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Introduction

This article was written for Racer v0.9.0RC7, where the Oculus Rift Development Kit glasses are supported. The future consumer edition may prove to require changes though; this article just explains how to get it working in Racer as it stands.

The development kit comes with a 1280x800 display.

There is a fully configured version of Racer v0.9.0.RC7 here (150Mb).

Getting the Rift to work in Racer takes a bit of work, as it is not supported natively with a nice user interface around it. Here are the steps you need to take:

• First, unzip the default install of v0.9.0RC7 (later versions should also work, but may require small adjustments to this process).
• Make a copy of this installation, so you can create an Oculus Rift version (just copy the full directory).
• Set racer.ini's fs_filter1 setting to oculus_rift_f.cg (this file is located in data/renderer/fullscreen_shaders_hdr). This Cg shader does the distortion, optional chromatic abberation correction and such, required for the Rift's optical distortions.
• Set resolution.stereo.quad_buffered to 0 (this is the default).
• Set renderer.stereo.oculus_rift.enable to 1.
• Set renderer.motion_blur.fbo_width to 1096 (this 1.71x 640) - the bigger rendering area (offscreen) is used to avoid filtering pixels near the center of the lens, which can make things blurrier and give more aliasing artifacts.
• Set renderer.motion_blur.fbo_height to 1368 (1.71x 800).
  
• Set resolution.width to 1280, and resolution.height to 800. Also set resolution.fullscreen to 1.
  
• Set resolution.vsync to 1. Horizontal tearing will decrease immersion.
  
• Now you need to manually add an Oculus controller, to get head tracking going. The specific controls file (located in data/controls/) is set in racer.ini's ini.controls setting. By default this is set to profile1.ini, which means data/controls/profile1.ini is loaded. Open that file in a text editor.
• You will find a mouse and keyboard controller in that file. Add a controller, mimicking the syntax for the keyboard controller for example, so you get something like this (the additional text is marked in bold):

  global
  {
    free_shifting=0
    name=Racer controls - defined ingame by menu
  }
  controllers
  {
    oculus_rift
    {
      enable=1
      time_per_update_in=1
      time_per_update_out=10
      ; Latency correction (in seconds)
      prediction_time=0.06
      head_tracking
      {
        enable=1
      }
    }
    mouse
    {
  ...
  }    

   

• Make sure the Rift is the primary monitor for vsync to work. If you duplicate/clone your desktop monitor with the Rift's display, one of the two displays will be 'leading' when using vsync. Make sure the Oculus Rift is vsyncing correctly; if not, try making it the Primary monitor and cloning the Rift's display to your desktop monitor (this worked for me).
  

Live parameter tuning

While Racer is running, you can modify the system setting 'scenegraph.renderer.eye_distance' to modify the eye separation. Somehow currently it seems you may need something like 0.01 (instead of an expected 0.06 for 6 cm) to keep it together.

Also, you can use the system to tune the latency prediction by commands as 'set controllers.oculus_rift.prediction_time 0.06'. Try values between 0 and 0.1; more will become jittery and not nice to the brain!

Notes

Note that future Rift models may require shader changes (lens center etc). Currently these are hardcoded in the fullscreen shader (oculus_rift_f.cg).

Hopefully the Rift's future will see improved resolution (2 or 3-fold at least) and positional tracking.

(last updated May 24, 2013 )