Opengl 3.3 was simultaneously released with OpenGL 4.0. Why ? I don’t clear understand differences between these two version.
I don’t clear understand differences between these two version.
Did you, I don’t know, look?
You can consider OpenGL 3.3 to be the equivalent of DX10. OpenGL 4.x would be DX11.
At the top left side, go to Documentation and click on Specifications. Download the specifications (which are in pdf format)
At the end, you have Appendix sections and they detail what new features are added and what extension has been integrated into the Core.
…an OpenGL 3.3 specification, together with a set of ARB extensions, to enable as much OpenGL 4.0 functionality as possible on previous generation GPU hardware…