Which is better for starting to learn graphics programming, DirectX or OpenGl ?
if I don't mistake, with DirectX you are limited to windows only
seamiki thanks for your answer. So OpenGl will be more appropriate when working with other operating systems ?
DirectX is easier but worse and restricted to Microsoft. OpenGL is much harder but also runs faster.
I think the understanding of computer graphics principles is a good place to start https://www.amazon.com/Computer-Graphics-Through-OpenGL-Experiments-ebook/dp/B00L2EBLKG/ As opengl is used on more platforms than directx I would go with opengl. Learning Modern 3D Graphics Programming - this course is very good AND FREE ! http://opengl.datenwolf.net/gltut/html/index.html