Desktop GUI: selecting individual spins

[GPMueller]

The use would be:

• insert defects
• pin individual spins
• select starting points for stream-tubes

There are three requirements:

• get the collision point of the mouse with the nearest instance
• get the lattice site (i.e. the index) from the collision point
• highlight the selected spin somehow

The following would have to be implemented

1. read the z-buffer, transform to normalized and together with x and y transform it to world coordinates https://www.khronos.org/registry/OpenGL-Refpages/gl2.1/xhtml/gluUnProject.xml
2. find nearest unit cell center from collision point, then inside the unit cell find the nearest spin
3. maybe cell-shading+outlining of a white spin? This could be difficult, as a single spin has to somehow be excluded from the regular rendering, but drawn by a different renderer