Survey about updating minimum OpenGL version to 4.1

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We’re proposing to bump the minimum OpenGL version from 3.2 to 4.1. As VTK uses a core profile context and asks for the highest available version from the OS, chances are you’re already using 4.6. Please let us know if your team requires VTK to support GPUs with OpenGL 4.0 or lower. We could look into the use case if needed and make necessary updates.

This backward compatibility is starting to hamper the introduction of newer robust rendering capabilities like tessellation shaders, compute shaders, etc. In the future, VTK will move over to WebGPU, however, that is a long term goal, best discussed in another post.

Here are some resources to get the general idea of systems supporting OpenGL 4.1

  1. https://developer.apple.com/opengl/OpenGL-Capabilities-Tables.pdf (pg 34 onwards)
  2. https://www.phoronix.com/news/Zink-OpenGL-4.1-Mesa-21.0
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Rational for choosing 4.1 instead of a newer version[1]:

  • macOS only supports up to 4.1[2]
  • Mesa 12 onward support OpenGL 4.3 (Ubuntu 20.04 has mesa 21.2.6, Debian 10 has 18.3.6, many distributions considered ‘old’ have a mesa version > 18.)

For more details, see https://gitlab.kitware.com/vtk/vtk/-/issues/19291

  1. History of OpenGL - OpenGL Wiki ↩︎

  2. c++ - Develop using OpenGL 4.x on OSX Big Sur - Stack Overflow ↩︎

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Will the bump to OpenGL 4.1 allow for delegating “High Order” solution tesselation and rendering directly to the GPU ? When is the switch planned ? VTK 9.4 ?

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Yea. VTK already does the tessellation of a new dataobject subclass called vtkCellGrid on the GPU. The switch could be done by 9.4

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