Gamma correction

Scripting Issues
1

Hi,

Is there a way (or what is the way) in Panda to implement gamma correction? (for the whole scene)
Thanks.

2

That is possible by creating a postprocessing filter with a shader applied.

3

using a shader would be the most platform independant, but maybe not hardware? just wondering how this is could be done in for low-end gfx-cards. isnt applying a post effect shader a quite processing intensive method for such a task?

most probably there are driver/system interfaces for doing something like this. for example this page mentions such a interface for osx:
developer.apple.com/Mac/library/ … vices.html
however implementing this on a panda window may be pretty difficult…

4

I’m sure you could create a limited implementation by using a postprocessing filters without shaders, but using texture combine modes.

5

You can use base.win.getGsg().setGamma(value) to set the gamma correction function to t^(1/value). This uses a direct hook into the hardware table, and doesn’t rely on shader support. I believe this is currently implemented on Windows only.

David

6

Just for reference, if someone ever decides to implement it under Linux, it can be done using the XF86VidModeSetGamma function in the XFree86-VidModeExtension x11 extension.

7

note… setting the gamma under linux and not un-doing the changes can be quite annoying >.< wc3 did it and once it crashed it stayed like this for the entire desktop until rebooting.

8

Thanks, i tried it on windows and works fine.

9

The same problem happens on Windows–if Panda crashes hard while you’ve got the gamma set funny, the OS won’t set it back for you. It’s a problem in general. Panda will set it back automatically when you exit in any of the normal ways, including a Python exception; but if you get a segment fault or bus error, you’re done.

David