Distance based fog?

[greggman]

Should fog be distance from camera instead of distance from camera's zplane?

Currently fog is just the z distance from the zplane of the camera. That means if you just turn the camera in place objects that are not really getting closer to the camera come out of the fog. That doesn't seem correct (although maybe it's intentional?)

Here's 6 cubes in a circle around the camera. The camera is spinning in place. you can see the cubes come out of the fog even though they are not actually closer to the camera

http://jsfiddle.net/greggman/Lx3mhvbe/

Changing the fog from this

fogDepth = -mvPosition.z;

to this

fogDepth = length(mvPosition);

Seem like it might work?

Example: https://fog-fix.glitch.me/

Not sure it's correct but the objects are no long coming out of the fog

Three.js version

• Dev
• r94

[Mugen87]

I think this is a good suggestion.

[WestLangley]

Ditto.

@greggman Do you want to file a PR?

[mrdoob]

Agreed. I never liked this fog technique.

[WestLangley]

Actually, this approach only works correctly if the distance is calculated in the fragment shader, not in the vertex shader. So #14602 will have to be reverted for now.

[barnabasbartha]

Is there any progress about this issue?

[amitukind]

Is there any progress on this? I have implemented it and I am going to create a PR.

[Mugen87]

There is already a PR for this, see #17592.

And this is the leading issue: #17420

[amitukind]

@Mugen87 I need to change in realtime all object's opacity based on their distance from the camera. The fog technique doesn't work there. Changing manually in animate is consuming a lot of CPU.