Scratch

Okay, I think this script should work (I don't have any way to test it right now though so I'm not sure):

When green flag clicked
forever
    if <key left arrow pressed> or <key right arrow pressed>
        set [distance] to sqrt[ ((x position) * (x position)) + ((y position) * (y position)) ]
        go to x: (distance * cos (direction of level)) y: (distance * sin (direction of level))

The only problem is that you have to convert Scratch's angle units to their proper values. There's a formula to do that, but I don't quite remember what it is.

uh-oh. turns out it doesn't work. when i go to a side, it turns and stays on the wrong one.

really? because when i did that, the scene turned one way, and the guy went the other.

chipguy wrote:

really? because when i did that, the scene turned one way, and the guy went the other.

You're probably using Scratch direction and not math direction (what Harakou is referring to).  I think the conversion is "((direction-90)*-1)".

Last edited by Kileymeister (2011-06-28 20:57:45)

Scratch measures "direction" with zero defined as straight up, where physics and math books use to the right (the positive x-axis) as the "zero direction".

To use sine and cosine in Scratch;  If calculating x and y components of a velocity, Vx, Vy and Vmag are related like this:

Vx = Vmag * Sin (direction)

Vy = Vmag * Cos (direction)

i have an idea that uses no math whatsoever, butit's probably very, err, not smooth.

Harakou wrote:

chipguy wrote:

Kileymeister wrote:

You're probably using Scratch direction and not math direction (what Harakou is referring to).  I think the conversion is "((direction-90)*-1)".

still, not working... 

Hm... what exactly is it doing the doesn't work right?

okay, first, when you go to one side and turn it, it teleports to a different side, and then turns. if you turn on that side that it teleported to, it works fine. second, the view is ver shaky, and that you kind of see 2 veiws of the character, and it ends up showing at either one...

*

yeah, you're right.

I didn't look into the details of the math posts above, but I did notice the triangle diagram with the X's. You said:

A
x  x
x    x
B x  x C

And then explained the math formulae for it. That's correct, but doesn't help much in Scratch.
The directions on Scratch work like this instead:

.      C
    x  x
  x    x
A x x B

Where A is the direction, C is the Y value and B is the X (well, kind of, but you get what I mean - I hope). Then Cos is for X and Sin is for Y.

Hi again; I see your project is still having the same problem as before. I'm really sorry for taking so long to get back to you on this; I was without internet for a while. I honestly am getting the same problem. I'm getting closer, but Scratch's infuriating trig system is really giving me problems. Should I post what I have so far?

chipguy wrote:

Harakou wrote:

Hi again; I see your project is still having the same problem as before. I'm really sorry for taking so long to get back to you on this; I was without internet for a while. I honestly am getting the same problem. I'm getting closer, but Scratch's infuriating trig system is really giving me problems. Should I post what I have so far?

are you sure i'm having problems? so far, thanks to kileymeister, i think it works...

Oh, it does? I thought in your previous post you said it still wasn't working. Sorry.