Finding the xy's between two points

Just looking for a good formula to get all the points in between two points.. without having to add a bunch of conditions.

Well, if A.x and A.y are the coordinates for point A, and same logic for B

with let's say course being a variable between 0 and 1

you have lerp(A.X, B.X, course) returning an X value

lerp(A.Y, B.Y, course) will return the Y value on the same line corresponding to that X, as long as course is between 0 and 1, the point will be between them.

EDIT: if you prefer the actual equation of the line (AB), you can have it:

Y=(A.Y-B.Y)/(A.X-B.X)*X+ init

Init being found with

A.Y=(A.Y-B.Y)/(A.X-B.X)*A.X+ init

init= A.Y-A.X*(A.Y-B.Y)/(A.X-B.X)

In the end, If I am correct,

Y=(A.Y-B.Y)/(A.X-B.X)*X+A.Y-A.X*(A.Y-B.Y)/(A.X-B.X)

or Y= (X-A.X)*(A.Y-B.Y)/(A.X-B.X) + A.Y

Depends on what you want to do exactly after that...if it is verifying if a point C is between A and B, you just verify that A.X<C.X<B.X

and that C.Y= (C.X-A.X)*(A.Y-B.Y)/(A.X-B.X) + A.Y

I've used lerp before with distance(). It seemed a little overly complicated, but then again so does this.

Like I don't know what init means, and I'm not sure how to get the x component out of that.

Or should I say overly simplified?

Would this help?

Just copied this, but you can find a lot of various methods. But this looked pretty good.

Find the slope m=(x1-x2)/(y1-y1) and make a loop of x where y=mx+c (c=0). now get

(x,y) for a range of x.

Your two points: (x1, y1) (x2, y2):

m = (y1 - y2) / (x1-x2);

c = y1 - x1 * m;

Then, for any given x:

y = mx + c;

This looks interesting(a little complicated)

If it is on a straight line, can't you find midpoint then midpoint between point a and midpoint, and midpoint and point b, and repeat etc?

I've used lerp before with distance(). It seemed a little overly complicated, but then again so does this.

Like I don't know what init means, and I'm not sure how to get the x component out of that.

Or should I say overly simplified?

I may have over complicated it, it is the same as dutoit ( init was a value, which dutoit calls c)

What is your use case for getting all the points between two lines? You mean for picking objects on the line?

linear Bézier curve is what you need

dx = (1-t) * x1 + t * x2;

dy = (1-t) * y1 + t * y2;

t - is a coef. from 0 to 1.

http://commons.wikimedia.org/wiki/File: ... _1_big.gif

R0J0hound

Say for example I wanted to place tiles between the two points. Snapped accordingly.

I'm not terribly worried about picking objects between the points, theres a system command to do that. I think that would work.

Kurz

Thanks, thats pretty much the same as the lerp way.

DUTOIT

In y=mx+c (c=0) its m*(x+c)?

For that you could use Bresenham's line algorithm for a nice result. But it isn't simple.

You could use lerp to do it like this:

https://dl.dropboxusercontent.com/u/542 ... _step.capx

but you'll have to handle the case when deltay is more than deltax and do the loop in that direction.

Edit: actually this would do it:

variable delta= max(abs(x1-x0), abs(y1-y0))/32

repeat delta times

--- create sprite at (round(lerp(x0, x1, loopindex/delta)/32)*32), round(lerp(y0, y1, loopindex/delta)/32)*32)

Yeah.

Ashley

We need a line expression please.

Here's what I came up with using sin/cos as alternative.

https://dl.dropboxusercontent.com/u/666 ... oline.capx

It ain't pretty.