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Old 03-05-11, 04:53 AM   #191
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Join Date: Jun 2010
Posts: 165
Default Re: Battlefield 3 News/Info

Originally Posted by Logical View Post
The particle lighting is especially impressive, Crytek could learn a few tricks from this engine
Actually that is already in in CE3 and Crysis 2 and with even more rendering effects applied to particles. Watch some night gameplay videos from leak.

Even at this early stage the game is absolutly jaw dropping.......Say hello to GOTY 2011 and probably the best PC game of the last decade, imo of course.
Agreed, certainly atleast running head to head with Cryteks offer so far.

Btw heres a highres frambuffer captures of city showing No AA, SRAA, 16xMSAA.

More tech info.

Waiting right now for Christina Coffin's talk on SPU based deferred shading in Battlefield 3. I hear they use DX11 compute shader heavily on the PC side, so it'll be interesting to see how they leverage the SPUs.

* Previous DICE games were forward rendered, just a few lights. Mirror's Edge, which they SHOULD be making a sequel to, used pre-rendered radiosity lighting. Goal of Battlefield 3 was to really expand the lighting and materials, and DICE picked deferred.
* Their PS3 implementation uses 5-6 SPUs in parallel with the GPU and CPU.
* GPU does the initial G-buffer fill, and then passes it off for shading by the SPU. Still waiting to see what that means. Are they using SPUs as fragment shaders?
* The framebuffer is sliced into 64x64 tiles, use a simple shared incrementing counter for sync.
* SPUs compute 16 pixels at a time, in SoA format at full float precision
* The GPU is still busy on other shading while the SPUs eat through the deferred shading
* About 8 millis real time on 5 SPUs for deferred shading while GPU does other stuff, equals 40ms total max compute time contributed by the SPUs.
* Light culling is done in two stage tile hierarchy, after whole-camera and coarse Z in light volumes
* A branch is used to skip all 16 pixels if the attenuation makes them unlit. This is a net win despite the branching cost.
* The SPUs are very even pipe heavy due to all of the FPU action, so complex functions can be replaced with a look-up table using strictly odd-pipe instructions, can decrease 21 cycle functions to 4 in case of complex functions.
* There is still a pure GPU based implementation of the shading pipeline that maintain visual parity, in order to facilitate debugging and validation.
* SPU job code can be reloaded into the live game, enabling bug fixes with quick iteration.
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