Hi everyone,
I've been attempting to start my game with the Appkit as the basis for all my Lua. However, I've found that trying to work out anything to do with the Appkit is extremely tedious. I'll use what I'm currently trying to do as an example, which is set up my own Camera system as it needs a lot more functionality than what you recieve from the Appkit out of the box. I've been looking at how to create a new camera with Lua, and then set it as the active camera. Tracing the path in which the free_cam_player is created in the Appkit has left me quite confused.
I think I've narrowed down the main functions to do with creating the free_cam_player. The first is the PlayerUtil.spawn_free_cam_player() function in player_util:
function PlayerUtil.spawn_free_cam_player(level, camera_unit, camera_index, position, rotation, input_mapper)
-- A container for the freecam objects
local free_cam_player = {}
free_cam_player.unit = camera_unit
-- Camera
local camera = CameraWrapper(free_cam_player, camera_unit, camera_index)
camera:set_local_position(position)
camera:set_local_rotation(rotation)
camera:enable()
-- Add camera input movement. Starts enabled.
local controller = UnitController(free_cam_player, camera_unit, input_mapper)
controller:set_move_speed(free_cam_move_speed:unbox())
controller:set_yaw_speed(free_cam_yaw_speed)
controller:set_pitch_speed(free_cam_pitch_speed)
return free_cam_player
endObviously the next important function being the CameraWrapper() function it calls when it creates the local variable 'camera' above.. this one is from the camera_wrapper.lua:
function CameraWrapper:init(entity, unit, camera_index)
self.entity = entity -- object this component is associated with, can be used to access other components
self.unit = unit
self.camera = Unit.camera(unit, camera_index)
self.world = Unit.world(unit)
self.is_enabled = false
CameraWrapper.manager:add_component(entity, self, Unit.level(unit))
end
(took out a few irrelevant lines from the function above)
1) Why is the first parameter that the init function takes named 'entity'? This confuses me as I believe they're using the term to just describe a table that they've stored information in, however that's in conflict with an actual namespace 'stingray.Entity' which can just make it confusing to read.
2) When passing the 'entity' into this function, it's also passing the camera_unit as it was added to the table being passed in in the previous function here:
-- A container for the freecam objects
local free_cam_player = {}
free_cam_player.unit = camera_unitso wouldn't you then just retrieve the camera_unit information from the 'entity'?
3) What IS the camera_unit? I can see it references an actual .unit file in the Appkit.. is this camera_unit used for all cameras you create? They all reference the same unit? How do you create/can you create a camera without using this?
4) The line:
self.camera = Unit.camera(unit, camera_index)
Does this just retrieve the actual Camera? i.e. the stingray.Camera object?
5) I can't see anywhere in here that the camera is actually created, only that you've made a table, storing the location of a .unit file which you then use to somehow get a camera.. but where does that camera come from? This reverts to questions 3.. what is the camera_unit?
6) How do you set the active camera? I understand the camera_wrapper.lua has this function:
function CameraWrapper:enable()
if self.enabled == true then return end
local world_wrapper = Appkit.managed_world
if world_wrapper and world_wrapper.world == self.world then
world_wrapper:set_camera_enabled(self.camera, self.unit, true)
self.is_enabled = true
end
end
which calls this function from the world_wrapper.lua script:
function WorldWrapper:set_camera_enabled(camera, unit, enabled)
if not camera then return end
if enabled == true then
self.enabled_cameras[camera] = unit
else
self.enabled_cameras[camera] = nil
end
end
which sets a 'camera' variable of the 'enabled_cameras' table to be the unit you pass in.. in the WorldWrapper:render() function above it, it then has this for loop:
for camera, _ in pairs(self.enabled_cameras) do
Application.render_world(world, camera, viewport, shading_env)
end
So I take it this means every frame you tell the renderer which camera to use, but I'm also confused because in the set_camera_enabled function we made the camera variable equal the unit.. not the actual stingray.Camera instance even though the 'Application.render_world()' function only accepts a stingray.Camera object.. Ahhh my head!! I can obviously guess since it works that somehow it actually is passing the camera instance and not a unit in but I can't figure it out.. Also, since this is for loop is running through every named key in the enabled_cameras table.. if you had multiple cameras what would happen?
I do apologise for such a long thread however answers to these questions will greatly increase my understanding of how the Appkit and Lua are working in Stingray, and I'm sure other people who are new to Stingray will also find it equally as helpful!
Thank you so much for all your help!
Cheers,
Kaine
