# Is it possible to achieve bloom/glow effect in VTK?

**URL:** https://discourse.vtk.org/t/is-it-possible-to-achieve-bloom-glow-effect-in-vtk/10438
**Category:** Support
**Created:** [January 13, 2023, 9:11am UTC](https://discourse.vtk.org/t/is-it-possible-to-achieve-bloom-glow-effect-in-vtk/10438 "2023-01-13T09:11:04Z")
**Posts on this page:** 1
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### Author: ![Paulo\_Carvalho](https://discourse.vtk.org/user_avatar/discourse.vtk.org/paulo_carvalho/32/370_2.png) [@Paulo\_Carvalho](https://discourse.vtk.org/u/Paulo_Carvalho)
#### Post date: [January 13, 2023, 9:07pm UTC](https://discourse.vtk.org/t/is-it-possible-to-achieve-bloom-glow-effect-in-vtk/10438/2 "2023-01-13T21:07:56Z")

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Hello,

I’m not aware of any simple VTK switch to turn on glow effect. But I can think of two approaches:

1. Working with the OpenGL buffers to post-process your rendered scene:

You can try this: [https://learnopengl.com/Advanced-Lighting/Bloom](https://learnopengl.com/Advanced-Lighting/Bloom) . These are, of course, direct OpenGL calls which, of course, require an OpenGL render window.

To use lower level OpenGL API with a VTK application, you can refer to: [https://discourse.vtk.org/t/how-to-use-original-opengl-in-vtk-program/4636](https://discourse.vtk.org/t/how-to-use-original-opengl-in-vtk-program/4636)

1. Writing a shader code and assigning it to your `vtkMapper`:

There is a simple example of a glow effect shader here: [https://lettier.github.io/3d-game-shaders-for-beginners/bloom.html](https://lettier.github.io/3d-game-shaders-for-beginners/bloom.html) .

To set a custom shader to a `vtkMapper` you can refer to this: [https://vtk.org/Wiki/Shaders\_In\_VTK](https://vtk.org/Wiki/Shaders_In_VTK).

best,

Paulo

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