Vulkan -New Replacement For OpenGL

https://www.khronos.org/vulkan

Trying to get my head round what this means so i thought I would toss it on the forums here for all you graphics/shader programmer heads to chime in and delineate what this means for game dev.I notice Unity had it's logo on the page as well..so how in particular will this affect how we use Unity, affecting frame rates, new grfx capabilities etc.

 

In short it's not bloatware anymore, all-in-one API with a bunch of tweaks written from the ground up. So in essence should be a lot faster, contain all the latest graphics options and combines mobile and desktop into a singular package.

I think Unity might of known about this for a while, so it was a good move not to upgrade to GL4. Then again, they could of just said that.

 

I guess @Aras will have the best answer when it comes to Unity and seems he is part of one GDC session today. Maybe he will share some presentation material to us too (unless GDC passport exclusive)

http://schedule.gdconf.com/session/glnext-the-future-of-high-performance-graphics-presented-by-valve

 

It seems to have similar goals to what Metal did on iOS. I never really messed around with Metal, so I don't know if it lived up to the hype or not.

 

i doubt, you know, NDA and all that stuff...

btw very minor note on bloatware this isnt 100% true until Microsoft open source their DirectX so DirectX could be incorporated to SPIR-V too... but yes there should be definitely less bloatwares

 

What's DX got to do with Khronos API's? I suppose they might of had an NDA. Anyway explains why things are the way they are..

 

this SPIR-V is like IL in .NET but for drivers as i understand from simple text presentation https://www.khronos.org/registry/spir-v/papers/WhitePaper.pdf
as i understand if DirectX would be open source then drivers could have even lesser bloatwares. i didnt said u have 0% true

 

Here is the gist of it:

Under OpenGL:

Code (csharp):

1.  
2. Game   ----->  Driver -----> videocard
3.         GLSL          Instr
4.  

The game sends shaders written in GLSL to the driver. The driver parses and compiles them into video card instructions and sends them to the video card.
The parsing and compilation that the driver does is CPU intensive, complicated, and leads to subtle differences between vendors.

Under Vulkan:

Code (csharp):

1.  
2. Developer -----> Unity   --------> Game ------->  Driver ------>  videocard
3.            GLSL           SPIR-V         SPIR-V           Instr
4.  

You the developer write the shader in GLSL (or cg). Unity, or whatever development tool you are using will compile it into SPIR-V, which is a binary bytecode, similar to .net CLR but for shaders. You ship the game with the compiled shader. At Runtime, the game sends the SPIR-V to the driver, which converts it to video card instructions.

Compiling SPIR-V is a lot simpler than GLSL, so this should reduce the CPU overhead of draw calls as well as make drivers more consistent.

There are other improvements in the API such as thread support. There is no Vulkan ES, Vulkan is designed to work across all devices.

So Vulkan means for you lower CPU cost per draw call, which in most cases can result in higher fps than OpenGL.

My guess is that Vulkan will be adopted in Android first, since apple already has Metal which is a competitor, and Microsoft has DirectX 12.

 

I assume the main point is like with Mantle and DX12: the driver overhead is massively reduced, but the engine programmers have to handle all resource management themselves (so the driver does no longer try to handle that for you).

[Kind of like going from C# back to C++ because it is just more effective if you handle the resources yourself as long as you know what you do]

 

Apple, which has the Metal API, also has their logo on the Vulkan homepage.

I believe the Metal shading language, based on C++, uses LLVM. Vulkan will use SPIR-V, which also uses LLVM. It will be interesting to see the parallels between Metal and Vulkan. Both are said to be command-buffer based.

According to the sources, any device with OpenGL ES 3.1 support can also support Vulkan. Vulkan drivers are supposed to be leaner than OpenGL. I'm curious if graphics vendors will create Vulkan drivers for their older chips.

 

The development community has been clamoring for a less cluttered OpenGL for some time. For a while, OpenGL has bloated from the need to support older versions of the API. Vulkan sounds like it is a ground-up rebuild, and will likely excise all of the outdated code of the original OpenGL.

The focus of graphics has changed so much since the early days that a shift like this was inevitable. I find it encouraging that the Khronos group is speaking with all of the major interested parties in order to get feedback on the active development of the system. Sony took a similar approach when designing the PS4, and the results were very favorable.

 

Feedback from @Aras will be great. I remember reading somewhere that adding Metal support to Unity was relatively a straightforward process.

 

Very nice one, Valve:
http://tech.slashdot.org/story/15/0...open-source-intel-vulkan-gpu-driver-for-linux

 

In case anyone is interested in the (now-defunct) AMD Mantle API:

http://www.amd.com/Documents/Mantle-Programming-Guide-and-API-Reference.pdf

 

Mantle is now defunct? Didn't it just come out? I'm confused.

 

Well it"s About time they ditch the legacy opengl 1.0 code. But the average unity developer might not notice the difference since The graphic api is abstracted from developer.

 

Mantle is DOA (dead on arrival) since its feature set has been absorbed in Vulkan, but AMD decided to still share the specifications.

 

Some of the ideas in Mantle were so good that everyone else (Apple Metal, DX12, OpenGL) got in on the action before Mantle development was even fully opened up to the masses.

 

Interesting. Yeah I've been reading a little bit about it since then. Cool stuff.

 

We are involved with it's development (though not me). At GDC Unity showed off the core mine demo running using WebGL 2.0. Presumably it is Vulkan, but they didn't say specifically. It was just amazing though.

 

WebGL users OpenGL not Vulkan.

I would assume that at some point in the future if Vulkan is successful we will see a WebVulkan standard emerge, but it won't be backward compatible with WebGL.

 

Don't miss the talk about Vulkan:

 

Interesting. I misunderstood, I thought it was leveraging web/OpenGL Now I am more curious what unity's demo was.

 

Unity generates code is asm.js, which is a subset of javascript that browsers can optimize quite a bit.

The generated code accesses the graphics card using WebGL. WebGL is a standard api for javascript that browsers provide for using OpenGL inside your web page. So WebGL is very much tied to OpenGL.

Unity will support Vulkan at some point, but NOT for WebGL, only for your standalone apps. As of this writing, there is no way to access Vulkan from javascript in any browser.

The demo they had was running on WebGL (therefore OpenGL). The reason this is good, is that the customer will no longer need to download a plugin, he just opens the web page and the game starts. This demo in no way used Vulkan. The impressive thing about this demo is that performance was really good for a game written entirely in javascript. For the first time, it becomes viable to make games for the web in unity that don't require plugins.

At some point, if Vulkan gains marketshare, browsers should develop an api similar to WebGL but for Vulkan, i.e. WebVulkan. Then games in javascript will also be able to benefit from Vulkan.

 

That I get. I meant the 2.0 demo at GDC. Was that just a more optimized export? The alluded that it was a different tech than the current webgl export.

 

So, "Life Long and Prosper" Vulkan.

 

It's WebGL 2 that they showed which is a subset of OpenGL ES 3. But FF and Chrome use ANGLE to map that to DX9/11. WebGL is just OpenGL ES 2.

 

The faster load times, huge increase in allowed drawcalls, and things like faster shadowmapping will certainly be noticable.

 

I wonder if that'll help out their steam machines & attract developers to source engine 2.

That sounds super useful for mobile

 

From what I have seen in the Metal benchmarks for IOS it's nice. Though rumor from Carmack has Android using their own, which will not be good since we don't need any more fragmentation.

 

Maybe not, but you have to admit Carmack working on anything is exciting.

 

Oops, I didn't mean Carmack is working on it, he is the one that doesn't want it.

 

Oh I misread that. Well that's disappointing

Fragmentation, eh? Damn. Hopefully it's not as bad as the rift between open-gl and directx. I hate that directx is windows only, but damn, look at the difference in how many materials you can overlay with pbr shaders!

 

I think WebGL 2.0 will be the web browser equivalent OpenGL ES 3.0. Also from what I've read, all of the extensions in WebGL 1.0 (including floating point textures and multiple rendering targets) will be supported by default in WebGL 2.0.

 

So I don't see Vulkan on the roadmap for the next 9 months. I honestly can't see using OpenGL for my Linux port, so I'm hoping Vulkan support slips into Unity at some point so I can port to Linux. Any word from Unity staff on the state of Vulkan with Unity?

EDIT: Well maybe Unity 5.3 with OpenGL 4.x will work for the port. Still looking forward to Vulkan.

 

Vulkan isn't out yet.

 

Godot and Valve support vulkan. The will of GabeN.

 

If Unity were to put it on their roadmap, it would likely go in much the same location as the Linux port.

 

Any Unity updates on Vulkan as it sounds like some developers are saying it is better than DirectX 12?

 

At a Unite talk (can't remember which one, I watched it on YouTube), they mentioned to work on it as soon as it is available.

 

Not sure what's going on with Vulcan but Apple OSX Mavericks now runs on `Metal for Mac`, and the upgrade from the previous version did provide a noticeable speedup. Apple seems to like doing everything custom so I presume they are not going to support Vulcan as their core graphics tech.

 

The platforms on which Vulkan will be relevant as primary solution will most likely be the Linux ones including Android. I would be surprised if it was adapted by Apple at all.

 

Well if Vulkan makes an appearance this or early next year there are still a lot of windows users who have not upgraded to 10 and could benefit from the Vulkan API.

42% of steam users have a DX12 capable graphics card on a < Windows 10 OS.

It would be a shame if Apple did not support Vulkan as it could be a great cross technology platform for developers and game engines to work with.

 

Unfortunately that's the catch... if it makes an appearance. Khronos was never known for speed.

 

That's an interesting stat.

 

The thread gets old but today Vulkan 1.0 specifications were released :

https://www.khronos.org/news/press/khronos-releases-vulkan-1-0-specification

 

Will Unity announce Vulkan support at GDC ?

 

Wouldn't bet on it.

You'd need a driver support first. Although it seems that NVidia has it covered.
https://developer.nvidia.com/vulkan-driver

I think I'll need to take a closer look at this, since my hardware should be supported.

 

It should be interesting when it's available to test a complete game scene before and after using Vulkan new driver.