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rdragon1

Member Since 07 Feb 2001
Offline Last Active Jun 27 2014 11:16 PM
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Posts I've Made

In Topic: Metal API .... whait what

05 June 2014 - 07:53 AM

They mention a 4xMRT limit, so 4 x 4x32bit follows on from that anyway, seeing as 4x32bit is the fattest texture format biggrin.png

But yes, a "feature level" API would be nice, so you can ask the device what kind of limits it actually has.

 

BTW, I wouldn't dare use 4 x 4x32bit on the nextgen consoles! That's way too much bandwidth -- At 1080p, that's over 120MiB of framebuffer!

(or if you assume a perfectly optimal only 1 write followed by 1 read per pixel, then at 60Hz that's 14.8GiB/s of bandwidth)

3 x 4x8bit is a pretty standard setup for deferred rendering, and even that's uncomfortable from a bandwidth point of view...

 

Keep in mind that on Xbone, you want to keep your frame-buffers under ~30MiB! 3 x 4x8bit plus a depth buffer just barely fits in 32MiB of ESRAM.

 

3 x 4x8bit isn't uncomfortable on next-gen consoles. I guess Xbone has more restrictions here, but Infamous Second Son used 6 1080p gbuffer targets + depth + stencil - 3 of the gbuffer targets are 4x8bit, the other 3 are 4x16bit. See slide 41 here: http://suckerpunch.playstation.com/images/stories/GDC14_infamous_second_son_engine_postmortem.pdf


In Topic: The 128-bit Operating System

21 May 2014 - 08:54 AM


DCAS with 128 bit pointers would be fun...

 

By DCAS do you mean an atomic compare-and-swap? Why would you need/want a larger pointer / address space? Or do you simply want to do a CAS on 16 bytes? If so, x86 already has the cmpxchg16b instruction.

 

128 bit pointers will waste a lot of memory. 64 bit pointers already do. Why do you currently think you need to address more than 2^64 bytes?


In Topic: Why discard pixel take a noticeable performance hit?

16 April 2014 - 11:39 AM

For a discarded pixel you've already paid the cost of its fragment shader even though it doesn't writa anything. Further, you'll have to at least run the fragment shader for the visible geometry behind it, so that's an added cost. This really adds up if there's lots of overlapping discarded pixels - lots of fragment shader computation performed, with the results thrown away.


In Topic: Generic Datatypes --Are Templates the Way to Go?

17 August 2013 - 02:38 PM

Yes, these are "intrusive lists" and I would use caution when deriving from a type to add 'next' and 'prev' pointers to your object. What do you do when you want the object to be in more than one list? Also, how do you keep code from looking confusing - going this route, if you add an object to a list, you have to remember you're implicitly removing it from any list it was in previously.


In Topic: Xbox One and Indie Dev

24 May 2013 - 02:36 PM

XBLIG is for the little guys, hobby developers, and small companies.

 

But XBLIG required you to build on top of XNA, right? And XNA is dead, and I haven't heard anything about XNA games running on XBone, so.....? (To me that sounds like XBLIG is simply not coming to xbone)


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