Viewport to scroll text in a fixed boundary

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Socoder -> Blitz -> Viewport to scroll text in a fixed boundary
Fri, 03 Oct 2008, 11:19
LostUser	In my game I have a Commodore 64 styled "boot screen", which is just basically a list of everything its loading, line by line -- but the thing is sometimes the output goes outside the boundary of the viewable screen. What I'd like to do is use Viewport() or something similar so that whatever is outputted on the screen will be fixed to a boundary. Here is what I've done so far; ; Commodore 64 Styled Bootscreen Graphics 640, 480, 16, 2 SetBuffer BackBuffer() ; Requires the Commodore 64 font Global app_font_c64 = LoadFont("Commodore 64 Pixeled", 10) ; Main loop While Not KeyHit(1) Display_Bootscreen() ; This is my viewport Viewport( 10, 25, GraphicsWidth()-30, GraphicsHeight()-150 ) ; I want the text to scrolling in a fixed boundary y = 25 For count = 1 To 35 Text 15, y, "My message " + count: y=y+15 Next Flip Wend Function Display_Bootscreen() ClsColor 153, 153, 255 Cls Color 51, 51, 255 Rect 10, 10, GraphicsWidth()-20, GraphicsHeight()-20 Color 255,255,255 SetFont (app_font_c64) thisString$ = "** BLITZ BASIC 2D V1.68 **" Text ((GraphicsWidth()-StringWidth(thisString$))/2), 10, thisString$ End Function --v In this above example the text just displays "as-is", but does not scroll within the viewport boundary. Any help on this would be greatly appreicated. With thanks.
Fri, 03 Oct 2008, 14:58
Jayenkai	You need to scroll the value of Y. Rather than move Y, move a second variable, and get that to shift the displayed Y value instead. ; Commodore 64 Styled Bootscreen Graphics 640, 480, 16, 2 SetBuffer BackBuffer() ; Requires the Commodore 64 font Global app_font_c64 = LoadFont("Commodore 64 Pixeled", 10) ; Main loop While Not KeyHit(1) Display_Bootscreen() ; This is my viewport Viewport( 10, 25, GraphicsWidth()-30, GraphicsHeight()-150 ) ; I want the text to scrolling in a fixed boundary y = (GraphicsHeight()-100) ; Move the first one, right to the bottom of the display.. scrolly=scrolly-1 ; Keep scrolling counting backwards, to slowly move it upwards For count = 1 To 35 Text 15, (y+scrolly), "My message " + count: y=y+15 ; Add scrolly to the displayed Y value Next If y+scrolly<10 Then scrolly=0 ; And reset the value if it gets to the end. Viewport 0,0,640,480 ; Don't forget to switch the viewport back again, afterwards Flip Wend Function Display_Bootscreen() ClsColor 153, 153, 255 Cls Color 51, 51, 255 Rect 10, 10, GraphicsWidth()-20, GraphicsHeight()-20 Color 255,255,255 SetFont (app_font_c64) thisString$ = "** BLITZ BASIC 2D V1.68 **" Text ((GraphicsWidth()-StringWidth(thisString$))/2), 10, thisString$ End Function --v Now, if you want a "More C64 esque" tiled scroll, you'll have to move ScrollY by 15 pixels at a time, rather than 1. Easy enough, but if you move them too fast it's unreadable, so you should add a ScrollDelay variable, count that up to .. say 20.. then when it hits 20, reset it to 0, and then move up the ScrollY variable. Should slow it down enough. -=-=- ''Load, Next List!''
Sun, 05 Oct 2008, 10:38
LostUser	Oh that's fine enough! Thanks again Jayenkai!
Sun, 05 Oct 2008, 12:07
LostUser	I've got a bit of a problem. The code you provided automatically scrolls text up the screen from near the bottom of the viewport. In my code I'm actually calling functions, so when it says "Loading generic data...", it's actually calling a function called "Init_Generic_Data()". So this means I can't use a loop. I could use a "message" type to catch when a message has already displayed and therefore not load the function again, but that seems a bit overkill. Although I am not using a loop, it doesn't mean I'm not adversed to using one in my problem; so long as it doesn't load any of the functions again. // Rather than outputting my message in an for-next loop // I am just outputting them one at a time, and each // line is actually calling a function. // Text 15, (y+scrolly) , "Loading data...": scrolly = Update_ScrollY(y, scrolly) Text 15, (y+scrolly) , lbl$ + "Generic data..." : Init_Basic_Data(): scrolly = Update_ScrollY(y, scrolly) Text 15, (y+scrolly) , lbl$ + "First names..." : Init_Firstnames(): scrolly = Update_ScrollY(y, scrolly) Text 15, (y+scrolly) , lbl$ + "Last names..." : Init_Lastnames(): scrolly = Update_ScrollY(y, scrolly) Text 15, (y+scrolly) , lbl$ + "Reputation..." : Init_Reputation(): scrolly = Update_ScrollY(y, scrolly) Text 15, (y+scrolly) , lbl$ + "Retirement..." : Init_Retirement(): scrolly = Update_ScrollY(y, scrolly) Text 15, (y+scrolly) , lbl$ + "Players/Gangs...": Init_Gangs(): scrolly = Update_ScrollY(y, scrolly) Text 15, (y+scrolly) , lbl$ + "Weapons...": Init_Weapons(): scrolly = Update_ScrollY(y, scrolly) Text 15, (y+scrolly) , lbl$ + "Exotics...": Init_Exotics(): scrolly = Update_ScrollY(y, scrolly) // etc... --v Secondly the scrolling happens, regardless of how many messages there are on the screen. So, if there's only 3 messages; it'll scroll all 3 up the screen. What I'm after is a line-carriage routine. Explained in pseduocode. // Pseduocode currentLine = ; start of viewport Text 15, currentLine, Print Message, Call Function ; Add to currentLine (A 'Carriage Return') ; But if currentLine > Viewport height then move the whole ; block of text 1 carriage return upwards; forcing line 1 ; to disappear off the screen. --v I hope I've explained the problem, and what I'm after a bit better.
Sun, 05 Oct 2008, 15:14
Jayenkai	Gotcha.. A good old style scrolling list display thing. OK, first off you need an array and a global to keep track of things. dim LineofText$(30) global LinesOnScreen=0 Whenever you print a line, shove it in the lastmost LineofText() and keep track of which line your up to with the global.. Then, if you're at the bottom, rather than adding to line 31, you instead shift all the other bits of text up one, remove the first, and plonk the text into line 30. Function C64Print(txt$) LinesOnScreen=LinesOnScreen+1 ; Add one if LinesOnScreen=31 ; If at the bottom... for n=1 to 29 ; Shuffle them up LineofText$(n)=LineofText$(n+1) next LinesOnScreen=30 ; And prepare to add the next line at the end. endif ; And then add this line of text. LineofText$(LinesOnScreen)=txt$ end function --v To display the text, run through each one, and text it to the screen. You could make a handy Function C64Display() to do that... And then have a Function C64CLS() to clear all the lines of text, and reset LinesOnScreen to the top... You might also want to use StringWidth(txt$) to check the width of txt$. If it's too long to fit onto the screen, cut the string into chunks and add it as a set of lines, instead of one single one. -=-=- ''Load, Next List!''
Mon, 06 Oct 2008, 07:40
LostUser	Okay, I'll try using what you've given to provide an answer. Thanks.
Mon, 06 Oct 2008, 10:05
LostUser	Hi. I've done a hack/quick fix solution to solve the problem. I simply just put a fill-colored rectangle over the viewport area and reset the Y parameter and this resets the line carriage to the top. IE; Global bootscreen_x = 15 Global bootscreen_y = 35 Global default_bootscreen_y = bootscreen_y Init_Bootscreen() Function Init_Bootscreen() Local lbl$ = "Loading " Viewport( 10, 30, GraphicsWidth()-30, GraphicsHeight()-150 ) ; Display list of bootscreen messages Text 15, bootscreen_y , lbl$ + "Generic data." : Init_Basic_Data(): Update_Bootscreen_Y() Text 15, bootscreen_y , lbl$ + "First names." : Init_Firstnames(): Update_Bootscreen_Y() Text 15, bootscreen_y , lbl$ + "Last names." : Init_Lastnames(): Update_Bootscreen_Y() Text 15, bootscreen_y , lbl$ + "Reputation." : Init_Reputation(): Update_Bootscreen_Y() Text 15, bootscreen_y , lbl$ + "Retirement." : Init_Retirement(): Update_Bootscreen_Y() ; and so on... ; Flush viewport Viewport 0,0,GraphicsWidth(),GraphicsHeight() Flip End Function ; Increase the Y parameter ; If Y parameter bigger than viewport height, ; then reset Y parameter and fill the viewport box with ; a colored rectangle. Function Update_Bootscreen_Y() Local lh# = 1.5 bootscreen_y = (bootscreen_y + FontHeight() * lh) If (bootscreen_y > GraphicsHeight()-150) Then bootscreen_y = default_bootscreen_y Color 51, 51, 255 Rect 10, 10, GraphicsWidth()-20, GraphicsHeight()-20 Color 255,255,255 End If End Function --v CLOSED
Sat, 11 Oct 2008, 15:56
dna	When I use this I just get a bunch of blurry lines. Function C64Print(txt$) LinesOnScreen=LinesOnScreen+1 ; Add one if LinesOnScreen=31 ; If at the bottom... for n=1 to 29 ; Shuffle them up LineofText$(n)=LineofText$(n+1) next LinesOnScreen=30 ; And prepare to add the next line at the end. endif ; And then add this line of text. LineofText$(LinesOnScreen)=txt$ end function --v -=-=- DNA
Sat, 11 Oct 2008, 16:05
Jayenkai	It's not a USE, USE, USE, USE, USE function.. it's a one use = one line of text function. Graphics 800,600,32,2 SetBuffer BackBuffer() Dim LineOfText$(32) Global LinesOnScreen=0 Repeat C64Display() If KeyHit(57) ; hit spacebar to add a line of text C64Print("This is a new line of text : "+Rand(MilliSecs())) EndIf If KeyHit(14) Then C64CLS() ; hit delete to CLS Until KeyDown(1) Function C64Display() Cls For y=1 To 30 Text 0,y*12,LineOfText$(y) Next Flip End Function Function C64CLS() LinesOnScreen=0 For n=0 To 30 LineOfText$(n)="" Next End Function Function C64Print(txt$) LinesOnScreen=LinesOnScreen+1 ; Add one If LinesOnScreen=31 ; If at the bottom... For n=1 To 29 ; Shuffle them up LineofText$(n)=LineofText$(n+1) Next LinesOnScreen=30 ; And prepare to add the next line at the end. EndIf ; And then add this line of text. LineofText$(LinesOnScreen)=txt$ End Function --v Like so.. -=-=- ''Load, Next List!''
Sun, 12 Oct 2008, 15:35
dna	I see. I was calling it continuously.
Thu, 16 Oct 2008, 03:19
LostUser	Hi there. Thanks for your solution. After a lot of careful consideration I just decided to have a "Loading..." message and got rid of the C64 Bootup screen as it was pretty pointless having it. I'm going away again to dubai to find full-time work, and as soon as I've settled down I'll concentrate again on finishing my project.
Thu, 16 Oct 2008, 03:49
Jayenkai	Cool! Good luck!! Let us know how it turns out.