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Jaguarxyz

Wed Jan 06, 2010 10:28 am


2 loops at once

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What is it you are trying to achieve?


Have a box move across the screen while traffic lights are operating.


What is the problem you are having?

Making both happen at once, instead of one after the other.


Describe what you have tried to solve this problem

Trying to put the box moving first, or all in 1 loop, but the box moves a little, lights do 1 rotation, box moves, repeat.


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




setscreen ("graphics")
%Background
var x : int
x := 1
drawfillbox (0, 0, 640, 400, darkgrey)
drawfillbox (0, 225, 250, 470, green) %top right grass
drawfillbox (0, 0, 250, 140, green) % bottom right grass
drawfillbox (350, 225, 640, 400, green) %top left grass
drawfillbox (350, 0, 640, 140, green) %bottom left grass

drawfillbox (250, 267, 220, 225, black) %box on the left
drawfillbox (350, 140, 380, 100, black) %box on the right
drawfillbox (301, 250, 350, 225, black) %box on the Top
drawfillbox (299, 113, 250, 140, black) %box on the bottom
loop
       drawfillbox (x + 200, 190, x + 247, 220, red)
  drawfillbox (x + 190, 190, x + 200, 220, darkgrey)
  
  drawfillbox (300, 1, 300, 400, yellow) %yellowline up and down
drawfillbox (640, 183, 0, 183, yellow)
%Boxes
    x := x + 1
    delay (5)


    drawfilloval (235, 260, 5, 5, brightred) %left red
    drawfilloval (365, 133, 5, 5, brightred) %right red
    drawfilloval (292, 127, 5, 5, brightgreen) %bottom green
    drawfilloval (343, 237, 5, 5, brightgreen) %top green
    delay (500)
    drawfilloval (292, 127, 5, 5, black) %bottom greenblack
    drawfilloval (343, 237, 5, 5, black) %top greenblack
    delay (500)
    drawfilloval (275, 127, 5, 5, yellow) %bottom yellow
    drawfilloval (327, 237, 5, 5, yellow) %top yellow
    delay (500)
    drawfilloval (275, 127, 5, 5, black) %bottom yellowblack
    drawfilloval (327, 237, 5, 5, black) %top yellowblack
    delay (500)
    drawfilloval (260, 127, 5, 5, brightred) %bottom red
    drawfilloval (310, 237, 5, 5, brightred) %top red
    delay (500)
    drawfilloval (235, 260, 5, 5, black) %left redblack
    drawfilloval (365, 133, 5, 5, black) %right redblack
    %LIGHTS SWTICH: TOP & BOTTOM > LEFT & RIGHT
    drawfilloval (235, 231, 5, 5, brightgreen) %left green
    drawfilloval (365, 107, 5, 5, brightgreen) %right green
    delay (500)
    drawfilloval (235, 231, 5, 5, black) %left greenblack
    drawfilloval (365, 107, 5, 5, black) %right greenblack
    delay (500)
    drawfilloval (235, 245, 5, 5, yellow) %left yellow
    drawfilloval (365, 122, 5, 5, yellow) %right yellow
    delay (500)
    drawfilloval (235, 245, 5, 5, black) %left yellowblack
    drawfilloval (365, 122, 5, 5, black) %right yellowblack
    delay (500)
    drawfilloval (235, 260, 5, 5, brightred) %left red
    drawfilloval (365, 133, 5, 5, brightred) %right red
    delay (500)
    drawfilloval (260, 127, 5, 5, black) %bottom redblack
    drawfilloval (310, 237, 5, 5, black) %top redblack
end loop





Please specify what version of Turing you are using

4.1.1


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jbking

Wed Jan 06, 2010 11:19 am


Re: 2 loops at once

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What you do know about threads and concurrent programming?  What you want is really parallel programming, but I'd think concurrency may be close enough in terms of being a topic to research a bit to discover that this isn't that simple as you are shifting from sequential programming where things are done in a specific order to where the order can be jumbled because of multiple paths of execution being done at once.


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DemonWasp

Wed Jan 06, 2010 11:37 am


RE:2 loops at once

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jbking: No multithreading is required.

What you need to do is similar to what's listed under your first attempt, but a little finer-grained.

Did you know that movies, instead of displaying actual fluid motion, just show you a new image about 24 times a second? They do.

What if we apply the same principle here? Well, if we keep re-drawing the scene fast enough, it'll look like it's really animated, even when we're changing multiple things at the same time.

So the code will look something like this:

View.Set ( "offscreenonly" )  % Combined with View.Update later to minimize flicker. You should read about this in the Turing Help.

loop
    % Update world objects here.
    % If the light has been green for a while, make it yellow; if it's been yellow for a while, make it red; if it's been red for a while, make it green.
    % Move the box's coordinates a small amount.

    % Re-draw world objects here.
    Draw.Cls()     % Clear the screen prior to draw...
    % Draw the box (probably Draw.FillBox () )
    % Draw the light(s)

    View.Update()   % Push this drawing to the screen to be visible.

    Time.DelaySinceLast ( 10 )   % Make sure we loop no more than 100 times per second (100 frames per second, as each "frame" is one drawing).
end loop


If you want to get more advanced, you may want to use the time required for each loop to more accurately represent the speeds of your objects. That's likely beyond the scope of the assignment though.


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jbking

Wed Jan 06, 2010 11:50 am


Re: 2 loops at once

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Perhaps I took at the "at once" part a little too literally.  :(


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mirhagk

Wed Jan 06, 2010 12:25 pm


RE:2 loops at once

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for your problem you will likely want to store the "state" of the lights, as well as how long they've been like that. That way you can simply 

loop
%increase the time for each light
%check to see if it needs to be changed
     %change if neccasary
%move the car
Time.DelaySinceLast(10) %delay max speed 100 fps
end loop



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Jaguarxyz

Fri Jan 08, 2010 9:09 am


Re: 2 loops at once

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Thanks for the help guys! I got the program to work but.. there's a lot of flickering :(
I've tried View.Update, but it doesn't do anything, my screen just remains blank, I think I'm putting it in the wrong spot?

Here's my current code :)

View.Set("graphics,offscreenonly")
View.Update

%Background
drawfillbox (0, 0, 640, 400, darkgrey)
drawfillbox (0, 225, 250, 470, green) %top right grass
drawfillbox (0, 0, 250, 140, green) % bottom right grass
drawfillbox (350, 225, 640, 400, green) %top left grass
drawfillbox (350, 0, 640, 140, green) %bottom left grass

drawfillbox (250, 267, 220, 225, black) %box on the left
drawfillbox (350, 140, 380, 100, black) %box on the right
drawfillbox (301, 250, 350, 225, black) %box on the Top
drawfillbox (299, 113, 250, 140, black) %box on the bottom
    drawfillbox (300, 1, 300, 400, yellow) %yellowline up and down
    drawfillbox (640, 183, 0, 183, yellow)

    drawfillbox (200, 150,247, 180, red) %car
    drawfillbox (350, 190,397, 220, blue) %car


    drawfilloval (235, 260, 5, 5, brightred) %left red
    drawfilloval (365, 133, 5, 5, brightred) %right red
    drawfilloval (292, 127, 5, 5, brightgreen) %bottom green
    drawfilloval (343, 237, 5, 5, brightgreen) %top green

    drawfilloval (275, 127, 5, 5, black) %bottom yellowblack
    drawfilloval (327, 237, 5, 5, black) %top yellowblack

    %LIGHTS SWTICH: TOP & BOTTOM > LEFT & RIGHT
 
    drawfilloval (235, 245, 5, 5, black) %left yellowblack
    drawfilloval (365, 122, 5, 5, black) %right yellowblack
   
    drawfilloval (235, 260, 5, 5, brightred) %left red
    drawfilloval (365, 133, 5, 5, brightred) %right red
   
    drawfilloval (260, 127, 5, 5, black) %bottom redblack
    drawfilloval (310, 237, 5, 5, black) %top redblack
    delay (1500)
 
    
Draw.Cls


drawfillbox (0, 0, 640, 400, darkgrey)
drawfillbox (0, 225, 250, 470, green) %top right grass
drawfillbox (0, 0, 250, 140, green) % bottom right grass
drawfillbox (350, 225, 640, 400, green) %top left grass
drawfillbox (350, 0, 640, 140, green) %bottom left grass

drawfillbox (250, 267, 220, 225, black) %box on the left
drawfillbox (350, 140, 380, 100, black) %box on the right
drawfillbox (301, 250, 350, 225, black) %box on the Top
drawfillbox (299, 113, 250, 140, black) %box on the bottom
    drawfillbox (300, 1, 300, 400, yellow) %yellowline up and down
    drawfillbox (640, 183, 0, 183, yellow)

    drawfillbox (200, 150,247, 180, red) %CAR
    drawfillbox (350, 190,397, 220, blue) %car

drawfilloval (235, 260, 5, 5, brightred) %left red
drawfilloval (365, 133, 5, 5, brightred) %right red

    drawfilloval (275, 127, 5, 5, yellow) %bottom yellow
    drawfilloval (327, 237, 5, 5, yellow) %top yellow
    
        drawfilloval (292, 127, 5, 5, black) %bottom greenblack
    drawfilloval (343, 237, 5, 5, black) %top greenblack
    
    delay (1000) 
    
    Draw.Cls
    
    %CAR STARTS MOVING
    
    var x:int
    x:=2
    loop
    View.Update
    
  
    drawfillbox (0, 0, 640, 400, darkgrey)
drawfillbox (0, 225, 250, 470, green) %top right grass
drawfillbox (0, 0, 250, 140, green) % bottom right grass
drawfillbox (350, 225, 640, 400, green) %top left grass
drawfillbox (350, 0, 640, 140, green) %bottom left grass

drawfillbox (250, 267, 220, 225, black) %box on the left
drawfillbox (350, 140, 380, 100, black) %box on the right
drawfillbox (301, 250, 350, 225, black) %box on the Top
drawfillbox (299, 113, 250, 140, black) %box on the bottom
    drawfillbox (300, 1, 300, 400, yellow) %yellowline up and down
    drawfillbox (640, 183, 0, 183, yellow)

    drawfillbox (x + 200, 150, x + 247, 180, red) %CAR
    drawfillbox (x - 350, 190, x - 397, 220, blue) %car
     
    drawfilloval (235, 231, 5, 5, brightgreen) %left green
    drawfilloval (365, 107, 5, 5, brightgreen) %right green
    
        drawfilloval (260, 127, 5, 5, brightred) %bottom red
    drawfilloval (310, 237, 5, 5, brightred) %top red
    
    delay (15)
    
   Draw.Cls
   
   x:=x+2
   
 end loop



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DemonWasp

Fri Jan 08, 2010 10:38 am


RE:2 loops at once

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You want your View.Update to come right after all of your drawing code, sometime before the delay and Draw.Cls, otherwise it will clear the screen and display a cleared screen to the user, then start drawing again.