EQAA Modes for AMD 6900 Series Graphics Cards

EQAA Modes for AMD 6900 Series Graphics Cards
AMD Developer Relations
[email protected]
Overview
Enhanced Quality Anti-Aliasing (EQAA) is a new anti-aliasing technology available from the AMD
HD 6900 series of graphics cards onwards. This new Anti-Aliasing (AA) technology offers
advanced smoothing of aliased edges without requiring additional video memory, and with a
minimal performance cost.
Coverage Sample Details
EQAA offers enhanced AA quality over standard Multi-Sample Anti-Aliasing (MSAA) modes by
adding more coverage samples per pixel but keeping the same number of color/depth/stencil
samples to achieve better AA quality than standard MSAA modes. Since it doesn’t require
additional color/depth/stencil samples, it consumes the same video memory as the equivalent
MSAA mode.
The coverage samples are used to test if a polygon is present at the location of the sample, and
these samples can be used as the weight value for calculating the final color of the pixel.
Because coverage samples can be gathered more easily than increasing color sample count,
EQAA can increase AA quality with quite a small performance overhead. EQAA is also
compatible with other existing AA techniques supported by AMD.
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EQAA Modes for AMD Graphics Cards
2x MSAA
No AA
4x MSAA
8x MSAA
= Pixel Boundary
= Color Sample
SampleleBo
= Coverage Sample
undary
2f4x EQAA
4f8x EQAA
8f16x EQAA
4 coverage samples
8 coverage samples
16 coverage samples
Figure1. MSAA and EQAA color/coverage sample patterns
How to Enable EQAA Modes in Direct3D®
Direct3D 9
In Direct3D 9, the programmers can use the combinations of multisample type and multisample
quality level to enable standard MSAA and new EQAA modes. To get the number of available
quality levels for a particular multisample type, the programmers can use the
IDirect3D9::CheckDeviceMultiSampleType() method of the Direct3D9 interface. Below is the
list of all combinations in Direct3D 9.
Multisample Type
Quality Level
AA Mode
Color Sample
Count
Depth/Stencil
Sample Count
Coverage Sample
Count
D3DMULTISAMPLE_NONE
D3DMULTISAMPLE_NONMASKABLE
0
0
1
2
3
4
5
6
7
0
1
2
3
4
0
1
2
0
1
2
No MSAA
2x MSAA
2f4x EQAA
4x MSAA
2f8x EQAA
4f8x EQAA
4f16x EQAA
8x MSAA
8f16x EQAA
2x MSAA
2x MSAA
2f4x EQAA
2f4x EQAA
2f8x EQAA
4x MSAA
4x MSAA
4f8x EQAA
8x MSAA
8x MSAA
8f16x EQAA
0
2
2
4
2
4
4
8
8
2
2
2
2
2
4
4
4
8
8
8
0
2
2
4
2
4
4
8
8
2
2
2
2
2
4
4
4
8
8
8
0
2
4
4
8
8
16
8
16
2
2
4
4
8
4
4
8
8
8
16
D3DMULTISAMPLE_2_SAMPLES
D3DMULTISAMPLE_4_SAMPLES
D3DMULTISAMPLE_8_SAMPLES
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EQAA Modes for AMD Graphics Cards
Direct3D 10/11
In Direct3D 10/11, the programmers can use the combinations of multisample count and
multisample quality level to enable variable standard MSAA and new EQAA modes. To get the
number of available quality levels for particular multisample count, the programmers can use
ID3D11Device::CheckMultisampleQualityLevels() method of Direct3D10/11 device interface.
Below is the list of all combinations in Direct3D 10/11.
Multisamples Count
Quality Level
AA Mode
Color Sample Count
0
2
0
0~3
4
0~7
8 ~ 15
16
0 ~ 15
16
No MSAA
2x MSAA
2f4x EQAA
4x MSAA
4f8x EQAA
4f16x EQAA
8x MSAA
8f16x EQAA
0
2
2
4
4
4
8
8
4
8
Depth/Stencil
Sample Count
0
2
2
4
4
4
8
8
Coverage Sample
Count
0
2
4
4
8
16
8
16
Remark: In Direct3D 10.1/11 programmers are able to access individual sample data via the Load()
shader instruction. However it is not possible to access the additional coverage samples of EQAA modes.
For example when selecting 4f8x EQAA mode, only the first 4 samples (sample index 0 to 3) can be
accessed from the shader and the remaining 4 samples (sample index 4 to 7) cannot be retrieved.
This limitation may impact the ability to leverage EQAA for deferred or semi-deferred rendering
techniques.
How to enable EQAA Modes in OpenGL®
Currently AMD does not provide a specific extension to create an EQAA-enabled render buffer.
However end-users can still enable EQAA by using AMD Catalyst Control Center to override the
AA settings of application.
Please send your feedback to: [email protected]
Advanced Micro Devices
One AMD Place
P.O. Box 3453
Sunnyvale, CA 94088-3453
www.amd.com
http://www.amd.com/developer
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