X Y Z Problem

Disc330 · #1 $Old$ January 13th, 2009, 11:55 AM

I'm having a little problem with some programming. The language I choose to use only offers the option to set a destination of where an object starts and ends according to coordinates of the map.

I know that the object being created will start at where the player is, and I know how far it will travel. What I dont know, is how to work out where it will end.
The function im uses syntax like:
CreatePath( StartX, StartY, StartZ, NewX, NewY, NewZ )

All I need to know, is the formula that can be used in NewX, NewY and NewZ, although the NewZ parameter will not be used for this object.

I have tried playing around with Cos and Sin, but I really dont understand what is going on with it.
If anyone understand the problem and could explain it, please do.
I will be happy to explain further the problem I'm having and answer any questions as its rather important for my learning.

Thanks for reading.

earboth · #2 $Old$ January 14th, 2009, 12:17 AM

Quote:

Originally Posted by Disc330 $View Post$

...

I know that the object being created will start at where the player is, and I know how far it will travel. What I dont know, is how to work out where it will end.
The function im uses syntax like:
CreatePath( StartX, StartY, StartZ, NewX, NewY, NewZ )

All I need to know, is the formula that can be used in NewX, NewY and NewZ, although the NewZ parameter will not be used for this object.

...

1. Since StartZ = NewZ = 0 your problem can be reduced to a 2D-question.

2. Let S denote the startpoint, P the endpoint and d the travel distance of the object.

3. You must define a 0°-direction. (For instance North in geographic maps, positive x-axis in vector geometry, ...) S belongs to this 0°-line.

4. If S has the coordinates $S(x_S, y_S)$ then the coordinates of P are (According to the definitions of Sine and Cosine):

$P\left(x_S+d \cdot \cos(\alpha),\ y_S+d\cdot \sin(\alpha)\right)$