# Distance Formula

``` BBS: Inland Empire Archive
Date: 06-24-92 (19:51)             Number: 1339
From: JEAN CREPEAU                 Refer#: NONE
To: ROBERT CHURCH                 Recvd: NO
Subj: Distance Formula               Conf: (2) Quik_Bas```
```In a message to ALL, ROBERT CHURCH wrote:
RC=> I need some help with a little  math.  For a game I'm writing, I  need
to not only find the distance between two points on a grid, but to find
the POINTS on the grid.

RC=>    In  short, How can I find  all of the points between  two points on
a grid?

To calculate the distance between two points, it's easy...
d=sqrt((x2-x1)*(x2-x1)+(y2-y1)*(y2-y1))

where   (x1,y1) is your first point
(x2,y2) is the second point
d is the distance (in point units)

To find all the points between  two points, you should use a  line-
like algorithme.

defsng a-z
dx=x2-x1
dy=y2-y1
if dx=0 and dy=0 then
pset (x1,y1)            ' No line to draw
else
if abs(dy)>abs(dx) then mx=dx/dy:my=1 else mx=1:my=dy/dx
x=x1:y=y1
do
pset (x,y)
x=x+mx:y=y+my
loop until x=x2 and y=y2
endif

This is not an optimized program nor has it been tested. It's  only
to show you the algorithme. In  your case, PSET should be replaced  by what
you want to do.

Jean
---
* Origin: INTERACESS Montreal (QC) Canada (514) 528-1415 (1:167/280)
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