Bluestone in action

Porting Bluestone over to SlimDX has been a lot easier than I anticipated so I thought I'd post a video of it up and running. There are still a few systems yet to be ported but the core is fully functional.

The video shows a couple of scenes being rendered although I've edited out the sections of video where it's rendering. The render times are quick but still, I figure you have better things to do :) I've noted the actual render times on screen wherever an edit has taken place.

A few words about the technique I use in the videos. I basically start out with a direct light pass and make sure that everything is as it should be. Once I'm happy with that I do a few quick low quality GI bounces to illuminate the shadowed areas. Usually about 256 - 512 rays, depending on the scene. Once that's looking good and I can see that light is getting into all the corners I do a final pass at about 2000 - 4000 rays to get the final result.

I'm really keen to hear peoples thoughts on Bluestone so send me an email or leave a comment. I especially want to hear from you if you're working on something and think Bluestone would be useful as I'm looking for testers.

Bluestone GPU lightmapper update

2.1 million sample points rendered in 6 seconds (Bluestone screenshot)

The GPU lightmap renderer I've been developing (Bluestone) is written in XNA. It's always been a concern that the remit of XNA most definitely isn't GPU lightmap renderers but until recently that hasn't been an issue.  Unfortunately, the changes made to the framework in XNA 4.0 (link) mean that using XNA for this type of application is probably no longer practical. The biggest issue for me is the loss of control over render targets and depth buffers. In XNA 4.0 render targets are automatically assigned depth buffers. Meaning it's no longer possible to reuse a single depth buffer among multiple render targets, which is what Bluestone requires.

In order to move the project forward I needed to look elsewhere. There were a few different options but I've gone with SlimDX, for several reasons. I can stick with C# for one but it also has the advantage of opening up a lot of very nice DirectX 10 features not available in XNA. So far the porting has gone well and both the direct and indirect lighting systems are in place.

In related news, an unexpected win was a decrease in global illumination render times. I made some alterations to the GI shader which have worked wonders. I need to test it more widely but the improvement seems to be about 30% in most cases.