Strange behavior of dolly to cursor zoom out

[fukuken1968]

Describe the bug

see the attached screenshot

To Reproduce

Steps to reproduce the behavior:

1. check 'dolly to cursor'
2. rotate the mouse wheel (repeat increasing and decreasing)
3. drawing disappears at a certain timing

Code

Live example

https://yomotsu.github.io/camera-controls/examples/orthographic.html

Expected behavior

Do not disappear even if zoom out in dolly to cursor mode.

Screenshots or Video

Platform:

• Device: [Desktop]
• OS: [Windows]
• Browser: [Chrome]

[yomotsu]

Thanks for your report. Reproduced. It seems only happens if the camera is facing every 90deg (front, side, and so on)

[blksky]

I have the same problem.

[msemtd]

I assume that the camera position is moving and the camera far frustum is clipping the scene.

[yomotsu]

I guess the cause of the problem is here: https://github.com/yomotsu/camera-controls/blob/c35908d208fe0d695ec7d9aa5de8ee247dc3b611/src/CameraControls.ts#L2240-L2241

If the camera is facing the front (or every 90degs), then the divisor above will be 0, then causes unexpected behavior. We should re-consider zoom-to-cursor (not dolly) in orthographic calculation...

[blksky]

Is there a solution?

[yomotsu]

Unfortunately, this is quite complex. Actually, zoom-to-cursor in orthographic behaves as dolly, as a result, the camera moves out of the clipping plane. Users should not use zoom-to-cursor in orthographic😢 OrthographicCamera must not dolly and should use zoom instead correctly.

[yomotsu]

I think this problem has finally been fixed at https://github.com/yomotsu/camera-controls/pull/322