These days, I’m trying to import 3D models exported as Wavefront OBJ files in my Vulkan renderer. In order to achieve that effortlessly (kinda), I’m using the very good Assimp (pun not intended) library.
It kinda works well if you stick to a « traditional Blinn-Phong » lighting pipeline (also known as « prehistoric lighting » 😉 ), with ambient/diffuse/specular components and so on. Everything is there. Things become trickier if you try to bring PBR into the mix, with roughness, metallic and ambient occlusion maps for example.
What parameters should you use in Assimp to read those values ? What texture type should be used in order to import those maps ? Turns out it’s not as easy as one would think, because support on both the Wavefront OBJ specification and Assimp is just not there.
I’d like to talk here about two not-so-new features of C++ (auto types and lambda functions) that managed to bite me recently, even though I thought I knew them well enough (I still do!).
According to me, it doesn’t show that one should ditch them into oblivion and neveruse them (but some people make their life easier by doing so), but clearly that they should be handled with care, as they more or less act as syntactic sugar on C++ type system, which can be, unfortunately, both overly rigid (which is why we use them in the first place) and overly flexible (which is usually why bugs get in our way).
This isn’t a « true » reblog, but I just wanted to say that I had the same problem than the author of the blog post I’m about to link, and that his solution just did the trick for me too, so I thought I would give him full credit for the solution given it just worked completely unaltered in my situation too.