specifications.md

Specifications for the Original Quake (idTech 2) Engine

Coordinate Systems

Quake's coordinate system specifies its axes as follows:

• The x-axis specifies depth.
• The y-axis specifies width.
• The z-axis specifies height.

This contrasts with the OpenGL coordinate system, in which:

• The x-axis specifies width.
• The y-axis specifies height.
• The z-axis specifies depth (inverted).

Thus, to convert between the coordinate systems:

      x <-> -z
Quake y <->  x OpenGL
      z <->  y

       x <->  y
OpenGL y <->  z Quake
       z <-> -x