Grand lecteur de forum plus que posteur fou j'ai trouve ceci sur un forum, apparement un developpeur ayant participé a la WWDC nous donne quelques precisions sans briser sa NDA
Well, I'll tell you about the one that was briefly shown in the keynote (and explained in great detail in one the Quartz sessions).
But, before I describe the scene, I want to make it very clear what Quartz Extreme (QE) is. QE is not about graphics acceleration. It's more accurate to think of graphics acceleration as a side effect of what QE does. Quartz Extreme is literally an implementation of the Quartz Compositor in OpenGL. And, not only that, but all I/O operations are carefully coded to use DMA only (versus programmed I/O), freeing the processor from both compositing the pixels, and pushing them out to the destination device (ie: the "side effect").
And to further clarify, the term Quartz refers to two seperate elements. One is Quartz 2D. This is the 2D API that is used to draw 2D elements. The other is the Quartz Compositor. This piece is responsible for integrating and compositing the 2D, 3D, and media elements generated by Quartz 2D, OpenGL, and QuickTime. Quartz Extreme deals with the Quartz Compositor, not Quartz 2D. So, to reiterate, Quartz Extreme does not accelerate Quartz 2D.
(the popular view of graphics in Mac OS X)
(what's actually there)
So, on to the demo in the keynote.
During the keynote, the primary demo used to show off the power of the Quartz Compositor involved the compositing of several layers of raw motion pictures from a movie, to create a scene (sorry, can't remember which movie it's from). Now, this doesn't sound too terribly complex, does it? You're probably thinking, "Final Cut Pro can do that now with its real-time effects!" Well, here's what made this hard (read: impossible) to do before, in real-time, without additional add-on cards.
The scene consisted of 5 layers:
-one background plate with the "sky" and background scenery
-one back ground plate of a train station, with green screen where the sky and environment should show through
-two layers of actors, on stages, in front of a green screen
-one layer of a model train, on a stage, in front of a green screen
During the keynote, these five layers were composited, with garbage mattes, chroma keys and colour correction, all in real time! It doesn't sound as impressive with me describing it here, but try this in After Effects and it would take hours to render! Remember: real-time!
However, during one of the Quartz session I attended, this demo was went over in greater detail, with even more complexity added to the scene. So, what was added?
-the angle on the two plates of actors, and the train station were off. The actors were skewed, rotated, and scaled to match, in real time.
-three floating, rotating, transparent 3D objects were added
-realtime scrolling credits were added to the scene
You had to have seen it, to fully understand how incredible this was.
As for the DVD demo movie that was posted earlier today, a similar demo was shown at WWDC. However, it involved a DVD movie, 20 transparent terminal windows (which is actually 40 transparent layers in the Quartz Compositor), and the same 3 floating, rotating, transparent 3D objects floating above all that. For comparison, it's not even possible to composite the volume indicator in front of a DVD in 10.1.4!
I wish I could tell you guys everything about QE. But, if I did that, I probably wouldn't be able to get stuff from Apple anymore.
But, the point is: do not think of Quartz Extreme as graphics acceleration, think of Quartz Extreme as a graphics compositor on steroids^(squared). As I said, the "graphics acceleration" is more of a side effect, despite the exponential increase in complexity that Quartz Extreme allows. Another note: all the new OpenGL extensions required to make the QE version of the Quartz Compositor are also available to developers. So, it's really up to the developers to come up with interesting (eg: 40 terminals over a DVD) and useful (eg: the film compositing demo) ways to use this new power.
[23 mai 2002 : message édité par mtra]
rajout du contexte
[23 mai 2002 : message édité par mtra]
Well, I'll tell you about the one that was briefly shown in the keynote (and explained in great detail in one the Quartz sessions).
But, before I describe the scene, I want to make it very clear what Quartz Extreme (QE) is. QE is not about graphics acceleration. It's more accurate to think of graphics acceleration as a side effect of what QE does. Quartz Extreme is literally an implementation of the Quartz Compositor in OpenGL. And, not only that, but all I/O operations are carefully coded to use DMA only (versus programmed I/O), freeing the processor from both compositing the pixels, and pushing them out to the destination device (ie: the "side effect").
And to further clarify, the term Quartz refers to two seperate elements. One is Quartz 2D. This is the 2D API that is used to draw 2D elements. The other is the Quartz Compositor. This piece is responsible for integrating and compositing the 2D, 3D, and media elements generated by Quartz 2D, OpenGL, and QuickTime. Quartz Extreme deals with the Quartz Compositor, not Quartz 2D. So, to reiterate, Quartz Extreme does not accelerate Quartz 2D.
(the popular view of graphics in Mac OS X)
(what's actually there)
So, on to the demo in the keynote.
During the keynote, the primary demo used to show off the power of the Quartz Compositor involved the compositing of several layers of raw motion pictures from a movie, to create a scene (sorry, can't remember which movie it's from). Now, this doesn't sound too terribly complex, does it? You're probably thinking, "Final Cut Pro can do that now with its real-time effects!" Well, here's what made this hard (read: impossible) to do before, in real-time, without additional add-on cards.
The scene consisted of 5 layers:
-one background plate with the "sky" and background scenery
-one back ground plate of a train station, with green screen where the sky and environment should show through
-two layers of actors, on stages, in front of a green screen
-one layer of a model train, on a stage, in front of a green screen
During the keynote, these five layers were composited, with garbage mattes, chroma keys and colour correction, all in real time! It doesn't sound as impressive with me describing it here, but try this in After Effects and it would take hours to render! Remember: real-time!
However, during one of the Quartz session I attended, this demo was went over in greater detail, with even more complexity added to the scene. So, what was added?
-the angle on the two plates of actors, and the train station were off. The actors were skewed, rotated, and scaled to match, in real time.
-three floating, rotating, transparent 3D objects were added
-realtime scrolling credits were added to the scene
You had to have seen it, to fully understand how incredible this was.
As for the DVD demo movie that was posted earlier today, a similar demo was shown at WWDC. However, it involved a DVD movie, 20 transparent terminal windows (which is actually 40 transparent layers in the Quartz Compositor), and the same 3 floating, rotating, transparent 3D objects floating above all that. For comparison, it's not even possible to composite the volume indicator in front of a DVD in 10.1.4!
I wish I could tell you guys everything about QE. But, if I did that, I probably wouldn't be able to get stuff from Apple anymore.
But, the point is: do not think of Quartz Extreme as graphics acceleration, think of Quartz Extreme as a graphics compositor on steroids^(squared). As I said, the "graphics acceleration" is more of a side effect, despite the exponential increase in complexity that Quartz Extreme allows. Another note: all the new OpenGL extensions required to make the QE version of the Quartz Compositor are also available to developers. So, it's really up to the developers to come up with interesting (eg: 40 terminals over a DVD) and useful (eg: the film compositing demo) ways to use this new power.
[23 mai 2002 : message édité par mtra]
rajout du contexte
[23 mai 2002 : message édité par mtra]
