Tessellation ottimizzata con i futuri driver AMD Catalyst

AMD ha anticipato, con un comunicato stampa, quelle che saranno le principali novità che verranno introdotte con i driver Catalyst 11.1a hotfix, versione speciale dei driver Catalyst 11.1 previsti al debutto nel corso della prossima settimana.

E' interessante notare come AMD voglia anticipare alcune informazioni su driver prossimi al debutto, nello specifico riferendosi ad una release hotfix che si differenzierà da quella standard per una serie di incrementi prestazionali oltre che per una nuova serie di novità legate alle tecniche di tessellation.

Nello specifico AMD implementerà l'AMD Optimized Tessellation, una soluzione che attraverso il pannello Catalyst Control Center permette di avere un controllo diretto sulle tecniche di tessellation, forzando il massimo livello implementato dalla specifica applicazione in uso oppure scegliendo un livello di intervento inferiore.

AMD ha introdotto inoltre alcune ottimizzazioni al comportamento del filtro anisotropico; la finalità è quella di migliorare la qualità d'immagine fornita con l'impostazione "Quality" rispetto a quanto messo a disposizione sino ad ora, rendendola nella maggior parte degli scenari d'uso indistinguibile da quella "High Quality".

Di seguito alcune delle release note anticipate da AMD:

AMD Radeon HD 6900 and AMD Radeon HD 6800 Series:
• 3DMark Vantage improves ~7%
• 3DMark06 improves ~3%
• Call of Duty Black Ops improves ~20% at 4xMSAA and up to 35% at 8xMSAA
• Riddick Assault on Dark Athena SSAO performance improves ~20%
• Unigine Heaven OpenGL performance improves ~10% at moderate, 30% at normal and 100% at extreme tessellation levels

AMD Radeon HD 6800 Series:
• Aliens vs. Predators improves ~9% at 2xMSAA and up to 20% at 4xMSAA
• Batman Arkham Asylum improves ~4%
• Crysis Warhead improves ~2-4%
• Metro 2033 improves ~28% at 4xMSAA

AMD Radeon HD 6900 Series:
• Battleforge DirectX 11 performance improves as much as 6%

AMD Optimized Tessellation
The Catalyst Control Center includes an early prototype of some new tessellation controls. Our goal is to give users full control over the tessellation levels used in applications. The default selection “AMD Optimized” setting allows AMD, on a per application basis, to set the best level of tessellation. The intention is to help users get the maximum visual benefit of Tessellation, while minimizing the impact on performance. Currently no applications have been profiled, so the “AMD Optimized” setting will be non-operational until further notice.

The “Use Application Settings” option gives applications full control over the Tessellation level. Users can also manually set the maximum tessellation level used by applications with the slider control

The long term goal for the “AMD Optimized” setting is to use the Catalyst Application Profile mechanism to control the AMD recommended level of tessellation on a per application basis. AMD’s intention is to set the tessellation level such that we will not be reducing image quality in any way that would negatively impact the gaming experience."

We have changed the behavior of the texture filtering slider in our latest Catalyst Hotfix driver based on feedback, as detailed below.

• The HQ setting remains unchanged. This provides reference quality filtering from our hardware, meaning it does exactly what an application requests with no optimizations or tweaks of any kind.
• The Quality setting has now been improved to match the HQ setting in all respects except for one – it enables an optimization that limits trilinear anisotropic filtering to areas surrounding texture mipmap level transitions, while doing bilinear anisotropic filtering elsewhere. Sometimes referred to as “bilinear” filtering, it offers a way to improve filtering performance without visibly affecting image quality. It has no impact on texture sharpness or shimmering, and this can be verified by comparing it visually with the High Quality setting.

We continue to recommend the Quality setting as the best one to use for competitive testing for the following reasons:

• It should be visually indistinguishable from the High Quality setting for real textures (with the exception of special test patterns using colored mip levels)
• Visual quality should now be equal to the default setting used on HD 5800 series GPUs with Catalyst 10.9 and earlier drivers, or better when used on HD 6800/6900 series GPUs due to other hardware filtering improvements
• It matches the default texture filtering quality setting currently implemented on our competitor’s GPUs, which make use of the same trilinear filtering optimization
• The Performance setting has also been changed to address a few user comments regarding the sharpness of our default filtering settings causing shimmering in certain cases. It now provides a smoother filtering option that eliminates most shimmering while preserving the improved detail provided by anisotropic filtering. We accomplished this by applying a small LOD bias and tweaking some other characteristics of the filter in software. This setting also includes the trilinear optimization used in the Quality mode, since it offers improved performance with no discernable effect on sharpness or shimmering. Frame rates should be similar to those obtained with the quality setting.