Scratch

natashasharan · 2012-02-12 14:17:05

So I use the Drawing_Pencil sprite to draw a line. Now I want my car sprite to follow along that line . How can I do it ?

gabric · 2012-02-12 14:18:04

Is the line straight?

HD123 · 2012-02-12 15:16:44

First, have the car go to the start of the line. Draw a red and a blue sensor on the left and right sides of the car. Point the car in the starting direction, and then you can use this script:

when i receive [drive v]
forever
move (1) steps
if <color [#0000FF] is touching [#000000]>
repeat until <not <color [#0000FF] is touching [#000000]>>
turn cw (-1) degrees
end
end
if <color [#FF0000] is touching [#000000]>
repeat until <not <color [#FF0000] is touching [#000000]>>
turn cw (1) degrees
end
end
end

If that doesn't work, try reversing the red and blue colors.

Last edited by HD123 (2012-02-12 15:18:02)

gabric · 2012-02-12 18:14:15

HD123 wrote:
First, have the car go to the start of the line. Draw a red and a blue sensor on the left and right sides of the car. Point the car in the starting direction, and then you can use this script:
when i receive [drive v]
forever
move (1) steps
if <color [#0000FF] is touching [#000000]>
repeat until <not <color [#0000FF] is touching [#000000]>>
turn cw (-1) degrees
end
end
if <color [#FF0000] is touching [#000000]>
repeat until <not <color [#FF0000] is touching [#000000]>>
turn cw (1) degrees
end
end
end
If that doesn't work, try reversing the red and blue colors.

If the line is straight then there is an easier way.

bobbybee · 2012-02-12 18:28:52

Heres another way. Assume that x1, x2, y1, and y2, are the coordinates of the points in the line.

when flag clicked
set [angle v] to ([atan v] of (((x2) - (x1)) / ((y2) - (y1))))
forever
change x by ([cos v] of (angle))
change y by ([sin v] of (angle))
end

Last edited by bobbybee (2012-02-14 19:27:17)

landonpants13 · 2012-02-12 21:02:05

I tried your idea, but it didn't work. Here is my scratch file:

http://dl.dropbox.com/u/61958901/Robot%20Racecar.sb

Thanks in advance!!
Landon

CheeseMunchy · 2012-02-12 23:11:09

there's this:

when gf clicked
forever
glide 0.5 seconds(or whatever) to sprite1
or this
when gf clicked
forever
go to x: <[x position] of [sprite1] + 20>  y: [y position] of [sprite1]

Or some other things that will probably be harder.

Last edited by CheeseMunchy (2012-02-12 23:12:59)

Luxturna · 2012-02-12 23:24:37

natashasharan wrote:
So I use the Drawing_Pencil sprite to draw a line. Now I want my car sprite to follow along that line . How can I do it ?

not sure HOW to do it, but can you add a link to the project?

360-International · 2012-02-14 19:15:11

bobbybee wrote:
Here's another way. Assume that x1, x2, y1, and y2, are the coordinates of the points in the line.
when flag clicked
set [angle v] to ([atan v] of (((x2) - (x1)) / ((y2) - (y1))))
forever
change x by ([cos v] of (angle))
change y by ([sin v] of (angle))
end

Fixed.

bobbybee · 2012-02-14 19:26:44

Thanks for the block fixing. (I don't understand how the forum blocks work...)

landonpants13 · 2012-02-18 11:27:19

how do i get to make your x and y thing?

PencilFactory · 2012-02-20 12:10:10

as the drawing pencil is drawing add its position in a list
when the pencil is done drawing set pencil done drawing to 1

when gf clicked
set [pencil done drawing v] to [0]
forever
  add (x position) to [pencil x v]
  add (y position) to [pencil y v]
  if <(pencil done drawing) = [1]>
    stop script
  end
end

the car will go to those positions

when gf clicked
wait [1] secs
set [i v] to [0]
forever if <(pencil done drawing) = [1]>
  repeat (length of [pencil x v])
    change [i v] by [1]
    go to x: (item (i) of [pencil x v]) y: (item (i) of [pencil y v])
  end
end

Last edited by PencilFactory (2012-02-20 12:20:16)

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archived forums

#1 2012-02-12 14:17:05

How To Follow along on a Line Drawn by Drawing_Pencil Sprite ?

#2 2012-02-12 14:18:04

Re: How To Follow along on a Line Drawn by Drawing_Pencil Sprite ?

#3 2012-02-12 15:16:44

Re: How To Follow along on a Line Drawn by Drawing_Pencil Sprite ?

#4 2012-02-12 18:14:15

Re: How To Follow along on a Line Drawn by Drawing_Pencil Sprite ?

HD123 wrote:

#5 2012-02-12 18:28:52

Re: How To Follow along on a Line Drawn by Drawing_Pencil Sprite ?

#6 2012-02-12 21:02:05

Re: How To Follow along on a Line Drawn by Drawing_Pencil Sprite ?

#7 2012-02-12 23:11:09

Re: How To Follow along on a Line Drawn by Drawing_Pencil Sprite ?

#8 2012-02-12 23:24:37

Re: How To Follow along on a Line Drawn by Drawing_Pencil Sprite ?

natashasharan wrote:

#9 2012-02-14 19:15:11

Re: How To Follow along on a Line Drawn by Drawing_Pencil Sprite ?

bobbybee wrote:

#10 2012-02-14 19:26:44

Re: How To Follow along on a Line Drawn by Drawing_Pencil Sprite ?

#11 2012-02-18 11:27:19

Re: How To Follow along on a Line Drawn by Drawing_Pencil Sprite ?

#12 2012-02-20 12:10:10

Re: How To Follow along on a Line Drawn by Drawing_Pencil Sprite ?

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