Category Archive : Headless opengl

2 Oct, 2012 | Nesida | Comments

Headless opengl

GitHub is home to over 50 million developers working together to host and review code, manage projects, and build software together. Work fast with our official CLI. Learn more. If nothing happens, download GitHub Desktop and try again.

If nothing happens, download Xcode and try again. If nothing happens, download the GitHub extension for Visual Studio and try again. It aspires to fully conform to the WebGL 1. Installing headless-gl on a supported platform is a snap using one of the prebuilt binaries.

Using npm run the command. And you are good to go! If your system is not supported, then please see the development section on how to configure your build environment. Patches to improve support are always welcome! Note [macOS only]: due to an inadvertant low-level breaking change in libuv's process handling code, this package doesn't return a gl context when running nodejs version A fix has been released in Node.

Other platforms are unaffected.

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In addition to all the usual WebGL methods, headless-gl exposes some custom extensions to make it easier to manage WebGL context resources in a server side environment:. This extension provides a mechanism to resize the drawing buffer of a WebGL context once it is created.

This canvas manipulation is not possible in headless-gl, since a headless context doesn't have a DOM or a canvas element associated to it. For long running jobs, garbage collection of contexts is often not fast enough. To prevent the system from becoming overloaded with unused contexts, you can force the system to reclaim a WebGL context immediately by calling.Visualization is a great tool for understanding large amounts of data, but transferring the data from an HPC system or from the cloud to a local workstation for analysis can be a painful experience.

Visualization tool developers increasingly support server-side rendering. Intelligent Light and Daimler AG use server-based pipelines to analyze the results of their large-scale vehicle simulations, as Figure 1 shows. Sifting through the 15 terabytes of data from this simulation is much more quickly done on the server that ran the simulation, after which the salient time steps can be extracted and used to visually communicate results.

Data analytics and machine learning tools such as MapD are also moving towards server-side visualization, demonstrating huge performance gains from accelerating the full server-side analytics pipeline. MapD scales their backend rendering across multi-GPU servers to deliver tens of frames per second with the It does, however, require some slight modifications to your OpenGL context management code using EGL functions, as described in a previous post.

Using EGL also requires you to link your application to different libraries. This post is about how to correctly link a modern OpenGL application. Over the years, the situation has changed and a wide range of display managers have emerged. People want to have Xbased display managers on the same system with Waylandor to use hardware-accelerated OpenGL on the same system with software-emulated OpenGL.

The separation of OpenGL functions and context management functions into separate libraries allows developers to build applications supporting multiple context creation mechanisms. For instance, this enables you to add an EGL backend to your glX-based application to deliver cloud-based rendering capabilities. You need to modify the context creation mechanism, as described in a previous postto initialize either glX or EGL. All the other rendering code remains the same. But now you need to link against libOpenGL.

Starting with version 3. Server-side rendering offers a range of advantages for large-scale visualization, including reduced data transfer cost, simplified application deployment and support for a wider client base. Toggle navigation Topics. Autonomous Machines. Autonomous Vehicles. Data Science. Tom has over 10 years experience in high-performance parallel visualization at a variety of institutions, from the University of New Hampshire UNHto multiple U. Tom graduated from UNH with a B.

View all posts by Tom Fogal. View all posts by Peter Messmer. Related posts. By Peter Messmer January 21, Hello - I have written a QT gui application that can also be run in a command-line server mode.

My workstation is configured for normal desktop gui usage and the application works fine when launched from the X desktop session, running the app in either gui mode or server mode.

But I want to optionally run my app remotely, from an ssh terminal, in its server mode. The qt app launches in my ssh session using the qt -platform offscreen arguments but can not initialize opengl. I am looking to get the full capabilities of OpenGL 4.

Is there some lower level config that will enable my app to run in this mode? My app decides based on its own command line args whether to display a gui or not. The app is doing opengl 4. I was only using the QT offscreen plugin to confirm whether I could get the app to launch at all.

If I run in the ssh terminal with the default QT platform plugin seems to be xcb I get this error:.

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Do I need to start a headless x server within that ssh session and then run my app? If so, can I do that without changing the behavior of the regular desktop x sessions that run on the same computer? What exactly does your app do when in server mode as compared to gui mode?

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I initialize OpenGL the same way in both modes, before any windows are created: Using QT for cross-platform context creation, I do a sequence like. The differences arise after this code has already run, in which I create a QMainWindow if in gui mode but not when in server mode. I was more interested in the usage patterns of gui and server mode. Would you be satisfied if gui mode worked from an ssh session?

This could be achieved with VirtualGL. Or are there other reasons for server mode? If I run in the ssh terminal with the default QT platform plugin seems to be xcb I get this error: qt. This application failed to start because no Qt platform plugin could be initialized. Reinstalling the application may fix this problem. Available platform plugins are: eglfs, linuxfb, minimal, minimalegl, offscreen, vnc, wayland-egl, wayland, wayland-xcomposite-egl, wayland-xcomposite-glx, xcb.

Then I do my own opengl api function pointer loading using the glad library.I recently had the idea of using the cloud for continuous integration of a graphics engine. This article is just a diary, in case my future self needs it.

headless opengl

In my notes, anything in blue italics is a placeholder and can be replaced with whatever string happens to be appropriate. The first thing I did is install the AWS command line interface and configure it with the proper security info. During the configure step, I chose text for the default output format to make it easy to stash the results of commands into variables.

It seems to have a September driver pre-installed. Its image id is in the snippet below. After creating the instance, I had to wait a minute or two for the machine to become available. I invoked the above describe-instances command a few times to check up on the status. Next, I wanted to do a bunch of yum install stuff so I quit the shell and created a script on my local machine. This is what I saw:. At this point, I figured I had a pretty decent development environment.

No more sudo commands from this point forward. Invoking the test caused X11 to complain about using RandR without a physical monitor.

headless opengl

Anyway, the X11 spew is harmless as far as I can tell. Next, I copied over the screenshot and opened the image on my local machine. To my dismay the screenshot was an empty image! To fix this, I had to modify my graphics test to render to an FBO instead of the backbuffer. Interestingly, this seems necessary in an X11 environment but not in a OS X environment.

headless opengl

Anyway, the final step was termination of the instance, to avoid paying Amazon even more than I already do:. So, I cloned the instance to create my very own AMI, then killed off the prototype.By using our site, you acknowledge that you have read and understand our Cookie PolicyPrivacy Policyand our Terms of Service.

Stack Overflow for Teams is a private, secure spot for you and your coworkers to find and share information. Or is it just some intricacy in PyOpenGL? I tried to find some information on how to initialize GL context on a headless and virtualized machine, no luck. Any information on these topics is appreciated.

Most of the options at VJovic's link aren't hardware accelerated and all of them are deprecated in favor of the OpenGL Framebuffer Object extension Notice the date: ! Also, offscreen rendering isn't the whole solution, as Calvin noted, you need an openGL context except for OSMesa, which uses software rendering.

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Our research lab has been doing headless opengl rendering for about a year you can see my related serverfault question hereand we found that the easiest thing was to just give users remote access to the server's local X-screen.

The downsides: a giving remote access to the x-server is regarded by some as a bad security practice if done wrong, and b it opens a dummy window will pop up on the server's display, but if it's headless, this shouldn't matter. A few other options are described in the ServerFault link too, if you're interested. You need an x-screen running on the server, and it should be noted that some video cards require a physical monitor to be attached if you want to start an x-screen.

The NVidia driver lets you get around this using the ConnectedMonitor option in xorg. Another option I've used in the past is to the build a dummy monitor plug. There are probably other solutions.

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I experimented with this and yes, it appears that you can. I managed to get it working under Docker. Note that this only allows software rendering - while it might be good enough for my project, it might not be for yours. You can do off-screen rendering. More about it here. It depends what is supported by your graphical card and the OS. If you got old graphical chip, you can use mesa OS library but you get software rendering.

If it is newer, you can use pbuffers. If you setup the error callbacks in gluTessCallback see red book it probably will not call glGetError. GLU requires a valid openGL context, yes even if it should be possible to call the tesselator alone withoug a context. If you don't have a window, it should be possible - but hard. See the opengl wiki and read it 3 times, it's quite hard to follow. The basic idea is that you need a special extension to create your special, window-less context.

But to be able to call it, you have to have a context in the first place! I have whoever created this api. So create a context the usual way and hope that it works even it you don't have a screenget your extension, call wglCreateContextAttribsARB. Note : the extension spec says that When this extension is supported, calling wglCreateContext hdc is equivalent to calling wglCreateContextAttribs hdc,0,NULLso maybe, maybe you could bet along with a simple context creation.

Learn more. Ask Question. Asked 9 years, 4 months ago. Active 1 year, 11 months ago.It has been a long time indeed since my last entry here.

But I have actually been quite busy on a new adventure: graphics driver development. Two years ago I started contributing to Mesamostly to the Intel i backend, as a member of the Igalia Graphics Team. During this time I have been building my knowledge around GPU driver development, the different parts of the Linux graphics stack, its different projects, tools, and the developer communities around them.

But today I want to start a series of articles discussing basic examples of how to do cool things with the Khronos APIs and the Linux graphics stack. It will be a collection of short and concise programs that achieve a concrete goal, pretty much what I wish existed when I looked myself up for them in the public domain.

If you, like me, are the kind of person that learns by doing, growing existing examples; then I hope you will find this series interesting, and also encouraging to write your own examples. Before finishing this sort of introduction and before we enter into the matter, I want to leave my stance on what I consider a good minimal example program, because I think it will be useful for this and future examples, to help the reader understand what to expect and how are they different from similar code found online.

That said, not all examples in the series will be minimal, though. Ok, now we are ready to move to the first example in this series: the simplest way to embed and run an OpenGL-ES compute shader in your C program on Linux, without the need of any GUI window or connection to the X or Wayland server. In modern distros, this access is typically granted by being member of the video group.

It can also be checked-up on my gpu-playground repository. See below for a quick explanation of its most interesting parts. The first two parts are the most relevant to the purpose of this article, since they allow our program to run without requiring a window system.

The rest is standard OpenGL code to setup and execute a compute shader, which is out of scope for this example. During Linux kernel 3. If you want to know more about render-nodes, there is a section about it in the Linux Kernel documentation and also a brief explanation on Wikipedia. The first step is to open the render-node file for reading and writing.

It may be different on other systems, and any serious code would want to detect and select the appropiate render node file first.

It is the render-node interface that ultimately allows us to use the GPU for computing only, from an unprivileged program. This is the most interesting line of code in this section.

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Setting up a compute shader and dispatching it should be uncontroversial, so we leave it out of this article for simplicity. Ok, with around lines of code we were able to dispatch a useless compute shader program. Here are some basic ideas on how to grow this example to do something useful:. And also implement some cool routine in the shader that does something interesting. With this example I tried to demonstrate how easy is to exploit the capabilities of modern GPUs for general purpose computing.

Does your application have routines that could potentially be moved to an GLSL compute program? I would love to hear about it. Skip to content It has been a long time indeed since my last entry here. A minimal example should: provide as minimum boilerplate as possible. Following the code flow across multiple files adds mental overhead.

The reader should not need to install stuff that are not strictly necessary to try the example. What next? Here are some basic ideas on how to grow this example to do something useful: Dynamically detect and select among the different render-node interfaces available.I have actually already referred 2 people to your company as after seeing our vacation pictures, they now want to see Iceland for themselves. A wonderful route to experience the diverse and wild beauty of Iceland, marvel at the birds and horses, get a taste of its history and culture and enjoy warm hospitality.

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The scenery and natural features were exceptional and so accessible although I don't think Nordic Visitor can claim credit for that. We got very lucky with the car being upgraded for free as this made a massive difference to our driving comfort.

Example: Run a headless OpenGL (ES) compute shader via DRM render-nodes

We also got very lucky in that my dive tour of Silfra was private. I was the only diver with 3 dive masters. Overall we had an exceptional trip and were very impressed with Iceland, its culture, its people, its beer and its Geology. We hope to come back. Thanks Arnar, you did a brilliant job and good luck learning to dive. Once again many thanks. The itinerary and road map provided by Nordic Visitor were perfect. Things to see along the way were clearly marked.

Pro Tip: Linking OpenGL for Server-Side Rendering

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