Check if inside Object

[markusmoenig]

Hi, I am writing an SDF modeler and for the ray marching to be correct I need to know if the path tracer state is currently inside or outside an object.

Would that be somehow evident from the State struct ?

Thanks

[knightcrawler25]

You can probably get that information from the surface normal. If state.normal and state.ffnormal are on the same side i.e. dot(state.normal, state.ffnormal) > 0 then the ray has hit the surface from the outside, otherwise the ray has hit the inner surface.

[markusmoenig]

Thanks, that makes sense. I just need to make sure to inverse the ray marching direction when inside as otherwise I would trace back.