World of Tanks enCore Ray Tracing Developers Q&A
4 min readWhy is ray tracing (RT) important for the video games industry?
Ray tracing allows for realistic lighting, reflections and shadows in video games, making the overall picture much more lifelike.
Unlike rasterization tech used to emulate light and shadow behaviour in games before, ray tracing generates them in real-time. The RT tech has been utilized for quite some time by the film and animation industries; it has only recently started to be employed in the games industry. The World of Tanks team decided to join those at the forefront of technology.
Ray tracing enhances the player’s experience and immersion by letting them see the protagonist of their game—in World of Tanks that means, naturally, the tank—in a more realistic light.
To fully tap into RT one needs a powerful gaming system, and it has been decided—for now—to use the tech only for tanks. Because in case we employ it for environment objects like trees, buildings, etc., the performance of the game may suffer.
The mainstream, lifestyle and gaming media need to have a very simple explanation of why this is so revolutionary. The fact they don’t need high-end graphics cards saves them a lot of money for example…
Previously, to make use of RT tech you had to have a special video card, one with cores providing hardware support for ray tracing calculations. Wargaming’s engineers together with our friends at Intel had the task of lowering the hardware requirements and making the RT tech more accessible—and they succeeded.
Technically speaking, the ray-traced shadows tech developed by Wargaming together with Intel uses the Intel Embree library (part of Intel One API) for fast multi-threaded BVH construction by the CPU; the GPU performs ray tracing with compute shaders. The advantage of this solution is that it does not require a graphics card with ray tracing support; DirectX 11 (or above) compatibility is enough. It should be noted that the first video card with DirectX 11 support was launched in 2009, a year before the release of World of Tanks. With each passing day, the installed base of systems with DX11-compatible video cards is expanding. Today there are few people among our players who need to update their system to see high-quality shadows in World of Tanks.
It also should be mentioned that once the World of Tanks Core graphics engine is updated, ray tracing will be switched off by default in the game client. The player will have to activate it manually in the Options menu. For a comfortable transition, we shall offer four grades of RT quality from zero to maximum so that users may adjust it depending on their system performance.
I remember Wargaming has collaborated with Intel before. What’s with this enCore generation? Maybe I am wrong, but there was already some enCore… So it’s a new generation… The difference between enCore that released in 2018 and this enCore. Maybe would be good to show to media those differences?
World of Tanks enCore RT is a demo app which allows assessing the effect that the RT tech has on the game, and also to check whether your system is capable of using it correctly. As we speak, every tanker can install the demo app on their PC and grade their system’s RT tech capabilities.
The first World of Tanks enCore was released some months before the graphical overhaul of Update 1.0. World of Tanks enCore RT is the second version that demonstrates the new capabilities of the Core engine that is being used in World of Tanks since Update 1.0.
One question is about this CPU/GPU usage. We claim that our ray tracing will be done mainly by CPU and you don’t need expensive graphic card supporting this tech GPU wise. So you can have it on some more basic DX11 graphics cards models. Are we the first to do it like this? Or there are some other companies/games who are also doing it this way?
It’s not done mainly by the CPU. It just uses multiple CPU threads to effectively rebuild a high-quality BVH structure for every frame. Ray tracing itself is done using compute shaders on the GPU. The high-quality BVH structure allows for better ray tracing performance on the GPU. Other games mainly use GPUs with hardware-accelerated ray tracing support. We are the first game to do it this way. As far as we know there is no released or announced the game with ray tracing support that works on graphics cards from different GPU vendors.
If it’s like stated above (we’re first to do ray tracing mainly though CPU and you need basic DX11 GPU) then how will it look in terms of quality? Will it be the same as RT coming from the GPU? Lower quality? Or maybe even higher? Will there be any differences or generally the same?
Ray tracing is a heavy technology performance-wise. Our achievement is that we have a similar (or, in some cases, smaller) performance drop compared to our competitors that implement ray-traced shadows with GPUs with hardware-accelerated ray tracing. We have achieved that because we don’t ray trace shadows from all objects, just shadows from tanks, and also due to extensive optimization. The quality is very close to what you get with hardware-accelerated ray tracing because we basically use the same algorithms.
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