The canonical 3D API of the 1990s was OpenGL. This had been written by SGI and initially closely matched the capabilities of their workstation systems, operating as a hardware abstraction layer. The OpenGL API consisted mostly of state-setting instructions for setting up drawing modes like the paint color or camera position, and system for sending geometry into the system, normally as meshes of triangles. The combination of these instructions was saved into a display list which was then rendered to produce the output.