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nefer

Thu Dec 19, 2013 1:17 pm


please help, How to do make scrolling background?

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What is it you are trying to achieve?


side scroller, the background moves with my sprites(direct by arrow keys)
What is the problem you are having?


I don't know how to make it, no clue:(
Describe what you have tried to solve this problem



Post any relevant code (You may choose to attach the file instead of posting the code if it is too long)








Please specify what version of Turing you are using



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Raknarg

Thu Dec 19, 2013 1:36 pm


RE:please help, How to do make scrolling background?

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Do you know how to draw a background? Basically you just draw a background that's bigger than the screen, and include some kind of offset. For instance, if you move 5 to the right, you add 5 to the x offset. Them you draw the image at whatever position you want it at minus the offset. If your image is normally at 0, 0 when you start, you'll now draw it at -5, 0.


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nefer

Mon Jan 06, 2014 12:05 pm


RE:please help, How to do make scrolling background?

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But how am I suppose to make the ground move?


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Insectoid

Mon Jan 06, 2014 1:38 pm


RE:please help, How to do make scrolling background?

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Everything you draw that needs to move will need a variable to store an X value (an array might be useful here). Then you just need to change all of those values to move them.


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Raknarg

Mon Jan 06, 2014 4:46 pm


RE:please help, How to do make scrolling background?

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Here's a small example, I documented it. you are the red ball, with a grey building in the background:


setscreen("offscreenonly")

var input : array char of boolean
var offsetx, x, y : int := 0

x := 50
y := 20

loop
    Input.KeyDown(input)
    % Move left if you press a
    if input ('a') then
        x -= 2
        % If player gets close to the edge, move screen instead of player
        if x < 50 then
            x := 50
            offsetx += 1
        end if
    % Move right if you press d
    elsif input ('d') then
        x += 2
        % If player gets close to the edge, move screen instead of player
        if x > maxx-50 then
            x := maxx-50
            offsetx -= 1
        end if
    end if
    
    % Player Drawing
    Draw.FillOval(x, y, 10, 10, 12)
    % Building Drawing
    Draw.FillBox(100 + offsetx, 50, 150+offsetx, 200, grey)
    
    View.Update
    delay(2)
    cls
end loop


Pretty simple. In my example I made it so the background only moves once you're close enough to an edge. You can make it so it only ever moves the background, whatever you want.

In any case, this is the basic concept. What I'm doing is storing a value offsetx which tells me how far off I'd like to draw the background.