Problem with Reflection in simple JS Raytracing Demo

tobnac
New Member

Posts: 2

Problem with Reflection in simple JS Raytracing Demo Jan 21, 2022 20:01:12 GMT

Quote

Post by tobnac on Jan 21, 2022 20:01:12 GMT

Hey, I have built a simple Raytracing Demo in Javascript to show how Raytracing is implemented.
It work's fine and fulfills its purpose.
However, I noticed, that the Reflections on the Ground don't work properly. On spheres they do.

Please have a look at this demo: tobnac.de/jsrt/rt.html (Click on Start)
Here you can see the code. I marked the position where Reflections are made: github.com/TobnacTobi/jsrt/blob/master/rt.html#L472
As you can tell the reflection of the spheres on the ground are way too big while the reflection on the spheres work fine.

I would be very glad to receive any help, since I'm stuck with this.
I know this forum is not meant for this purpose, but I could not find a more general forum.

Thank you,
Tobi

Jamis
Administrator

Posts: 310

Problem with Reflection in simple JS Raytracing Demo Jan 24, 2022 21:34:54 GMT tobnac likes this

Quote

Post by Jamis on Jan 24, 2022 21:34:54 GMT

Hey tobnac, I believe the issue is how you're computing the normal for the plane. As mentioned in Chapter 9, under "Implementing a Plane", "Every single point on the plane has the same normal: vector(0, 1, 0)." I think you correct that, the reflections (and shading) will render better.

tobnac
New Member

Posts: 2

Problem with Reflection in simple JS Raytracing Demo Jan 25, 2022 19:19:53 GMT

Quote

Post by tobnac on Jan 25, 2022 19:19:53 GMT

Jan 24, 2022 21:34:54 GMT Jamis said:

Hey tobnac , I believe the issue is how you're computing the normal for the plane. As mentioned in Chapter 9, under "Implementing a Plane", "Every single point on the plane has the same normal: vector(0, 1, 0)." I think you correct that, the reflections (and shading) will render better.

Thank you so much!
Actually I don't have the book and were only looking for a quick and dirty js implementation. It bothered me, that everything seemed to work except the reflection of the plane.

The problem was, that i did not normalize the Normal of the plane. Your guess of Vector(0,1,0) really did it for me and I checked for that.
Now it works like a charm: prnt.sc/26j93j1

Thank you so much!