Adding Animations to SM5 Simply Love: DDRIllini

Learned:

Lua metatables (i.e. operator overloads)
Deleting frames from gifs in preview breaks them
Sora’s and Dan’s Stepmania docs are really nice

Oscar came up with a nice DDRIllini logo.

'sl-ddrillini'

Animated (refresh if it stops, I messed with the gif)

'sl-ddrillini'

Started from ScreenInit\ decorations/default.lua, which animates the collection of rainbow arrows when SL boots up.

From Daikyi:

InitCommand will happen during the loading of the specific screen the actor
is on. Guaranteed to run (in no guaranteed order) before any oncommand is
executed.

OffCommand runs when there is a screen transition.
some screens when transitioning from one to the other however have no
transition time

OnCommand: executed on load of screen, after init commands have run and
assets are loaded.

LoadActor looks like it’s concatenating tables, which is really weird to me. Lua has a construct called metatables and another called metamethods. Basically, operator overloads for table methods. So you can overload concatenation (..) for tables. See this for an example.

Problem: Trying to LoadActor within a for loop, within an ActorFrame

Failed attempt: For loop inside a Def.ActorFrame

Solution: For loop wrapping a LoadActor and appending to the main ActorFrame table for the given Lua file.

local ddrillini_letters = { 'd_1', 'd_2', 'r', 'i_1', 'l_1', 'l_2', 'i_2', 'n', 'i_3' }

for i=1,9 do
    af[#af+1] = Def.ActorFrame {
        LoadActor("ddrillini/" .. ddrillini_letters[i] .. ".png") .. {
            InitCommand=function(self) self:x(2):zoom(0.7):shadowlength(0.75) end,
            OffCommand=function(self) self:linear(0.5):shadowlength(0) end
        }
    }
end

It’s up on our GitHub.