The Shadow Knows

There has been a virtual (pun intended) explosion of SL-based viewers lately; it seems everybody has nifty -- and not-so-nifty -- ideas on how to improve Linden Labs' open-source code. The Hippo Viewer, for example, has become the "standard" viewer for the OpenSim world.

Gwyneth Llewelyn has been playing with shadows. Dynamic shadows can be enabled in SL 1.23 -- if you have a high-end graphics card. As anyone who has played with ray tracing knows *raises hand*, shadow casting usually involves a lot of CPU processing time.

But Gwyn has found another SL viewer, by Kirstenlee Cinquetti, that sounds exciting:

[ . . . ] there is simply none of the SL viewers I’ve tried that have the same raw performance than her viewer. And thanks to Hyang Zhao’s work, I can test some of the latest versions of Kirstens Viewer on my poor underpowered Macs too.

It’s always a pleasure to install it, specially on the poor MacBook (not Pro), which gets some 5 or 6 FPS out of the latest batches coming out of LL, as well as on all derivative viewers. Kirstens Viewer just runs flawlessly over 15 FPS out of it — sometimes more, on empty sims. Of course I can’t turn most things on — even Basic Shaders will crash the MacBook, US$10 Intel cards are simply not up to it — but I can get pretty reasonable results. Enough for work; enough for demonstrations.

On my early-2007 iMac, however, things are quite different. You should take into account that Linden Lab works very hard to get a reasonable 15 FPS on almost all computers from the past 3 years — and except for the ones with too low cards, that’s what you should expect to get with “reasonable” settings. I definitely get that on the iMac — with Snowglobe, even with the Atmospheric Shaders on. This is actually quite reasonable.

Kirstens Viewer has allegedly a partial redesign of the whole rendering engine and the texture pipeline. Although I don’t see such a huge difference about texture downloads — LL has done enough improvements on their side as well — Kirstenlee has also incorporated the new lighting engine. Yes, the very same that allows unlimited lights in a scene, and uses new hardware-based tricks on the graphics card to give a boost in performance. The results? Even on old, outdated, obsolete graphics cards you should see an improvement — both in much nicer rendering (the new lighting system is astonishingly good), and in additional raw performance. For me, it means a boost of at least 50%, and when you have so few FPS, 50% does really make a difference (on a top-of-the-line graphics card you might see little difference — except on much nicer rendering).

I’m actually eager to see if Kirstenlee is willing to put her code in Snowglobe Now that would be something!

But I’ve left the most astonishing feat of the latest version of the Kirstens Viewer (S-17-2 build 198 as I write) for the end: shadows work… even on computers/graphics cards where they shouldn’t!

I downloaded the Kirsten Viewer and tried it out briefly this evening. When I followed the directions in Gwyn's blog to enable dynamic shadows:

1. Make sure you have a DirectX 10 compatible card (eg. nVidia 8 series or newer)
2. Make sure Atmospheric Shaders is on
3. Open the Advanced menu (if you don’t have it yet, press Ctrl+Alt+D)
4. Go to Debug Settings…
5. Type renderuseFBO
6. Change value to TRUE
7. Type renderdeferred
8. Change value to TRUE
9. Welcome to the world of dynamic shadows.

shadows suddenly appeared.


The CTRL-SHIFT-1 diagnostic window shows a pretty steady framerate around 15 FPS. Of course, this is in Arianti, which is a quiet sim with very little lag most of the time. I went to the Hollywood sim and got between 6 and 8 FPS. Turning off RenderDeferred in the Debug Settings to disable shadows let the frame rate go back up to 10-15 FPS.


Shadows will add an extra dimension of reality to our virtual existance. Let's hope that Kirsten's improvements make it into other viewers, especially future "official" SL clients.