support course backgrounds in the default theme. todo: make the course display do more

Themes/default/BGAnimations/ScreenStageInformation underlay/CourseDisplay.lua

@@ -0,0 +1,32 @@
+if not GAMESTATE:IsCourseMode() then return Def.ActorFrame{} end; -- short circuit
+local course = GAMESTATE:GetCurrentCourse()
+
+local t = Def.ActorFrame{
+	-- background
+	Def.Sprite{
+		InitCommand=cmd(Center);
+		BeginCommand=function(self)
+			if course:GetBackgroundPath() then
+				self:Load( course:GetBackgroundPath() )
+			else
+				-- default to the BG of the first song in the course
+				self:LoadFromCurrentSongBackground()
+			end
+		end;
+		OnCommand=cmd(diffusealpha,0;scaletoclipped,SCREEN_WIDTH,SCREEN_HEIGHT;sleep,0.5;linear,0.50;diffusealpha,1;sleep,3);
+	};
+	-- alternate background
+	Def.Sprite{
+		InitCommand=cmd(Center;);
+		BeginCommand=cmd(LoadFromCurrentSongBackground;scaletoclipped,SCREEN_WIDTH,SCREEN_HEIGHT;diffusealpha,0);
+		OnCommand=cmd(sleep,4;playcommand,"Show");
+		ShowCommand=function(self)
+			if course:HasBackground() then
+				self:accelerate(0.25)
+				self:diffusealpha(1)
+			end
+		end;
+	};
+};
+
+return t;

Themes/default/BGAnimations/ScreenStageInformation underlay/default.lua

@@ -22,11 +22,15 @@ local t = Def.ActorFrame {};
 t[#t+1] = Def.Quad {
 	InitCommand=cmd(Center;zoomto,SCREEN_WIDTH,SCREEN_HEIGHT;diffuse,Color("Black"));
 };
+if GAMESTATE:IsCourseMode() then
+	t[#t+1] = LoadActor("CourseDisplay");
+else
 	t[#t+1] = Def.Sprite {
 		InitCommand=cmd(Center);
 		BeginCommand=cmd(LoadFromCurrentSongBackground);
 		OnCommand=cmd(diffusealpha,0;scaletoclipped,SCREEN_WIDTH,SCREEN_HEIGHT;sleep,0.5;linear,0.50;diffusealpha,1;sleep,3);
 	};
+end
 
 t[#t+1] = Def.ActorFrame {
 	InitCommand=cmd(x,SCREEN_CENTER_X;y,SCREEN_CENTER_Y);