Some more optimizations

When you care about performance of a system you need to look everywhere. You start optimizing your code for the critical points, in the case of a render engine that might be ray traversal, shading code... acceleration structure build.

Lately I'm quite happy with Glimpse rendering speed, but somthing that always bothered me is how long it takes to get data from the host application, in this case Maya, to the render engine.

In the past I used to wait 10 minutes for a preview rendering. In this case 15 seconds of frame translation is not a big deal. But now I can get a low quality noisy frame rendered in a fraction of a second. In this scenario a 10 sec frame translation is boldly inappropriate!

I was doing some tests the other day. Frame rendering was about 70" for a very clean quality at 2k resolution; about a second for an half-res low auality preview, but 26" of data translation.

It turns out that many Maya API calls are rather slow. Some to avoid like pleague is MItMesh*.

Some others particularly slow subsystems are light linking and materials assignments. If you are ever trying to write your own translator from Maya, do yourself a favor and extract such data from plugs and connections rather than relaying on higher level API to do the work for you.

After some changes translator is between 4-7 times faster now.

Sorry, no pictures this time :)