• Announcements

    • khawk

      Download the Game Design and Indie Game Marketing Freebook   07/19/17

      GameDev.net and CRC Press have teamed up to bring a free ebook of content curated from top titles published by CRC Press. The freebook, Practices of Game Design & Indie Game Marketing, includes chapters from The Art of Game Design: A Book of Lenses, A Practical Guide to Indie Game Marketing, and An Architectural Approach to Level Design. The GameDev.net FreeBook is relevant to game designers, developers, and those interested in learning more about the challenges in game development. We know game development can be a tough discipline and business, so we picked several chapters from CRC Press titles that we thought would be of interest to you, the GameDev.net audience, in your journey to design, develop, and market your next game. The free ebook is available through CRC Press by clicking here. The Curated Books The Art of Game Design: A Book of Lenses, Second Edition, by Jesse Schell Presents 100+ sets of questions, or different lenses, for viewing a game’s design, encompassing diverse fields such as psychology, architecture, music, film, software engineering, theme park design, mathematics, anthropology, and more. Written by one of the world's top game designers, this book describes the deepest and most fundamental principles of game design, demonstrating how tactics used in board, card, and athletic games also work in video games. It provides practical instruction on creating world-class games that will be played again and again. View it here. A Practical Guide to Indie Game Marketing, by Joel Dreskin Marketing is an essential but too frequently overlooked or minimized component of the release plan for indie games. A Practical Guide to Indie Game Marketing provides you with the tools needed to build visibility and sell your indie games. With special focus on those developers with small budgets and limited staff and resources, this book is packed with tangible recommendations and techniques that you can put to use immediately. As a seasoned professional of the indie game arena, author Joel Dreskin gives you insight into practical, real-world experiences of marketing numerous successful games and also provides stories of the failures. View it here. An Architectural Approach to Level Design This is one of the first books to integrate architectural and spatial design theory with the field of level design. The book presents architectural techniques and theories for level designers to use in their own work. It connects architecture and level design in different ways that address the practical elements of how designers construct space and the experiential elements of how and why humans interact with this space. Throughout the text, readers learn skills for spatial layout, evoking emotion through gamespaces, and creating better levels through architectural theory. View it here. Learn more and download the ebook by clicking here. Did you know? GameDev.net and CRC Press also recently teamed up to bring GDNet+ Members up to a 20% discount on all CRC Press books. Learn more about this and other benefits here.
Sign in to follow this  
Followers 0
neroziros

[HLSL] Copy content of Consume Buffer to Structured Buffer

8 posts in this topic

Hi all!

 

I was wondering if it is possible to copy the content from a consume buffer to a structured buffer.

 

A little more context: I'm working with a dynamic particle system and, to accomplish inter-particle interaction, I need to compare each particle of the system against each other particle of the same system. The problem is that since I cannot index a consume buffer (to just peek at the values instead of consuming them), I don't know how to do this without copying its content to a structured buffer each frame.

 

Cheers and thanks in advance for your time!

 

PS: The reason why I don't use a structured buffer to store all particles in the first place is because the system is of variable size, creating and destroying particles each frame, which I made easily using append and consume buffers.

Edited by neroziros
0

Share this post


Link to post
Share on other sites

Thanks for the advice, it worked! Though now I have a problem: I can't bind the same buffer as a consume buffer and StructuredBuffer at the same time. If I try this, when I access the values of its consumebuffer version they are ok but on its structuredbuffer version they are null. I suppose this is for memory safety reasons.

 

If I'm correct I could solve this by copying the content of the consume buffer to an auxiliary structured buffer with CopyStructureCount. Will try and report results.

0

Share this post


Link to post
Share on other sites


If I'm correct I could solve this by copying the content of the consume buffer to an auxiliary structured buffer with CopyStructureCount. Will try and report results

That's right - and if you have the debug device activated, then you should also get warnings / errors about binding the same resource for input/output (UAV) and input (SRV) at the same time.

2

Share this post


Link to post
Share on other sites

Hmm it works but it is badly hurting the performance of the program (It went from 60fps to 30fps). I'm copying the content of the consume buffer with the CopyResource function. Is this problem happening because I am doing this copy each frame? Does someone knows a workaround?

 

Thanks again!

Edited by neroziros
0

Share this post


Link to post
Share on other sites
Don't make assumptions, profile. Could be that it's not the copying being the problem (see below).

If you can, use a GPU profiler (e.g. NVidia's NSight). MJP also has a blog post about using timer queries, though I never could use them for compute shaders with my NVidia, unfortunately.
 
That being said, I'm a bit concerned about this:

I need to compare each particle of the system against each other particle of the same system

 
This sounds like an O(N2) approach, which is already bad in itself. Do you use a spatial acceleration structure at all ? Here's an example using a uniform grid (though with a classic pipeline, not compute shaders). And here's some collision detection with CUDA. Or google for some GPGPU implementation/articles of SPH (smoothed particle hydrodynamics).
2

Share this post


Link to post
Share on other sites

I ran the profiler and indeed the problem is CopyResource. However now I know why. According to the docs "Doing this frequently at runtime will severely degrade performance... The application needs to wait long enough for the command buffer to be emptied and thus have all of those commands finish executing before it tries to map the corresponding staging resource. ".

 

I managed to minimize this problem by doing the copy each 5 frames instead of every frame. It is not perfect but I think I should be able to get good approximate results this way.

 

Thanks for those articles I will check those out! Indeed as I am doing it right now it is a O(N2)  approach and it is killing the performance when I am around 100k particles. 

Edited by neroziros
0

Share this post


Link to post
Share on other sites

Just a quick suggestion regarding your performance problem with CopyResource.  The performance warning in the docs only relates to DstResources created with their usage set to D3D11_USAGE_STAGING.

 

Assuming you only need CPU-write acess to your consume buffer, then so long as you create your consume buffer (the pSrcResource) with D3D11_USAGE_DYNAMIC and your second structured buffer (the pDstResource) with D3D11_USAGE_DEFAULT, the CopyResource shouldn't cause a pipeline stall.  Apologies if I'm mistaken, but it might be worth checking those usage flags on the resource creation.

0

Share this post


Link to post
Share on other sites

Thanks for the advise but it didn't work. It seems I can't set the consume buffer flag with D3D11_USAGE_DYNAMIC because I need to consume particles from that buffer, and D3D11_USAGE_DYNAMIC don't allow write operations from the GPU side (only CPU)

 

Cheers!

0

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!


Register a new account

Sign in

Already have an account? Sign in here.


Sign In Now
Sign in to follow this  
Followers 0