# What's the difference between these OffScreen modes in VTK: SetOffScreenRendering; VTK\_USE\_OFFSCREEN\_EGL; GLEW\_OSMESA;

**URL:** https://discourse.vtk.org/t/whats-the-difference-between-these-offscreen-modes-in-vtk-setoffscreenrendering-vtk-use-offscreen-egl-glew-osmesa/11807
**Category:** Support
**Created:** [June 25, 2023, 2:40am UTC](https://discourse.vtk.org/t/whats-the-difference-between-these-offscreen-modes-in-vtk-setoffscreenrendering-vtk-use-offscreen-egl-glew-osmesa/11807 "2023-06-25T02:40:10Z")
**Posts on this page:** 3
**Page:** 1

<div class="post-metadata">

### Author: ![gpu](https://discourse.vtk.org/letter_avatar_proxy/v4/letter/g/e47c2d/32.png) [@gpu](https://discourse.vtk.org/u/gpu)
#### Post date: [June 25, 2023, 2:40am UTC](https://discourse.vtk.org/t/whats-the-difference-between-these-offscreen-modes-in-vtk-setoffscreenrendering-vtk-use-offscreen-egl-glew-osmesa/11807/1 "2023-06-25T02:40:11Z")

</div>

What’s the difference between these OffScreen modes in VTK:  
SetOffScreenRendering;  
VTK\_USE\_OFFSCREEN\_EGL;  
GLEW\_OSMESA;  
What’s the advantage and disadvantage?  
What’s their usage scenario?

---

<div class="post-metadata">

### Author: ![mwestphal](https://discourse.vtk.org/user_avatar/discourse.vtk.org/mwestphal/32/19_2.png) [@mwestphal](https://discourse.vtk.org/u/mwestphal)
#### Post date: [June 28, 2023, 7:33am UTC](https://discourse.vtk.org/t/whats-the-difference-between-these-offscreen-modes-in-vtk-setoffscreenrendering-vtk-use-offscreen-egl-glew-osmesa/11807/2 "2023-06-28T07:33:08Z")

</div>

> [@gpu](#):
>
> SetOffScreenRendering

Render offscreen, still need OpenGL and a graphic env, but the window will not appear. Great for testing.

> VTK\_USE\_OFFSCREEN\_EGL

Deprecated unused C++ definition

> GLEW\_OSMESA

A Glew definition, unrelated to VTK

More info about the actual feature here (from ParaView doc, but concepts are similar):

[https://kitware.github.io/paraview-docs/latest/cxx/Offscreen.html](https://kitware.github.io/paraview-docs/latest/cxx/Offscreen.html)

---

<div class="post-metadata">

### Author: ![gpu](https://discourse.vtk.org/letter_avatar_proxy/v4/letter/g/e47c2d/32.png) [@gpu](https://discourse.vtk.org/u/gpu)
#### Post date: [June 29, 2023, 3:18am UTC](https://discourse.vtk.org/t/whats-the-difference-between-these-offscreen-modes-in-vtk-setoffscreenrendering-vtk-use-offscreen-egl-glew-osmesa/11807/3 "2023-06-29T03:18:28Z")

</div>

thanks