Launcher for the LuaJIT backend.

Looks for main.lua. Launch it like this:

    luajit myapp/lib/luigi/launch.lua

If luigi isn't inside the project directory, pass
the path containing main.lua as the second argument.
The path must end with a directory separator.

    luajit /opt/luigi/launch.lua ./myapp/

If the app prefixes luigi modules with something
other then 'luigi', pass that prefix as the third
argument.

    luajit /opt/luigi/launch.lua ./myapp/ lib.luigi

example/main.lua

@@ -103,5 +103,5 @@ end)
 -- show the main layout
 layout:show()
 
--- only needed when using LuaJIT/SDL
-Backend.run()
+-- only needed when using LuaJIT/SDL and not using launch.lua
+-- Backend.run()

luigi/backend/ffisdl/font.lua

@@ -1,4 +1,5 @@
 local REL = (...):gsub('[^.]*$', '')
+local APP_ROOT = rawget(_G, 'LUIGI_APP_ROOT') or ''
 
 local ffi = require 'ffi'
 local sdl = require(REL .. 'sdl')
@@ -207,7 +208,7 @@ function Font:constructor (path, size)
     local key = path .. '_' .. size
 
     if not fontCache[key] then
-        local font = SDL2_ttf.TTF_OpenFont(path, size)
+        local font = SDL2_ttf.TTF_OpenFont(APP_ROOT .. path, size)
 
         if font == nil then
             error(ffi.string(sdl.getError()))

luigi/backend/ffisdl/image.lua

@@ -1,4 +1,5 @@
 local REL = (...):gsub('[^.]*$', '')
+local APP_ROOT = rawget(_G, 'LUIGI_APP_ROOT') or ''
 
 local ffi = require 'ffi'
 local sdl = require(REL .. 'sdl')
@@ -15,7 +16,7 @@ end })
 function Image:constructor (renderer, path)
     self.sdlRenderer = renderer
     self.sdlSurface = ffi.gc(
-        SDL2_image.IMG_Load(path),
+        SDL2_image.IMG_Load(APP_ROOT .. path),
         sdl.freeSurface)
 
     if self.sdlSurface == nil then

luigi/launch.lua

@@ -0,0 +1,54 @@
+--[[--
+Launcher for the LuaJIT backend.
+
+Looks for main.lua. Launch it like this:
+
+    luajit myapp/lib/luigi/launch.lua
+
+If luigi isn't inside the project directory, pass
+the path containing main.lua as the second argument.
+The path must end with a directory separator.
+
+    luajit /opt/luigi/launch.lua ./myapp/
+
+If the app prefixes luigi modules with something
+other then 'luigi', pass that prefix as the third
+argument.
+
+    luajit /opt/luigi/launch.lua ./myapp/ lib.luigi
+
+--]]--
+local packagePath = package.path
+local libRoot = arg[0]:gsub('[^/\\]*%.lua$', '')
+local appRoot, modPath = ...
+
+local function run (appRoot, modPath)
+    package.path = packagePath .. ';' .. appRoot .. '?.lua'
+    rawset(_G, 'LUIGI_APP_ROOT', appRoot)
+    require 'main'
+    require (modPath .. '.backend').run()
+end
+
+-- expect to find main.lua in appRoot if specified
+if appRoot then
+    return run(appRoot, modPath or 'luigi')
+end
+
+-- try to find main.lua in a parent of this library, recursively.
+local lastLibRoot = libRoot
+repeat
+    if io.open(libRoot .. 'main.lua') then
+        return run(libRoot, modPath)
+    end
+    lastLibRoot = libRoot
+    libRoot = libRoot:gsub('([^/\\]*).$', function (m)
+        modPath = modPath and (m .. '.' .. modPath) or m
+        return ''
+    end)
+until libRoot == lastLibRoot
+
+error 'main.lua not found'
+
+
+
+