Which 3D coordinate system OpenGL uses?

Does OpenGL uses left-handed or right-handed
coordinate system?
I don’t now where the positive x side is.

I believe OpenGL uses a positive X to the left, positive Z into the screen and a positive Y going up. At least this is the original orientation prior to moving your camera.

What I do is use my own coordinate system for all my calculations then modify them to OGL’s system for display.


OpenGL uses a right-handed coordinate system, with positive x to the right, positive y up and positive z comes out of the screen.

Thank You.You really helped to me.
I read in OpenGL books that in graphics usaually left-handed system is used,so I
wasted a hole day to understand what is
going on with my inverse coordinates.

In fact, the OpenGL design leaves the choice to the user. It’s written into the specification.

With that said, imagine you have written your program in right-handed coordinate space, you can switch to left-handed very easily with a scale. Take a look at the FAQ .