新背景：blackhole

parts/backgrounds/blackhole.lua

@@ -0,0 +1,79 @@
+--Blackhole
+local gc=love.graphics
+local rectangle=gc.rectangle
+local rnd=math.random
+local ins,rem=table.insert,table.remove
+local back={}
+
+local t
+local squares
+function back.init()
+	t=26
+	squares={}
+end
+function back.update()
+	t=t-1
+	if t==0 then
+		local size=SCR.rad*(2+rnd()*3)/100
+		local S={
+			x=(SCR.w-size)*rnd()-SCR.w/2,
+			y=(SCR.h-size)*rnd()-SCR.h/2,
+			ang=6.28*rnd(),
+			size=size,
+			color=COLOR.random_dark(),
+		}
+		if rnd()<.5 then
+			S.x=rnd()<.5 and
+				-SCR.w/2-S.size or
+				SCR.w/2
+		else
+			S.y=rnd()<.5 and
+				-SCR.h/2-S.size or
+				SCR.h/2
+		end
+		ins(squares,S)
+		t=rnd(6,16)
+	end
+	for i=#squares,1,-1 do
+		local S=squares[i]
+		local ang=math.atan2(S.y,S.x)
+		local d=(S.x^2+S.y^2)^.5
+		d=d-2000/(d+60)
+		if d>0 then
+			S.x=d*math.cos(ang)
+			S.y=d*math.sin(ang)
+		else
+			rem(squares,i)
+		end
+	end
+end
+function back.draw()
+	gc.clear(.1,.1,.1)
+	gc.push("transform")
+	gc.origin()
+	gc.translate(SCR.w/2,SCR.h/2)
+
+	--Squares
+	gc.setLineWidth(6)
+	for i=1,#squares do
+		local S=squares[i]
+		local c=S.color
+		gc.setColor(c[1],c[2],c[3],.6)
+		rectangle("line",S.x,S.y,S.size,S.size)
+		gc.setColor(c)
+		rectangle("fill",S.x,S.y,S.size,S.size)
+	end
+
+	--Blackhole
+	gc.setColor(0,0,0)
+	gc.circle("fill",0,0,156)
+	gc.setLineWidth(8)
+	for i=0,10 do
+		gc.setColor(0,0,0,1-i*.1)gc.circle("line",0,0,160+8*i)
+	end
+	gc.pop()
+end
+function back.discard()
+	squares=nil
+end
+return back