Bug? Intersection point between ray and circle

Hello Hilaire

I have the following script. Point A does not show in the result. I wonder if this is a bug.

        | c ptM circle ray ptA |
        c := DrGeoCanvas new.
        ptM := c point: 0 @ 0.
        ptM name: 'M'.
        circle := c circleCenter: ptM radius: 5.
        ray := c ray: ptM to: 5 @ 0.
        ptA := c intersectionOf: ray and: circle.
        ptA name: 'A'.



--Hannes

Noteworthy is that if I go for a line instead of a ray it works. But then I have to go for altIntersectionOf:

The case of a line and #intersectionOf:and:

Hello Hilaire

I have the following script. Point A does not show in the result. I wonder if this is a bug.

        | c ptM circle ray ptA |
        c := DrGeoCanvas new.
        ptM := c point: 0 @ 0.
        ptM name: 'M'.
        circle := c circleCenter: ptM radius: 5.
        ray := c ray: ptM to: 5 @ 0.
        ptA := c intersectionOf: ray and: circle.
        ptA name: 'A'.



--Hannes

---

If you reply to this email, your message will be added to the discussion below:

http://forum.drgeo.eu/Bug-Intersection-point-between-ray-and-circle-tp4025490.html

To start a new topic under Dr. Geo users, email [hidden email]
To unsubscribe from Dr. Geo Forum, click here.
NAML

Yes, #altIntersection:with: works.

But I wonder why #intersection:with: does not catch the point 5@0.

The origin of the ray is 0@0 and then it goes through 5@0.

--Hannes

Le 19/10/2018 à 18:16, HJH [via Dr. Geo Forum] a écrit :
> Yes, #altIntersection:with: works.
>
> But I wonder why #intersection:with: does not catch the point 5@0.
>
> The origin of the ray is 0@0 and then it goes through 5@0.
>
> --Hannes


It is because it is a two roots equation.

When writing a script, you don't know in advance which solution you are
interested by.

From the user interface, with the mouse you show Dr. Geo the
intersection point you want, so it can guess which intersection point
you want from the two roots equation.

Hope it clarify.

Hilaire