Can we intersect fragment/raymarched "object" with regular mesh?

Questions
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1

I’d like to take something like the blobs/metaballs in this demo:

and intersect them with regular meshes. Never done that before.

I’m guessing that if I use gl_FragDepth, I can specify the depth of the fragment drawing, and this can make the pixels result in being in front of or behind of regular meshes.

If so, is there a demo of this?

EDIT: similar question: How I can combine a shader based rendering and three.js scene graph

2

You can do this. I’ve done it before… and iirc yes it involves using gl_FragDepth if you want correct depth values. I don’t have any samples I can point you to though. I think when I did it, I used a cube, and did the raymarching in the cubes shader.

Here’s a project that uses SDFs for modelling and is quite nice:

Another approach is to extract the SDF into a buffergeometry via marchingcubes. I haven’t messed with this much but it looks promising?

https://threejs.org/examples/?q=SDF#webgl_geometry_sdf