ethomaz on 30 April 2014
You will need to read.
http://www.eurogamer.net/articles/digitalfoundry-2014-trials-fusion-tech-interview
But in resume...
- Development started in 2012... they are excited with works with next-gen and multiplatform (Trials was exclusive to 360 last gen).
- The locked 60fps goal impacts both our content production and our programming practices, as every single frame needs to finish in a tight 16.6ms budget.
- We recently noticed that the console launch version and the first day update of Trials Fusion had a serious bug regarding data streaming and frame-rate optimisations.
- Next patch: Finally the players can enjoy the locked 60fps also on Xbox One, and much reduced texture popping on PS4.
- In Trials Fusion we moved to a physically-based HDR rendering pipeline. This has been a common trend among AAA next-gen console titles.
- On the Xbox 360 we use our own custom version of FXAA.
- On next-generation consoles we also use FXAA at launch, because we had to prioritise resolution and frame-rate over antialiasing quality. FXAA looks surprisingly good on 1080p at a locked 60fps.
- Plans to provide better AA in PS4/Xbone in future patch.
- We had our own unique way of maximising the ESRAM usage. We used an Excel sheet to track the lifetime of each resource during a frame. We split the frame into four passes (shadows, G-buffer rendering, lighting and post processing), and then tried to get as many as possible live resources simultaneously to ESRAM in each pass, while trying to keep as many resources in ESRAM that were needed later. This was a really successful strategy and allowed us to utilise over 95 per cent of ESRAM space in three out of our four passes. We have also planned to automate this process in the future using an algorithm similar to those used by compilers to do register allocation and spilling.
- Optimising the render target size to fit it better to the fast ESRAM scratchpad reduces bandwidth cost and that boost performance on PS4 and PC GPUs as well.
- At the end, we got very close to platform parity between the next-generation consoles. Both consoles are running the game at locked 60fps, with identical shader and effect quality and with identical content (textures, models and levels). Rendering resolution is the only difference between the platforms. PS4 renders at slightly higher 1080p resolution than Xbox One (900p).
- For Trials Fusion, more GPU performance was the preferred choice over more CPU performance, as it is a cross-generation game.
- We had to run the same code base on Xbox 360 and on next-generation consoles. Fortunately Xbox 360 has six hardware threads, so each thread could be easily mapped to a separate physical CPU core on next-gen consoles.
- Generally the new CPUs were running our old PPC-optimised code very well. We only had to rewrite a few VMX128 optimised loops using AVX instructions to allow higher number of simultaneous active animations and physics objects. In the end we decided to double the complexity limitations of our in-game editor compared to the Xbox 360 version, allowing the users to build larger and more dynamic tracks for the next-generation consoles.
- I love GPU compute! You can do many things more efficiently using compute than using a pixel shader. Unfortunately for Trials Fusion we couldn't use that much GPU compute.
- Currently OpenGL is the most feature-rich graphics API on PC. OpenGL 4.4 exposes most of the new hardware features of AMD GCN and Nvidia Kepler GPUs that are not yet exposed in DirectX 11. Features such as indirect multi draw call, bindless resources and sparse textures are very important for us in the future.
- DirectX 12 is expected to expose pretty much the same GPU features as OpenGL 4.4 does, while reducing the draw call overhead near to Mantle level. Add solid driver support and cross-vendor GPU support (Nvidia, AMD and Intel are all backing DirectX 12) and the other options are not looking that interesting anymore.
