Adshir: Ray Tracing with LocalRay for the Mobile Gaming

Ray tracing is a computer graphics technique generating physically accurate photo-realistic images. Until 2018 ray tracing was implemented offline only, mainly in the film industry. There has been a long felt need for real-time and low-cost ray tracing, which is one of the most computationally complex applications.

Millions of rays are seeking a hit among millions of polygons, performing massive amounts of intersection tests. These tests, the most time-consuming task in ray tracing, are assisted by traversals of a huge accelerating data structure, which needs to be reconstructed upon major scene and geometry changes caused by skin animation. 

Real time performance has been achieved in 2018 by Nvidia RTX taking a single ray-per-pixel and an AI denoiser approach coupled with a hybrid architecture and dedicated hardware cores. Nvidia’s powerful GPU is supported by ray tracing accelerating hardware. Its high-power and high-cost target high-end computing platforms, excluding any type of battery powered device, and more specifically – smartphone/mobile devices.

Ray tracing for mobile devices was long considered as impossible due to their limited power, thin integrated-GPU sharing memory with CPU cores, reduced memory, and diminished memory bandwidth.

However, the huge volume of the mobile gaming market, exceeding the aggregated PC and console markets, strongly appeals for the cinematic level in gaming, comparable to that of high-end. Mobile gaming was the largest market segment and the fastest growing in 2019, projected to $106 billion in 2021 (source: Statista).

The yearned for targeted ray tracing in mobile devices was achieved simultaneously with RTX but rather quietly. “Adshir revealed the impossible: a software-based, cross platform real-time ray tracing running on a tablet” (Jon Peddie, GfxSpeak, Aug. 2018).

The software-only approach of Adshir assures continuity with standard GPUs, an APU to standard 3D APIs (OpenGL, DirectX, Vulkan, Metal), and an evolutionary near zero friction adoption by ecosystem (as opposed to revolutionary approach).

Adshir’s ray tracing engine, LocalRay®, runs without any accelerating hardware. Ray tracing functionality is executed by Compute and Graphics paths of GPU. Software not only ensures continuity with existing ecosystems, but it is a basis for cross-platform solutions and widens the ecosystem and the target market for ray tracing.

The distinctiveness of Adshir’s hybrid ray tracing technology stems from its proprietary dynamic acceleration structure and a coherent processing of secondary rays.

“In Adshir’s LocalRay the secondary rays are handled apriority in coherent beams. This improves the parallelism, performance, and cache usage. It is not limited in resolution/usage and no tricks.” (Jon Peddie Research, Sep. 23, 2020).

The amount of intersection tests has been reduced, the proprietary Dynamic Acceleration Structure made the repetitive reconstructions redundant and the ray coherence brought efficient parallelization of secondary rays. A real-time performance at low-power consumption has been achieved.

“Adshir has come up with a clever way to accelerate ray tracing — the first major algorithm development in a long time that not only speeds things up but uses less power”, VentureBeat, Dean Takahashi, August 12, 2018. The radically reduced power of LocalRay® stands at only 1% of that of RTX. With Adshir’s LocalRay® solution, battery-powered mobile devices can finally enjoy ray tracing for gaming, VR and AR. 

Real-Time Ray Tracing with Unity

The “Camaro” interactive real-time scene below including real-time skin animation and complex reflections was created for Smartphone using LocalRay® integration with Unity3D.

The scene consists of hundreds of thousands of polygons, skin-animated objects, 1 directional light and 2 spotlights. This ray tracing animated scene runs at 40 fps on a One Plus 8 phone, consuming about 3W. 

The ray tracing accuracy depends on the physical correctness of intersections tests. Finding the first intersection of a ray and a geometric surface primitive is the core operation of any ray tracing system.

Due to differences in intersection algorithms and different approaches, many of the commonly used intersection algorithms have intrinsic numerical problems that can result in visible artifacts, especially for ray tracing of free form surfaces.

In addition, already simple triangle meshes can report false ray intersections along the triangle boundaries. This is not the case with LocalRay® which was tested for ground truth versus the popular ray tracer V-ray.

All the intersection tests were found accurate. V-ray is used for visualizations and computer graphics in industries such as media, entertainment, film and video game production, industrial design, product design and architecture. 

The V-ray image was generated on the high-end GPU AMD RX5700 in 2 minutes, while the same image rendered with LocalRay® on a One Plus 8 Smartphone took only 25 msec. As demonstrated, both images are of the same photorealistic quality. 

Hybrid Approach

Nevertheless, the hybrid approach can vastly improve ray tracing performance because a complete image can be available in a demanded time. This can be done by adjusting the amount of ray traced objects, shadows, ambient occlusion, etc., when there is not enough time to finish calculations. The hybrid feature is valuable in video gaming, VR and AR where real time is crucial. Therefore the amount of ray tracing can be traded off for the performance. Having said that, the scene segments that are ray traced by LocalRay® are faithful to the ground truth.

Today, Adshir’s LocalRay® is the first and the only solution to deliver a hassle free, real-time software ray tracing solution for developers at the biggest and fastest growing market of mobile AR, VR and gaming. It is seamlessly integrated to the Unity game engine as a ray-traced material.

“Ray tracing is expected to spark a graphics revolution in video games. Pace at which technology will find its way to a mass gamer audience depends a lot on cost” (Financial Times, Jul. 27, 2019). Adshir with its low-cost mobile-adapted LocalRay® is set to democratize ray tracing for the mass gamer audience.

For additional information please view the Adshir video presentation from our RTRT Summit: REAL-TIME RAY TRACING FOR MOBILE DEVICES.