Zatrais
2003-03-13, 02:10 PM
I'm sure some of you forum and IRC regulars know that i'm addicted to AA, FA and ATI's texture filtering... Figured i'd make a post that shows the differences between the 2 makers when it comes to imagequality.
Both the GF4 and the Radeon 9500+ series pump out enough FPS, hell in most cases the FPS you get is overkill so whats next to look at... Imagequality.
So enough delays, on whit the pictures.
http://www.3dvelocity.com/reviews/gffx5800u/screenshots/iqcombatfsthumb.jpg
Note, performance setting is the worst image quality for ATI cards. That shot shows the difference in rendering... No AF in that shot.
Now, on to the AA..
http://www.hardocp.com/images/articles/1030137851qW5Z873PPk_2_9_l.jpg
http://www.hardocp.com/images/articles/1030137851qW5Z873PPk_2_4_l.jpg
The choice is yours, go whit the good ol nVidia or go whit ATI? nVidia does have a better track record whit drivers, but will ATI's CATALYST series win over the buyers? *shrug* not my call, just figured i would show you the differences.
Dictionary:
AA - Antialising
In short: removes jagged edges.
-Explaining this completely would mean explaining the whole mathematical sampling theory. It boils down to this. To recover a signal , or image, you need a minimum of samples to be able to give a realistic representation of the image. The problems start with texture maps being either too close or too far away from the viewpoint. If the polygon is far away you only have a limited number of points to show the texture map, so logically you have to drop a lot of the real pixels of your texture map. This creates some sort of interlace effect : one line is shown and one is not. This can result in weird patterns (moir� patterns) appearing, and makes the texture map look completely different from the real one. A similar problem if the polygon is close to you. You need more info than there is resulting in the generation of random noise (meaningless values). Most of the time the last problem is solved by MIP-Mapping while the other is solved by the anti-aliasing. Another point where anti-aliasing is used is with straight lines, usually abrupt changes in color from pixel to pixel, the border of a polygon for example. If you draw a straight line (under an angle) using a paint program and you zoom in, you will discover that the line looks like a stairway. To remove this and make the line look like a line points in different colors are added to the side of the line to make it look more like a real line. Most of the time it is this kind of Anti-Aliasing they are talking about. All Next Generation hardware support some form of AntiAliasing but only Full Scene AntiAliasing as used by PowerVR Second Generation does not need the CPU for this. The Edge Anti Aliasing techniques used by Voodoo2 and others needs the CPU to prepare the data (sorting, etc...). Results of AntiAliasing are amazing.
AF - Anisotropic filtering:
In short: clear, not smeared textures on all surfaces and angels.
Conventional texture filtering techniques do not compensate for anisotropy--the elongation of the screen pixel when it is mapped into texture space. This results in either blurring or aliasing, depending on the choice of texture level-of-detail. To achieve sharp textures, a card can use anisotropic filtering, a process that involves an elliptical kernel whose shape and orientation depends on the projection of the destination pixel onto the texture map
Note: all pictures and rights are the property of their owners. The explenations are taken (i think those are good and i'm to lazy to write my own hehe) from www.beyond3d.com a site i suggest if your into the more technical sides of things.
Both the GF4 and the Radeon 9500+ series pump out enough FPS, hell in most cases the FPS you get is overkill so whats next to look at... Imagequality.
So enough delays, on whit the pictures.
http://www.3dvelocity.com/reviews/gffx5800u/screenshots/iqcombatfsthumb.jpg
Note, performance setting is the worst image quality for ATI cards. That shot shows the difference in rendering... No AF in that shot.
Now, on to the AA..
http://www.hardocp.com/images/articles/1030137851qW5Z873PPk_2_9_l.jpg
http://www.hardocp.com/images/articles/1030137851qW5Z873PPk_2_4_l.jpg
The choice is yours, go whit the good ol nVidia or go whit ATI? nVidia does have a better track record whit drivers, but will ATI's CATALYST series win over the buyers? *shrug* not my call, just figured i would show you the differences.
Dictionary:
AA - Antialising
In short: removes jagged edges.
-Explaining this completely would mean explaining the whole mathematical sampling theory. It boils down to this. To recover a signal , or image, you need a minimum of samples to be able to give a realistic representation of the image. The problems start with texture maps being either too close or too far away from the viewpoint. If the polygon is far away you only have a limited number of points to show the texture map, so logically you have to drop a lot of the real pixels of your texture map. This creates some sort of interlace effect : one line is shown and one is not. This can result in weird patterns (moir� patterns) appearing, and makes the texture map look completely different from the real one. A similar problem if the polygon is close to you. You need more info than there is resulting in the generation of random noise (meaningless values). Most of the time the last problem is solved by MIP-Mapping while the other is solved by the anti-aliasing. Another point where anti-aliasing is used is with straight lines, usually abrupt changes in color from pixel to pixel, the border of a polygon for example. If you draw a straight line (under an angle) using a paint program and you zoom in, you will discover that the line looks like a stairway. To remove this and make the line look like a line points in different colors are added to the side of the line to make it look more like a real line. Most of the time it is this kind of Anti-Aliasing they are talking about. All Next Generation hardware support some form of AntiAliasing but only Full Scene AntiAliasing as used by PowerVR Second Generation does not need the CPU for this. The Edge Anti Aliasing techniques used by Voodoo2 and others needs the CPU to prepare the data (sorting, etc...). Results of AntiAliasing are amazing.
AF - Anisotropic filtering:
In short: clear, not smeared textures on all surfaces and angels.
Conventional texture filtering techniques do not compensate for anisotropy--the elongation of the screen pixel when it is mapped into texture space. This results in either blurring or aliasing, depending on the choice of texture level-of-detail. To achieve sharp textures, a card can use anisotropic filtering, a process that involves an elliptical kernel whose shape and orientation depends on the projection of the destination pixel onto the texture map
Note: all pictures and rights are the property of their owners. The explenations are taken (i think those are good and i'm to lazy to write my own hehe) from www.beyond3d.com a site i suggest if your into the more technical sides of things.