FUCKING OPENGL

So I'm supposed to draw an adjustable circle "By using only the put_pixel (or set_pixel or similar) function of the graphics toolset (such as GL)"

BUT THERE IS NO WAY TO PUT A SINGLE PIXEL IN THE GOD DAMN FUCKING LIBRARY? WHAT THE FUCK DO I DO?

in before use 1px large rectangles

The most flexible option:

1. Make a single glRect that spans the entire screen
2. Apply a single texture to this screen, with one texel for each pixel
3. Using your own libraries and routines, blit objects and perform raycasts, with the output on the texture
4. To remind the user that they are using an OpenGL application, rotate the rectangle from time to time