I want to write application for digital signage but I want it to run in minimal environment so I don't want X11 server. Is it possible to run on one account OpenGl app without X11 (or any other graphic drawing library with at least 2D graphics)?
One way is via the Mesa off-screen rendering API. Be aware that this will most likely be unaccelerated.
If you just don't want X11 and you're willing to use OpenGL ES then Wayland and corresponding Gallium drivers would get you hardware acceleration.
I`m working in a very similar project. Since for me the need to run opengl without xserver was primarily performance based, I opeted instead to install damn small linux to a flash drive along with the program i wrote. Damn small linux is super small (50 mb for the entire os), and since its designed to run on low spec hardware (it can be run on a pentium 1 with 16 mb of ram) it uses a minimal ammount of system resources. I just run ny application on top of damn small linux, and it performs extremely well.
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I display a 2D texture in OpenGL using Qt.
Unfortunately I have found out that I need to support running my application via Remote Desktop to a Windows 7 PC. In this case I need to use OpenGL ES 2.0 API (ANGLE).
Due to low bandwidth my 2D visualization seems to be lagging.
My texture may have higher resolution than the screen so that it needs to be minified.
When not using remote desktop my approach have been to specify a very detailed texture and let the graphics card do the minification.
However now I am thinking that the OpenGL calls are executed in software locally and not on the remote machine? In which case the textures have to be transmitted via TCP/IP?
Does this mean that I should do minification myself before using the textures?
As an example instead of using a 2048x2048 texture I may bin 2x2 pixels in C++ and upload a 1024x1024 texture.
Alternatively I could use glGenerateMipmap?
I feel multiple terms are confused here: RDP just transfers the entire remote desktop for you whatever is on it, so no "OpenGL calls are executed in software locally". Hence, unfortunately it will not help if you reduce the texture size in your app, even if you remove it entirely (try it). RDP is not really suitable for real time animation.
Your app better be running locally on the user machine, so better to think how to distribute your OGL app to users.
If you cannot install your app on users machine, or give them installation kit, then
maybe turning your app to a browser app is a better option.
WebGL there for exactly this kind of applications, and is a standard too:
https://www.khronos.org/webgl/
This should be straightforward, but for some reason I can't make it work.
I hired a Softlayer Bare Metal Server that comes with an Nvidea Tesla GPU.
I'm remotley executing a program (openScad) that needs OpenGL > 2.0 in order to properly export a PNG file.
When I invoke openScad and export a model, I get a 0kb png file as output, a clear symptom that OpenGL > 2.0 support is not present.
In order to make sure that I was running openGL > 2.0 I connected to my server via RD and ran GlView. To my surprise I saw that the server was supporting nothing but openGL 1.1.
After a little research I found out that for standard RD sessions the GPU is not used so it makes sense that I'm only seeing openGL 1.1.
The problem is that when I execute openscad remotley, it seems that the GPU is not used either.
What can I do to successfully make the GPU capabilities of my server work when I invoke openscad remotely?
PS: I checked with softlayer support and they are not taking any responsibility
Most (currently all) OpenGL implementations that use a GPU assume that there's a display system of some sort using that GPU; in the case of Windows that would be GDI. However on a headless server Windows usually doesn't start the GDI on the GPU but uses some framebuffer.
The NVidia Tesla GPUs are marketed as compute-only-devices and hence their driver does not support any graphics functionality (note that this is a marketing limitation implemented in software, as the silicon is perfectly capable of doing graphics). Or in other words: If you can implement your graphics operations using CUDA or OpenCL, then you can use it to generate pictures. Otherwise (i.e. for OpenGL or Direct3D) it's useless.
Note that NVidia is marketing their "GRID" products for remote/cloud rendering.
I'm replying because i faced a similar problem in the past; also trying to run an application that needed openGL 4 on a windows server.
windows remote desktop indeed doesn't trigger opengl. However if you use tigervnc instead and then start your openScad application it might recognize your opengl drivers. At least this trick did it for me.
(when opening an openGL context in a program it scan's for monitors/RD's attached i pressume).
hope it helps.
I want to implement an opengl application which generates images and I view the image via a webpage.
the application is intended to run on a linux server which has no display, no x windows, but with gpu.
I know that egl can use pixmap or pbuffer as render targets.
but the function eglGetDisplay worries me, it sounds like I still need to have attached display to make it work?
does egl work without display and xwindows or wayland?
This is a recurring question. TL;DR: With the current Linux graphics driver model it is impossible to use the GPU with traditional drivers without running a X server. If the GPU is supported by KMS+DRM+DRI you can do it. (EDIT:) Also in 2016 Nvidia finally introduced truly headless OpenGL support in their drivers through EGL.
The long story is, that technically GPUs are perfectly capable of rendering to an offscreen buffer without a display being attached or a graphics server running. However due to the history of graphics driver and environment development this is not possible, yet has not been possible for a long time. The assumption back then (when graphics was first introduced to Linux) was: "The graphics device is there to deliver a picture to a screen." That a graphics card could be used as an accelerating coprocessor was not even a figment of an idea.
Add to this, that until a few years ago, the Linux kernel itself had no idea how to talk to graphics devices (other than a dumb framebuffer somewhere in the system's address space). The X server was what talked to GPUs, so you needed that to run. And the first X server developers made the assumption that there is a person between keyboard and chair.
So what are your options:
Short term, if you're using a NVidia GPU: Just start an X server. You don't need a full blown desktop environment. You can even save yourself the trouble of starting a window manager. Just have the X server claim the VT and being active. There is now support for headless OpenGL contexts through EGL in the Nvidia drivers.
If you're using an AMD or Intel GPU you can talk directly to it. Either through EGL or using KMS (Google for something called kmscube, when trying it, make sure you switch away from your X server to a text VT first, otherwise you'll crash the X server). I've not tried it yet, but it should be possible to adjust the kmscube example that it uses the GPU to render into an offscreen buffer, without switching the VT to graphics mode or have any graphics output on the display framebuffer at all.
As datenwolf told u can create a frame buffer without using x with AMD and intel GPU. since iam using AMD graphics card with EGL and iam able to create a frame buffer and iam drawing on it.with Mesa Library by configuring without x u can achieve.
I have an algorithem that runs on PC and uses OpenCV remap. It is slow and I need to run it on an embedded system (for example a device such as this: http://www.hardkernel.com/main/products/prdt_info.php
It has OpenGL 3.0 and I am wondering if it is possible to write code in OpenGL shader to do the remapping (OpenCV remapping).
I have another device that has OpenGL 2.0, Can that device do shader programming?
where can I learn about shader programming in OpenGL?
I am using Linux.
Edit 1
The code runs on a PC and it takes around 1min, On am embedded system it takes around 2 hours!
I need to run it on an embedded system and for that reason I think to use OpenGL or OpenCL (the board has OpenCL 1.1 driver).
What is the best option for this? Can I use OpenGl 2 or OpenGL3?
A PC with a good graphic card (compatible with OpenCV) is much faster than a little embedded PC like Odroid or Banana Pi. I mean that computational_power/price or computational_power/energy is lower on these platforms.
If your algorithm is slow:
Are you sure your graphic driver is correctly configured to support OpenCV?
Try to improve your algorithm. On a current PC, is easy to get 1TFLOP with OpenCL, so if your program really require more, you should think about computer clouds and such. Check that you configured the appropriate buffers type, etc.
OpenGL 3 allow general shaders, but OpenGL 2 is very different and it must be much harder or impossible to make your algorithm compatible.
To learn OpenGL/GLSL, be very care because most page learn bad/old code.
I recommend you a good book, like: http://www.amazon.com/OpenGL-Shading-Language-Cookbook-Edition/dp/1782167021/ref=dp_ob_title_bk
EDIT 1
OpenGL 3+, or OpenGL ES 3+ have general purpose shaders and may be used for fast computing. So yes, you will get performance increased. But graphic cards on these platform are very small/slow (usually less than 10 cores). Do not expect to get the same 1min-result on this ODROID than on your PC with 500-2000 GPU cores.
OpenGL 2 has fixed pipeline and it is hard to use it for parallel computing.
If you really require to use an embedded platform, maybe you may use a cloud of them?
I have hit a brick wall and I wonder if someone here can help. My program opens an OpenGL surface for very minor rendering needs. It seems on the MacbookPro this causes the graphics card driver to switch the hybrid card from low performance intel graphics to high performance AMD ATI graphics.
This causes me problems as there seems to be an issue with the AMD driver and putting the Mac to sleep, but also it drains the battery unnecessarily fast. I only need OpenGL to create a static 3D image on occasion, I do not require a fast frame rate!
Is there a way in a Cocoa app to prevent OpenGL switching a hybrid graphics card into performance mode?
The relevant documentation for this is QA1734, “Allowing OpenGL applications to utilize the integrated GPU”:
… On OS X 10.6 and earlier, you are not allowed to choose to run on the integrated GPU instead. …
On OS X 10.7 and later, there is a new attribute called NSSupportsAutomaticGraphicsSwitching. To allow your OpenGL application to utilize the integrated GPU, you must add in the Info.plist of your application this key with a Boolean value of true…
So you can only do this on Lion, and “only … on the dual-GPU MacBook Pros that were shipped Early 2011 and after.”
There are a couple of other important caveats:
Additionally, you must make sure that your application works correctly with multiple GPUs or else the system may continue forcing your application to use the discrete GPU. TN2229 Supporting Multiple GPUs on Mac OS X discusses in detail the required steps that you need to follow.
and:
Features that are available on the discrete GPU may not be available on the integrated GPU. You must check that features you desire to use exist on the GPU you are using. For a complete listing of supported features by GPU class, please see: OpenGL Capabilities Tables.