Hotspots disappearing when zooming in (flat pano)

Hey there,

it's me with a strange problem again

I created hotspots as horizontal and vertical helper lines that you can move around.

See: Example

Those lines should only be 1 pixel wide, always be the whole size of the screen and be always on the same position when zooming.
So far that all works as intended.

However: When you zooming in, the lines disappear - depending on the view position.
So when you zoom in at the image center (where the lines cross) you can zoom in all the way.
When you go to the left/right/top/bottom however the line are gone at some level.
So more you move out of the center so further you have zoom out to see the lines.

Can someone help me with this problem?
I first thougth about playing with the zoom and distorted attributes but using those I can't get 1 pixel lines working as you need some scale than.

Thanks for any advice!

Update: Bug is also present in krpano 1.21 (build 2023-03-15)

Quote from klaus.krpano

Hi,

that kind of problem should appear in all versions (1.19, 1.20, 1.21).

It's about the frustum/visibility checking of hotspots (if they are out of the screen-range to avoid rendering them).

And here currently only a simplified check is used for performance reason and that unfortunately fails for extremely large hotspots...
But improving this is already on my list.

Best regards,
Klaus

Thanks for the clarification. That explains why it totally disappears at a specific pixel when moving.

Do you have a ETA in mind for when the fix could happen?

If it would take longer due to low priority (what I could totally understand) I would try to work around by "pulling" the hotspot close to the view.fov with onviewchange - guess that should work.

Thanks again!

Hi Klaus!

Turns out that making the hotspots smaller an pulling them to the center to always cover the full screen isn't a good solution. As this has to happen on every onviewchange call and must be a loop to "pull" all hotspots it get's really slow if there are more than a few hotspots.

So a solution for this big-hotspot behaviour in one of the coming releases would be so much appreciated!

Quote from klaus.krpano

Hi,

this will be fixed in the next release.
I have implemented now a pixel-exact visibility check for the 'flat/2d'-hotspots.

Best regards,
Klaus

This is so good news - thank you very much for it!

Hi Klaus,

thanks for the update!

It actually works better now. However the lines still disappear sooner than I would have liked for my usecase.

For example a verical line vanishes at:
hlookat: -0.481639
vlookat: - 0.260689
hfov: 0.018952
vfov: 0.014214

Probably the values already get to small here?
At least I can see it disappear pixelperfect now

Greetings
Stefan

Aaaand I was wrong!

Actually it does work so good, that the lines got to short while zooming in - that was never a problem so far obviously, as they just vanished before

So I made the lines much longer and now everything just works as good as I could imagine.

THANK YOU Klaus!