Detecting Pixel Colours On Screen

OpenGL OpenGL: Basic Coding
1

Hello,

I’m trying to create an application that needs to be able to do two things:

  1. Detect what colour each pixel is on a user’s screen.
  2. Change the colour if it falls within a certain colour range.

For example, if the user had a 2 pixel screen. I want to be able to poll the screen, have it return an array or some data object that says pixel 1 is: FFFFFF, and pixel 2 is: FFFF00. Assuming I had a rule that any low value of the last 2 digits was to be increased by 10, it would change Pixel 2 to: FFFF0A.

I was wondering if OpenGL has some clear ways of accomplishing these goals in close to real time. Some advice on to what libraries to use/readings/tutorials would be helpful. I have never worked with OpenGL before, but I am familiar with a large amount of programming languages. Java, C++, Swift, Python, Ruby on Rails, AngularJS.

Thanks in advance for your help!