So I naively thought any SDL call shares everything with OpenGL, then I tried to set the viewport (via openGL call) to draw in a given corner only and then call SDL_RenderFillRect only to find out I needed to call SDL_RenderSetViewport.
In the past I largely only used SDL for sound and input while just using plain openGL calls. I now want to use SDL for text, reading image files to load as textures and drawing off screen. It’s been a while since I used OpenGL, so there’s a bit of relearning on my part.
My question is, with regards to buffers, matrix and other related items; where does SDL do it’s own thing independent of OpenGL (as I encountered with viewport) and where can I use either.