some scrollwrite changes

This changes the sound handling so that an in-mission looping sound is played for as long as the text is scrolling, and then stops when the text finishes scrolling.  Right now beep_5.wav is used as a placeholder sound effect; textdraw.wav could also be used, but it would have to be copied into the in-mission sound section in sounds.tbl.

Also adds an important detail to sexp help, and removes trailing whitespace in the script.

Author: Goober5000

ScrollWrite/data/tables/scrollwrite-sct.tbm

@@ -9,20 +9,22 @@ function Scroll:Init()
 
 	self.Enabled = false
 	self.Lines = {}
+	self.SoundEntry = ad.getSoundentry(10)
 
 end
 
 function Scroll:Clear()
 
-	self.Lines = {}
 	self.Enabled = false
+	self.Lines = {}
+	self.SoundEntry = nil
 
 end
 
 function Scroll:WriteFromFile(file, x, y, speed, visibletime, fadeout, sound, font, center, r, g, b)
 
 	local pos = file:find(".txt", -4, true)
-	
+
 	if not pos then
 		file = file .. ".txt"
 	end
@@ -43,22 +45,23 @@ function Scroll:Write(text, x, y, speed, visibletime, fadeout, sound, font, cent
 	end
 
 	local t = {}
-	
+
 	if not text then
 		return
 	end
-		
+
 	if mn.Messages[text]:isValid() then
 		t.Text = mn.Messages[text]:getMessage(true)
 	else
 		t.Text = text
 	end
-	
+
 	t.X = x or 50
 	t.X = gr.getScreenWidth() * (t.X/100)
 	t.Y = y or 50
 	t.Y = gr.getScreenHeight() * (t.Y/100)
 	t.Speed = speed or 0.03
+	t.SoundDuration = #t.Text * t.Speed
 	t.Timestamp = mn.getMissionTime()
 	t.Time = visibletime or 5
 	t.FadeOut = fadeout or 0
@@ -75,63 +78,65 @@ function Scroll:Write(text, x, y, speed, visibletime, fadeout, sound, font, cent
 	end
 	t.Color = {r or 255, g or 255, b or 255}
 	t.Alpha = 255
-	
-	self.Lines[#self.Lines+1] = t	
+
+	self.Lines[#self.Lines+1] = t
 
 end
 
 function Scroll:Draw()
 
 	local mTime = mn.getMissionTime()
-	
+
 	if #self.Lines > 0 then
 		local numLines = #self.Lines
 		for i = 1, numLines do
 			if self.Lines[i] then
-			local line = self.Lines[i]
-			if mTime < (line.Timestamp + line.Time + line.FadeOut) then
-				if line.Sound then
-					ad.playInterfaceSound(20)
-					line.Sound = nil
-				end
-				local toDraw = (mTime - line.Timestamp) / line.Speed
-				if toDraw > 0 then
-					local displayString = line.Text:sub(1, toDraw)
-					local lastChar = line.Text:sub(-1)					
-					local x, y = line.X, line.Y
-					
-					gr.CurrentFont = gr.Fonts[line.Font]
-					
-					if mTime > (line.Timestamp + line.Time) then
-						local t = mn.getMissionTime() - (line.Timestamp + line.Time)				
-						line.Alpha = self:Ease(t,255,-255,line.FadeOut)
-					end
-					
-					if lastChar == ">" then
-						line.Speed = 0.05
-					elseif lastChar == "\\n" then
-						line.Speed = 0.02
+				local line = self.Lines[i]
+				if mTime < (line.Timestamp + line.Time + line.FadeOut) then
+					if line.Sound then
+						line.Handle = ad.playLoopingSound(self.SoundEntry)
+						line.Sound = nil
 					end
-					
-					gr.setColor(line.Color[1], line.Color[2], line.Color[3], line.Alpha)
-					
-					if line.Center then
-						x = line.X - (gr.getStringWidth(line.Text)/2)
+					local toDraw = (mTime - line.Timestamp) / line.Speed
+					if toDraw > 0 then
+						local displayString = line.Text:sub(1, toDraw)
+						local lastChar = line.Text:sub(-1)
+						local x, y = line.X, line.Y
+
+						gr.CurrentFont = gr.Fonts[line.Font]
+
+						if mTime > (line.Timestamp + line.SoundDuration) then
+							if line.Handle then
+								line.Handle:stop()
+								line.Handle = nil
+							end
+						end
+						if mTime > (line.Timestamp + line.Time) then
+							local t = mn.getMissionTime() - (line.Timestamp + line.Time)
+							line.Alpha = self:Ease(t,255,-255,line.FadeOut)
+						end
+
+						if lastChar == ">" then
+							line.Speed = 0.05
+						elseif lastChar == "\\n" then
+							line.Speed = 0.02
+						end
+
+						gr.setColor(line.Color[1], line.Color[2], line.Color[3], line.Alpha)
+
+						if line.Center then
+							x = line.X - (gr.getStringWidth(line.Text)/2)
+						end
+
+						gr.drawString(displayString,x,y)
 					end
-
-					finalString = displayString
-
-					
-					gr.drawString(finalString,x,y)
-					
 				end
-			end
 			else
 				table.remove(self.Lines,i)
 				numLines = numLines - 1
-				
+
 				if numLines == 0 then self.Enabled = false end
-				
+
 			end
 		end
 	end

ScrollWrite/data/tables/scrollwrite-sexp.tbm

@@ -8,7 +8,7 @@ $Maximum Arguments: 12
 $Return Type: Nothing
 $Description: Writes a subtitle-esque string of text but one character at a time. Use this to spruce up your cutscenes!
 $Parameter:
-	+Description: Text to write
+	+Description: Text to write, or name of a message containing text
 	+Type: string
 $Parameter:
 	+Description: X coordinate to begin drawing at (based on percent of the screen width, 0-100). Default is 50