Need to show a light emerging from source

i want to show light emerging from lighthouse but spotlight just showing to floor.

provided the current working of a project above.

want spotlight to behave like below

I used this for such purpose: GitHub - jeromeetienne/threex.volumetricspotlight: three.js extension to provide a volumetric spot light

if you want to consider react this is a one-liner: Volumetric spotlight - CodeSandbox but otherwise you find the vanilla threejs shadermaterial here: drei/SpotLightMaterial.tsx at e3aafb0ffaa4c8a99927c0c0edd51950f87a4aab · pmndrs/drei · GitHub the technique is called “soft-particle” which avoid the visual glitches and makes it look pretty convincing.

can’t it be done with native Spotlight without any external library?