Over a year ago I had a thought that “Shaders must die” (part 1, part 2, part 3).

And what do you know – turns out we’re trying to pull this off in upcoming Unity 3. We call this Surface Shaders cause I’ve a suspicion “shaders must die” as a feature name wouldn’t have flied very far.

(more…)

Realtime shader languages these days have settled down into two camps: HLSL (or Cg, which for all practical reasons is the same) and GLSL (or GLSL ES, which is sufficiently similar). HLSL/Cg is used by Direct3D and the big consoles (Xbox 360, PS3). GLSL/ES is used by OpenGL and pretty much all modern mobile platforms (iPhone, Android, …).

Since shaders are more or less “assets”, having two different languages to deal with is not very nice. What, I’m supposed to write my shader twice just to support both (for example) D3D and iPad? You would think in 2010, almost a decade since high level realtime shader languages have appeared, this problem would be solved… but it isn’t!

(more…)

Just returned from exciting (and exhausting) trip to Game Developers Conference 2010. Random notes:

Unity

It seems that everyone is talking about Unity this year. At GDC 2009 some people have heard about us, some others were “where the f*** this came from?!”, and some had no idea what Unity is. This year it’s hard to find anyone who hasn’t heard about Unity. I was surprised by number of AAA developers who are playing around with Unity internally (for prototyping, mobile & whatnot) and/or are big fans of Unity. I like!

We had a cool booth that was very busy at all times. As a bonus, the Unity chairs could be used as weapons!

Awesome quote: CEO of censored (competing middleware company) said: “yeah, Unity is going up, we are going down”. This is taken completely out of context of course.

We were busy demoing upcoming Unity 3 which I think will be quite awesome. Three days before the conference were spent crunching on the demos for GDC :)

Cool Stuff

Only managed to go to two sessions :(

Stephen Hill‘s “Rendering Tools and Techniques of Splinter Cell: Conviction” had interesting bits & pieces of stuff. Nice work on hierarchical Z occlusion and ambient occlusion fields! (probably first time I see AO fields used in actual game production)

Mike Acton‘s “Three Big Lies: Typical Design Failures in Game Programming” was entertaining. Content wise I pretty much knew what to expect. If you aren’t following Mike – do it now! Talk slides are at Insomniac’s site.

RAD‘s Telemetry profiler looks totally sweet. I think they acquired this one and improved it. Some very good UI ideas in there. On a related note, Scaleform’s new profiler looks… kinda inspired by Unity’s (comparison: Scaleform on the left, Unity on the right).

Fun Stuff

Managed to sneak in some fun (dare I say “social”?) stuff.

Rendering folks dinner (thanks Johan!) was awesome, even if it made me feel kinda small & stupid among those super smart guys & gals. Shadow algorithms on receipts FTW! Middleware Meetup (thanks Dan!) was full of friendly competitors :) #gdcdrink tweetup (thanks Mike!) had lots of war stories, PS3 talk and how to do fluid simulation on 360′s pixel shaders.

Just spent half a day debugging this, so here it is for the future reference of the internets.

In a deferred rendering setup (see Game Angst for a good discussion of deferred shading & lighting), lights are applied using data from screen-space buffers. Position, normal and other things are reconstructed from buffers and lighting is computed “in screen space”.

Because each light is applied to a portion of the screen, the pixels it computes can belong to different objects. If in any place of lighting computation you use textures with mipmaps, be careful. Most common use for mipmapped light textures is light “cookies” (aka Gobo).

Let’s say we have a very simple scene with a spot light: (more…)

…I took a plane to Copenhagen. Oh, this sounds familiar…

Well ok, it all started a bit before: (more…)