small error section 3.2.6 - Varying color

[jabarragann]

Hi all,

I think there is an error on the fragment shader program of section 3.2.6. It should be using the previously declared variable "v_color" not "color"

[jabarragann]

Just realized that #49 also pointed out the same mistake. However, when I tried to do the PR as you requested, I was not able to find the error on the source code. Both the book.html and the 03-quickstart.rst file don't have this error.

The error is only appearing in the book version in https://www.labri.fr/perso/nrougier/python-opengl/#varying-color.

So it might be fixed by uploading a newer version. (Not exactly sure of how to book is generated from source)

I can help you out doing the PR if you think there is any other file that needs to be changed.

[rougier]

Thanks for the report. It may have been already corrected but the website is not up to date with GitHub soures (I have to built it manually).