Rotation with a mouse drag

[paireks]

Hey guys!

I really apprieciate the example files for OpenGL and Imgui, they explain a lot. One thing I try to figure out, is making it possible to rotate 3d models using mouse dragging. In example files there is some sort of a fly mode, which is really cool and helpful, but at the same time for CAD related things rotating it with mouse dragging is much more popular. What I mean by this is something like e.g. this: https://stemkoski.github.io/Three.js/Labeled-Geometry.html

I understand library itself is pretty low-level, but maybe any of you have any examples or code samples where you rotate it not by flying with arrows and mouse, but with just dragging the mouse? :)

[desiwko]

This functionality is a pretty simple algorithm non-specific to any particular code. Simplified algorithm:

1. Capture the initial mouse down coordinate
2. Track the mouse move coordinate while mouse down
3. Calculate the vector between the two points, normalize if/as desired
4. Create a rotation matrix from calculated vector
5. Apply rotation matrix to object
6. On mouse up, break out of the tracking loop

[paireks]

Then I think calculating step 4. (vector to rotation matrix) is what I'm looking for :) I will try to find it on web, thank you

[paireks]

Just a small note that there is a repo that does that: https://github.com/batu92k/Mouse-Orbit