# Posts by ghost.yu

• ## Can canvas be used as distorted hotspot

Hi, all

I can use canvas as a render object for videoDOM, but when drawing transparent images or cropping images, the black background of the hotspot itself is always there.

Can you provide a method to remove the black background.

• ## How to make the hotspot not face the camera during dragging (moving).

Thanks you for your reminder, but I only have an ath atv to determine the end position, no tx ty tz changes.
Later, I calculate the Euler angle of rotation between the start and end points by reversing the ath atv, and then apply it to the hotspot by mixing its own rotation.
The effect is very good, it meets my needs.

• ## How to make the hotspot not face the camera during dragging (moving).

hi,
To move the point from (20, 20) to (50, 20) in the 3d distorted state, just apply ry=30, The hotspot appears to be translated a distance.
However, if you go from point (20, 20) to point (50, 50), there will be a deviation in changing rx and ry.
How to calculate an Euler angle through the coordinate motion trajectory to react on the hotspot

• ## How to make the hotspot not face the camera during dragging (moving).

The hotspot moves from the point (20, 20) to the point (50, 50), and it always faces the center of the sphere during the movement.

Is there a way to make the hotspot from the beginning to the end of the movement, not towards the center of the sphere,

which seems to be multiplied by a rotation matrix

• ## How to make the hotspot not face the camera during dragging (moving).

Hi, all

How to make the hotspot not face the camera during dragging (moving).

Thanks.

• ## Use three.js (3d objects) inside krpano (with VR support)

How to set the correct rx ry rz with quaternion to keep it consistent with the local rotation of three.js