3d2png's tests fail for me with node 9.5 on macos 10.3. Some patches:
- Compat fix for node >= 7: https://gerrit.wikimedia.org/r/#/c/413182/
- Close out the written PNG before reading it: https://gerrit.wikimedia.org/r/#/c/413183/
- Update the rendering to current: https://gerrit.wikimedia.org/r/#/c/413184/
I'm not certain that my new rendering is correct in terms of texture/background, but I notice that the direction of view has changed recently and the sample rendering didn't get updated, causing a wildly mismatched MSSIM value.