OpenVR support integrated into Quakespasm.

Forked from Dominic Szablewski's (Phoboslab) Oculus modification of Quakespasm and utilizing the OpenVR C wrapper by Ben Newhouse.

• vr_enabled - 0: disabled, 1: enabled
• vr_crosshair - 0: disabled, 1: point, 2: laser sight
• vr_crosshair_size - Sets the diameter of the crosshair dot/laser from 1-32 pixels wide. Default 3.
• vr_crosshair_depth - Projection depth for the crosshair. Use 0 to automatically project on nearest wall/entity. Default 0.
• vr_crosshair_alpha - Sets the opacity for the crosshair dot/laser. Default 0.25.
• vr_aimmode - 1: Head Aiming, 2: Head Aiming + mouse pitch, 3: Mouse aiming, 4: Mouse aiming + mouse pitch, 5: Mouse aims, with YAW decoupled for limited area, 6: Mouse aims, with YAW decoupled for limited area and pitch decoupled completely. Default 1.
• vr_deadzone - Deadzone in degrees for vr_aimmode 5. Default 30.
• vr_viewkick- 0: disables viewkick on player damage/gun fire, 1: enable

• Comfort options (such as tunnel vision/FOV reduction)
• Motion controls