# How are world coordinates represented in the shader of VTK?

**URL:** https://discourse.vtk.org/t/how-are-world-coordinates-represented-in-the-shader-of-vtk/4740
**Category:** Support
**Created:** [November 27, 2020, 1:30am UTC](https://discourse.vtk.org/t/how-are-world-coordinates-represented-in-the-shader-of-vtk/4740 "2020-11-27T01:30:38Z")
**Posts on this page:** 2
**Page:** 1

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### Author: ![Jone7](https://discourse.vtk.org/letter_avatar_proxy/v4/letter/j/e36b37/32.png) [@Jone7](https://discourse.vtk.org/u/Jone7)
#### Post date: [November 27, 2020, 1:30am UTC](https://discourse.vtk.org/t/how-are-world-coordinates-represented-in-the-shader-of-vtk/4740/1 "2020-11-27T01:30:38Z")

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Since I want to do some lighting calculations in the Shader, I need the world coordinates of the light source, camera, and vertex, but when I modify the Shader, it seems that I can only get the view coordinates.Is there any way to get these world coordinates?  
I looked at some examples and couldn’t find the answer.  
Thank you.

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### Author: ![Jone7](https://discourse.vtk.org/letter_avatar_proxy/v4/letter/j/e36b37/32.png) [@Jone7](https://discourse.vtk.org/u/Jone7)
#### Post date: [November 27, 2020, 12:22pm UTC](https://discourse.vtk.org/t/how-are-world-coordinates-represented-in-the-shader-of-vtk/4740/2 "2020-11-27T12:22:50Z")

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Now I have sent the world coordinates of the light source and the camera to Shader. Now I want to know how to get the world coordinates of the fragment. Is there any way to get them?