))
-        }).method(FN_NAME_INTERNAL_REFLECT, |_, this, ()| {
+        })
+        .method(FN_NAME_INTERNAL_REFLECT, |_, this, ()| {
             Ok(ScriptBorrow::from_component(Some(this.0.clone())))
         });
 

lyra-scripting/src/lua/wrappers/res_handle.rs

@@ -1,7 +1,12 @@
 use std::{ops::Deref, sync::Arc};
 
-use elua::FromLua;
-use lyra_resource::ResourceStorage;
+use elua::{AsLua, FromLua};
+use lyra_game::scene::ModelComponent;
+use lyra_resource::{Model, ResHandle, ResourceStorage};
+
+use crate::lua::FN_NAME_INTERNAL_AS_COMPONENT;
+
+use super::LuaModelComponent;
 
 #[derive(Clone)]
 pub struct LuaResHandle(pub Arc<dyn ResourceStorage>);
@@ -46,6 +51,18 @@ impl elua::Userdata for LuaResHandle {
             Ok(this.is_loaded())
         });
 
+        builder.method(FN_NAME_INTERNAL_AS_COMPONENT, |lua, this, ()| {
+            let any = this.0.as_any();
+            match any.downcast_ref::<ResHandle<Model>>() {
+                Some(model) => {
+                    LuaModelComponent(ModelComponent(model.clone())).as_lua(lua)
+                },
+                None => {
+                    Ok(elua::Value::Nil)
+                }
+            }
+        });
+
         Ok(())
     }
 }