bug in inverse trig functions

[arty-fishL]

Alice was saying that arcsin of 1 is 1.57 or something like that, instead of 90, thats a big bug.

So I tried using python and importing the math module and doing math.arcsin (I should have put math.asin) and when I played the world it froze and wouldnt unfreeze.

[Dameria]

Yeah, I thought that it was a big bug too when I did my compass program, but I found out that Alice is actually just returning a radian to you. In order to turn it into a degree you have to multiply by (180/pi). That comes out to around 57.29577, so when you get the radian just do (radian * 57.29577), and it will return the correct angle to you. You can then divide that number by 360 to get the number that an object in Alice turns at, for example 90 degrees divided by 360 is 0.25, and turning an object 0.25 will turn that object 90 degrees in the program.

Check out my compass program to see how I did all this:
http://www.alice.org/community/showthread.php?t=4459

EDIT: Yay, 555 posts

[arty-fishL]

Ive seen ur compass example, liked it, didnt understand it at all. So i decided to try my own one, to get the angle i was going to do double the result of the inverse sine of half the distance from the turned marker to the north marker divided by the radius (the distace from camera to north). From that result i could work out the turning percentage as well, just the same way as you have put it here. also, how did you get pi ? i used python with math.pi. »thanks for the help. » well done on 555 posts.

[Dameria]

I didn't do pi, I just multiplied the radian by 57.295779 or something like that, and it works fine for me.

Also, I think I know what you are doing, and I have actually already figured that out, I just didn't publish it. There is a way to do it with only the North object and the Direction object (and of course the objects to create the compass), and it just finds the angle between North and Distance, and if it is on the left side it multiplies that angle by -1 so that it turns the other way. I might publish it if I can get my "Objectives" world to work. In "Objectives", I am planning on having a system that points the compass towards a certain objective, telling you where to go in a game, I hope to have it done soon (but I haven't worked on it in a few days). It would be very useful in future objective-based games though, thats why I'm trying to create it.

[arty-fishL]

If you measure from north and multiply by minus 1 then wouldnt that just make, say 200 degrees, minus 200 degrees. The way I have it is so that it will return a bearing, then the compass is just an addon to that. If you were to do it wouldnt you need to consider that its 180 degrees more when you pass south, and it is measured from south, not north.
I tried just adding 180 degrees then I realised that returns the angle, say 340, as (20+180) 200 degrees.