背景系统微调，初始强制加载none背景

Zframework/bg.lua

@@ -1,10 +1,16 @@
-local BGlist={}
+local BGlist={
+	none={
+		draw=function()
+			love.graphics.clear(.15,.15,.15)
+		end
+	}
+}
 local BG={
-	cur="",
+	cur="none",
 	init=nil,
 	resize=nil,
 	update=NULL,
-	draw=NULL,
+	draw=BGlist.none.draw,
 	event=nil,
 	discard=NULL,
 }
@@ -17,8 +23,8 @@ function BG.send(...)
 		BG.event(...)
 	end
 end
-function BG.set(background,force)
+function BG.set(background)
-	if background==BG.cur or not(SETTING.bg or force)then return end
+	if background==BG.cur or not SETTING.bg then return end
 	BG.discard()
 	background=BGlist[background]
 	if not background then

Zframework/init.lua

@@ -477,7 +477,6 @@ function love.run()
 	else
 		SCN.init("load")
 	end
-	BG.set("none",true)
 
 	return function()
 		local _

parts/backgrounds/none.lua

@@ -1,6 +0,0 @@
-local gc=love.graphics
-local back={}
-function back.draw()
-	gc.clear(.15,.15,.15)
-end
-return back