The opengl default reference (eye) coordinate system is: the origin is at the center of the window,Z-axis points out of the screen, X-axis points to the right,and Y is up. All coordinate transformation is based on this coordinate system. Is there any way to redefine this reference frame. Thank.
OpenGL coordinate system is right-handed by default and can’t be changed. Direct3D lets you choose right-handed or left-handed coordinate system.
… unless you multiply your modelviewmatrix to convert between coordinate systems.
M=[ 1 0 0 0
0 1 0 0
0 0 -1 0
0 0 0 1 ]
will invert the z-axis so the camera is effectively looking down the +Z axix.