Stefan Ullinger Hi, so here we go: GL_LINE_SMOOTH bad for business! ;) I checked the code within SDL_renderer_gl.c / GL_CreateRenderer(..) and have found the reason for blurred lines when using OpenGL. I have attached 2 images here. I don't know whether this has to be changed and I don't know if there is an option to turn it off/on...just wanted to say that with GL_LINE_SMOOTH enabled there is a difference when rendering with opengl compared to directx.