Q&A with the developers of rFactor – Joe
By John Bayley – Product Development…
So much of rFactor seems to be built around a number of new technologies. One important new technology is most certainly its graphics engine, gMotor2. Not only was I curious about its capabilities and features, but also what this could mean to modders. The driving force behind gMotor2 is Joe Campana.
What can you tell us about the gMotor2 graphics engine used in rFactor?
gMotor2 is our DX9 engine, all new and making its debut in rFactor. It took me almost a year of non-stop typing. There is support for a wide range of video hardware, from fixed function DX7 to shader-based Dx8/Dx9 GPUs. Some of the gM2 features you’ll see in rFactor are lots of dynamic shadows, active lighting for accurate time-of-day, and night driving with dynamic track lights and real headlights.
Tell us more about the time-of-day feature.
The time-of-day feature means that you can setup your race session to start at any time of day or night, and time marches forward from that point, in real-time or at an accelerated rate if you want to speed through the day-night and night-day transitions. As time progresses, you’ll see accurate changes in lighting, shadows, and skies. Circuit builders will even be able to include latitude/longitude and date information into the track description for complete real-world accuracy.
As the day gets later, the sun will set, shadows grow longer, and at some point the track lights will come on. The driver can turn on headlights when it gets too dark, the AI drivers will do this too. If you drive through the night, things will start to brighten up as the sun rises, shadows shorten up, and eventually the track lights turn off. Again, this can all happen at an accelerated rate so you don’t have to drive for 12 hours to see the effects (unless you want to).
This sounds pretty CPU intensive. Does this limit the number of polygons used in cars and tracks?
Not really. Modders should of course use as few triangles as possible for tracks and cars, but the real limits are video memory. A mod which requires 200 MB of video RAM will run fine on a card with that much memory, but won’t run on cards with less RAM. Creation of complete LOD chains, particularly for car models, is critical for mods meant to run across a wide range of hardware.
I’ve worked on some mods myself in the past for your previous products. Can I convert or reuse them?
rFactor supports gMotor2-format assets only. We really encourage modders to work from original source assets, and use our tools (or tools created from the Export SDK) to create gMotor2 assets. Previously created assets will probably produce less then optimal results.
How do you think this engine compares to your previous efforts, and to others that are currently available?
It’s been a long time since I’ve been able to make this kind of foundation change, so I’ve been able to incorporate lots of new concepts and technology into the engine. The raw engine itself is amazingly fast, but making a real game engine is also about providing tools to asset builders, and exposing technology to game designers while keeping things accessible to mod makers. So compromises are necessary to make their world better, but even so, this engine is our best yet, and only getting better.
Well, from what I’ve seen so far, it’s more than doing the job, and quite impressively…