Explanation how opengl render 3D to 2D and how to get information about the object


Sorry for my english, it is not my mother language :slight_smile:

I am new to OpenGL and i am asking some question about how it’s work.
when rendering object Opengl recompute the vertex of the shader to reconstruct in 2D the object on a 2D space.

  1. so i am wondering is OpenGL reconstruct all the object or only the one how fit in the ProjectionView. Which in my point of view wiould cost less work but need to do some work to define which one fit in the ProjectionView or not.

  2. Than i would like to know if Opengl apply a number to all the shared displayed, even in drawArray method. And how to get those infmrmation.

  3. there is the object in the world and the one displayed. It ispossible to get the number, id, of them.

As i am starting in Opengl i fell that it is the minimum to anderstand. To anderstand how OpenGL work.

Thanks in advance you your help.

hi ther,

when you start opengl you may have many questions.
maybe you wanne get some basic information here:

Or maybe satrt here: