Mai intai si intai, ce este Morphological Antialiasing – MLAA? MLAA este un filtru de postprocesare menit sa reduca “dintii de firiz / zgrimturile” de pe o imagine. Algoritmul prin care este posibil acest lucru poate fi implementat in motorul grafic sau la nivel de driver.
In short, MLAA is a shape-based anti-aliasing method that uses post processing filters to reduce aliasing. Like the SSAO, MLAA can be hand-coded in a 3D app or added in graphics drivers.
Intel are o documentatie foarte bine pusa la punct care explica in detaliu aspectele tehnice al acestui algoritm:
http://visual-computing.intel-research.net/publications/papers/2009/mlaa/mlaa.pdf
MLAA can be used for any image processing task and does not use any data besides color values. It is very simple and does not require any modifications to the rendering pipeline.
It does not need casting any additional rays.
The algorithm is embarrassingly parallel and can be executed concurrently with rendering threads (using double buffering), allowing for better processor utilization.
The algorithm achieves reasonable performance, in many cases without any noticeable impact.
The quality is comparable with supersampling. MLAA has very different approximation characteristics, achieving better results in situations in which uniform sampling suffers from significant errors and undesired frequencies.
Puteti dezbate acest subiect si pe forum: ATI/AMD’s new Morphological Anti-aliasing
Odata cu versiunea 10.10 WHQL a driverului video, placile grafice AMD Radeon 6780 si 6850 beneficiaza la randul lor de acest nou tip de antialiasing, implementat la nivel de driver. Poate pentru PC este o premiera acest lucru, insa MLAA a fost folosit pentru prima data, cu un real succces, in fenomenul numit God of War 3, joc lansat exclusiv pe consola celor de la Sony.
Last week, AMD has released its own GPU-based MLAA implementation for PC and other developers are working on GPU solutions for Xbox 360. MLAA is going cross-platform.
tomshardware.com are un articol complet care trateaza implementarea noului algoritm pe seria 6000 de la AMD. Link: Morphological Anti-Aliasing
Morphological anti-aliasing (AA) is an all-new option for the Radeon HD 6000-series cards. It presents a different approach to the aliasing problem in that it needs no insight into the makeup of the scene’s geometry; morphological AA is a post-process filtering technique, accelerated with DirectCompute and compatible with any application from DirectX 9 to 11 (in theory). After a frame is rendered, it is passed through the morphological AA shader that looks for high-contrast edges and patterns consistent with aliasing. It then blends the colors of adjacent pixels to approximate a smooth transition along a line instead of aliased steps. This means that the smoothing effect isn’t limited to the edges of geometry or alpha textures like CFAA; it applies to all of the pixels in the scene.
Conceptually, this method promises results similar to super-sampling, but with performance comparable to edge-detect AA. AMD suggests that some applications will look better than others, and that the technique is not ideal for all scenes and games. So, we tried it ourselves to see what the actual result looks like.
AMD se foloseste de tehnologia Direct Compute din DirectX pentru a accelera hardware MLAA. MLAA este independent de celelalte tipuri de antialiasing si mai mult decat atat, poate fi folosit in combinatie cu ele. Desi nu toate jocurile din acest moment sunt compatibile cu MLAA, unde se poate active, rezultatele sunt impresionante si mai mult decat atat, hit-ul de performanta este extrem de mic.

Desi nu este o tehnologie perfecta, rezultatele obtinute sunt deosebite.

Trebuie notat ca Morphological AA este un efect de postprocesare, asa ca nu poate fi capturat cu software de captura gen FRAPS. Pe moment, singurul inconvenient major al folosirii MLAA este rezolutia mica [720p sau mai jos] combinata cu text. Datorita rezolutiei mici si faptului ca MLAA este un efect de postprocesare pixel per pixel, la rezolutie mica poate aparea un efect deranjant de blur chiar si in locurile in care ati dori ca imaginea sa ramana sharp [de obicei este vorba de text].
Pentru God of War pe PS3, Sony a implementat MLAA folosind 5 sateliti ai CELL-ului, degrevand astfel in totalitate cip-ul grafic: http://www.eurogamer.net/articles/digitalfoundry-mlaa-360-pc-article
AMD’s solution has much in common with Sony’s, but is fundamentally different in many ways. The fact that the God of War III MLAA operates on SPU has some very specific advantages – the Cell’s satellite processors are far more flexible in terms of how they can be programmed, leading some to believe that GPU implementations will struggle to match the quality level.
Implementarea AMD se foloseste de GPU pentru a randa MLAA iar acest efect de postprocesare se aplica intregii planse, incluzand HUD-ul si orice text existent pe imagine. Din acest motiv, cum am explicat mai sus, poat aparea anomalii de randare / artefacte pe text. Algoritmul de MLAA pur si simplu nu poate face diferenta intre o margine si un text sau elementele din HUD, aplicand antialiasing-ul pe intreaga imagine.
More obvious to the end user, AMD’s approach is a post-process filter that works through the entire completed frame, including the HUD and any on-screen text. This results in exactly the same kind of artifacting on text as seen with The Saboteur on PS3. As the MLAA algorithm works on the whole screen, it simply doesn’t know the difference between a genuine edge and text, resulting in a noticeable impact to quality, along with occasional dot-crawl on HUD elements.
Desi aceste artefacte se reduc in cazul folosirii unei rezolutii inalte [1080p sau mai mult], actuala implementare a algoritmului nu permite eliminarea totala a anomaliilor de randare pe text. Implementarea SONY aplica algoritmul pe intreaga plansa dar inaintea desenarii pe imagine a oricarui text sau element de pe HUD, producand rezultate superioare implementarii AMD.

AMD’s MLAA is best deployed at higher resolutions, such as 1080p in order to minimise the artifacts inherent in this technique. That Sony were able to minimise these issues and make it 720p-friendly is an exceptional achievement
Daca nVidia ar implementa la randul ei MLAA si ar programa driverul de asa natura incat sa se foloseasca de CUDA Cores, probabil hit-ul de performanta ar fi de cateva procente. Cat timp MLAA este calculat folosind DirectCompute iar DirectCompute este accelerat hadware pe cipurile nVidia prin CUDA, implementarea acestui algoritm de antialiasing pe placile grafice cu GPU-uri FERMI ar fi un real succes. Nu ramane decat sa asteptam raspunsul nVidia.


































