I think I’ve found a bug with SDL 2.0.8 (I will test with latest master at some point!) on Raspberry Pi (3) where VSync is always enabled regardless of SDL_GL_SetSwapInterval calls. However, my proof is a bit convoluted, with too many moving parts.
Does anyone know of a simple SDL GLES2 test program I can run at command line, that would test SDL_GL_SetSwapInterval on/off? Eg, something that outputs X frames as fast as it can, and I can see if it’s limited by the current display Hz or not?