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megafenix on 26 October 2014
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fatslob-:O said:
curl-6 said:

I am aware it is a technique. One that makes it more efficient to do some things. It's not so much that it's a feat, more that it's something Wii U seems better equipped for than last gen consoles.

"Better equipped" is questionable since a G-buffer which consists of multiple render targets doesn't exactly have a very small footprint to be able to fit all of the render targets on the eDRAM and the WII U doesn't exactly have a very high memory bandwidth either to help the situation ... 


for wii u edram having enough bandwidth for triple frame buffers of 720p plus a gbuffer and plus intermediate buffers and such then that means has plenty of bandwidth. seems that for the 360 they needed 12MB of edram for the g-buffer which obviously were not present and had to come up with workarounds to reduce memory bandwidth requirements, in wii us case knowing that needs about 7.2MB of edram for the 720p with double buffering and that 360 required 10MB FOR THE 720P WITH DOUBLE Buffering that would mean about 8.64MB for the g-buffer

 

here

http://www2.disney.co.uk/cms_res/blackrockstudio/pdf/BlackRockStudioTechnology_Deferred_Shading.pdf

 

and here microsoft themselves confirms that 10mb of edram was just enough for the 720p with double buffering

http://msdn.microsoft.com/en-us/library/bb464139.aspx

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Predicated Tiling

 
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Describes predicated tiling in Xbox 360 development.

The Xbox 360 has 10 MB (10×1024×1024) of fast embedded dynamic RAM (EDRAM) that is dedicated for use as the back buffer, depth stencil buffer, and other render targets. Depending on the size and format of the render targets and the antialiasing level, it may not be possible to fit all targets in EDRAM at once. For example, 10 MB of EDRAM is enough to hold two 1280×720 32-bit surfaces with no multisample antialiasing (MSAA) or two 640×480 4× MSAA 32-bit surfaces. However, a 1280×720 2× MSAA 32-bits-per-pixel render target is 7,372,800 bytes. Combined with a 32-bit Z/stencil buffer of the same dimensions, it becomes apparent that 10 MB might not be sufficient.

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this means taht while 360 had barely neugh bandwith in those 10MB of edram for the doube buffering with 720p, wii u has almost what is required for triple buffering of 720p in 10MB, the difference is just a margin of 0.8MB. adding up a gbuffer would be just 8.64MB, which combined with triple framebuffer would be 19.44MB od edram, we still have plenty enough for the intermediate buffers and maybe other things since wii u has 32MB of main edram plus 2MB of faster edram and 1MB of sram, of course that maybe the extra edram and sram p[ools could be meant to the cpu