• 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
pcmaster

DX11
Concurrent fragments writes

3 posts in this topic

I have a rather low-level GPU question.

Is it possible, that two or more fragments (perhaps from different primitives) with the SAME xy target (screen) coordinates are ever being executed concurrently by multiple GPU threads?

It sounds weird, let me rephrase it just to be sure [img]http://public.gamedev.net//public/style_emoticons/default/smile.png[/img]

Say I submit 2 triangles that will project to the very same target xy pixels (they might or might not have different z (depth)).
1. For each of the 6 vertices a vertex shader will be invoked and all these 6 vertex shaders run at once (there's plenty of groups and units on the GPU, right?)
2. There is no geometry shader (irrelevant). Both triangles will project to the same pixels of the target. Rasteriser rasterises and pixel shaders get invoked...
3. Is there a possibility that two pixel shaders (one for a fragment on triangle 0 and one for another fragment on triangle 1), which want to shade (and possibly write or scatter) at the very same target (screen) location, get executed really concurrently (obviously on different thread groups)???

I suppose yes. I am obviously looking for the worst-case scenario. Am I right? Early-Z, presence of discards and explicit depth-writes and similar peculiarities probably have a say in this.

Next question would be (DX11/GL4) if it is necessary to have ANY output target bound to the output merger, or is it enough to bind [b]0 RTVs[/b] and 1 UAV (OMSetRenderTargetsAndUnorderedAccessViews()). I'm not talking compute shaders.
0

Share this post


Link to post
Share on other sites
Part 1: Theoretically, yes, they can run concurrently. The D3D/GL specs are intentionally not too specific about how this works under the hood, just that the end result needs to be deterministic. There *may* be specific hardware implementations that kill or rearrange operations if this happens in practice, but there are no blanket 'this is how it must work' restrictions I am aware of. When in doubt, use atomics.

Part 2: Good question, I think you may be okay. It's entirely possible to do depth-only rendering by not binding any RTVs (just a DSV) and I would think the same would apply here.
1

Share this post


Link to post
Share on other sites
This is implementation specific (and I do know of cases where this is and is not true), but yes, on most high end graphics hardware this will happen. Post-shader, there is the requirement that fragments must appear to be rendered as though they were in triangle order.
1

Share this post


Link to post
Share on other sites
Thank you very much guys. I will then have to assume (despite your last sentence, Crowley99) it will happen and I will use atomics. I'll try to update it here with performance and results, all if I get to try the 0 RTV + 0 DSV + n UAV scenario.
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

  • Similar Content

    • By YixunLiu
      Hi,
      I have a surface mesh and I want to use a cone to cut a hole on the surface mesh.
      Anybody know a fast method to calculate the intersected boundary of these two geometries?
       
      Thanks.
       
      YL
       
    • By hiya83
      Hi, I tried searching for this but either I failed or couldn't find anything. I know there's D11/D12 interop and there are extensions for GL/D11 (though not very efficient). I was wondering if there's any Vulkan/D11 or Vulkan/D12 interop?
      Thanks!
    • By lonewolff
      Hi Guys,
      I am just wondering if it is possible to acquire the address of the backbuffer if an API (based on DX11) only exposes the 'device' and 'context' pointers?
      Any advice would be greatly appreciated
    • By MarcusAseth
      bool InitDirect3D::Init() { if (!D3DApp::Init()) { return false; } //Additional Initialization //Disable Alt+Enter Fullscreen Toggle shortkey IDXGIFactory* factory; CreateDXGIFactory(__uuidof(IDXGIFactory), reinterpret_cast<void**>(&factory)); factory->MakeWindowAssociation(mhWindow, DXGI_MWA_NO_WINDOW_CHANGES); factory->Release(); return true; }  
      As stated on the title and displayed on the code above, regardless of it Alt+Enter still takes effect...
      I recall something from the book during the swapChain creation, where in order to create it one has to use the same factory used to create the ID3D11Device, therefore I tested and indeed using that same factory indeed it work.
      How is that one particular factory related to my window and how come the MakeWindowAssociation won't take effect with a newly created factory?
      Also what's even the point of being able to create this Factories if they won't work,?(except from that one associated with the ID3D11Device) 
    • By ProfL
      Can anyone recommend a wrapper for Direct3D 11 that is similarly simple to use as SFML? I don't need all the image formats etc. BUT I want a simple way to open a window, allocate a texture, buffer, shader.
  • Popular Now