Feature levels in Direct3D

Feature levels in Direct3D define strict sets of features required by certain versions of the Direct3D API and runtime, as well as additional optional feature levels available within the same API version.

Overview

Feature levels encapsulate hardware-specific capabilities that exist on top of common mandatory requirements and features in a particular version of the API. The levels are grouped in strict supersets of each other, so each higher level includes all features required on every lower level.

Some feature levels include previously optional hardware features which are promoted to a mandatory status with new revisions of the API to better expose newer hardware. More advanced features such as new shader models and rendering stages are only exposed on up-level hardware,[1][2] however the hardware is not required to support all of these feature levels[3] and the Direct3D runtime will make the necessary translations.

Feature levels allow developers to unify the rendering pipeline and use a single version of the API on both newer and older hardware, taking advantage of performance and usability improvements in the newer runtime.[4]

Separate capabilities exist to indicate support for specific texture operations and resource formats; these are usually specified per each texture format using a combination of capability flags, but some of these optional features are promoted to mandatory on upper feature levels.[5]

Direct3D 10

Direct3D 10 introduced a fixed set of mandatory requirements for the graphics hardware. Before Direct3D 10, new versions of the API introduced support for new hardware capabilities, however these capabilities were optional and had to be queried with "capability bits" or "caps".

Direct3D 10.1 API was the first to use a concept of "feature levels" [1][3][6] to support both Direct3D 10.0 and 10.1 hardware.[3][7][8]

Direct3D 11

In Direct3D 11, the concept of feature levels has been further expanded to run on most downlevel hardware including Direct3D 9 cards with WDDM drivers.

There are seven feature levels provided by D3D_FEATURE_LEVEL structure; levels 9_1, 9_2 and 9_3 (collectively known as Direct3D 10 Level 9) re-encapsulate various features of popular Direct3D 9 cards conforming to Shader Model 2.0, while levels 10_0, 10_1, 11_0 and 11_1 refer to respective versions of the Direct3D API.[1] "10 Level 9" feature levels contain a subset of the Direct3D 10/11 API[9] and require shaders to be written in HLSL conforming to Shader Model 4.0 4_0_LEVEL_9_x compiler profiles, and not in the actual "shader assembly" language[10] of Shader Model 1.1/2.0; SM 3.0 (vs_3_0/ps_3_0) has been omitted deliberately in Direct3D 10 Level 9.[3]

Since Direct3D 11.1 for Windows 8, some mandatory features introduced for level 11_1 are available as optional on levels 10_0, 10_1 and 11_0 - these features can be checked individually via CheckFeatureSupport function[11] however feature level 11_1 and optional features are not available in Direct3D 11.1 for Windows 7 platform update[12] because it does not support WDDM 1.2.[13]

Direct3D 11.2 for Windows 8.1 adds optional mappable buffers and optional tiled resources for levels 11_0 and 11_1; these features require WDDM 1.3 drivers.[14]

Direct3D 11.3 for Windows 10 requires WDDM 2.0 drivers; it adds more optional features and levels 12_0 and 12_1 from Direct3D 12.

Direct3D 10 and 11 feature levels
Required features Optional features GPUs supporting as a maximum feature level
Feature level Direct3D runtime Driver model Features Direct3D runtime Driver model Features
9_1 11.0 WDDM 1.0 Shader Model 2.0 (vs_2_0/ps_2_0), 2K textures, volume textures, event queries, BC1-3 (aka DXTn), a few other specific capabilities. N/A Nvidia GeForce FX; Intel GMA 950/3000 (945G/965G chipset); Tegra 3, Tegra 4
9_2 Occlusion queries, floating-point formats (no blending), extended caps, all 9_1 features. ATI Radeon 9500
9_3 vs_2_a/ps_2_x with instancing and additional shader caps, 4K textures, multiple render targets (4 MRTs), floating-point blending (limited), all 9_2 features. ATI Radeon X1300; Nvidia GeForce 6600; Adreno 220/300 series; Mali-T 6xx/720/820/830;[15] Matrox M-series; Vivante GC2000 series onwards[16]
10_0 10.0 Shader Model 4.0, geometry shader, stream out, alpha-to-coverage, 8K textures, MSAA textures, 2-sided stencil, general render target views, texture arrays, BC4/BC5, full floating-point format support, all 9_3 features. ATI Radeon HD2000 series; Nvidia GeForce 8/9/GTX 200 series; Intel GMA X3100-X4500 (GM965/G35/G45 chipset), Intel HD Graphics (Arrandale/Clarkdale CPUs)
10_1 10.1 Shader Model 4.1, cubemap arrays, extended MSAA, all 10_0 features. ATI Radeon HD 3000/4000 series; Nvidia GT 205-240/GT 300 series;

Intel HD Graphics 3000/2000 (Sandy Bridge)

11_0 11.0 WDDM 1.1 Shader Model 5.0, hull & domain shaders, DirectCompute (CS 5.0), 16K textures, BC6H/BC7, extended pixel formats, all 10_1 features. 11.1 WDDM 1.2[11] 10_x: DirectCompute (CS 4.0/CS 4.1), extended pixel formats, logical blend operations.
11_0: UAV only rendering with force sample count, constant buffer offsetting and partial updates, double precision (64-bit) floating point operations, minimum floating point precision (10 or 16 bit).		 AMD Radeon HD 5000/6000/7300-7600/8300-8400, R5 210-235 series (Terascale 2), HD 6900 (Terascale 3);

Nvidia GeForce GTX 400/500;
Intel HD Graphics 4000/2500 (Ivy Bridge)

11.3 WDDM 2.0 Shader Model 5.1 [17] 11.2 WDDM 1.3 11_x: Tiled resources (two tiers), min/max filtering Nvidia GeForce GTX 600/700/Titan series (Kepler), GTX 745/750 series (Maxwell, 1st gen)
11_1 11.1 WDDM 1.2 Logical blend operations, target-independent rasterization, UAVs at every pipeline stage with increased slot count, UAV only rendering with force sample count, constant buffer offsetting and partial updates, all 11_0 features. 11.3 WDDM 2.0 11_x/12_x: Conservative rasterization (three tiers),[18] tiled resources (three tiers), stencil reference value from Pixel Shader, rasterizer ordered views, typed UAV loads for additional formats, UMA/hUMA support[19] Mali-T 760/860/880; Adreno 400 series;

AMD HD 7700-7900/8500-8900, Rx 240/250/265/270/280, Rx 330/340/350/370 series (GCN1);
Intel HD Graphics 4200-5200 (7.5 gen, Haswell), 5300-6300 (8 gen, Broadwell)

12_0 11.3 WDDM 2.0 Tiled Resources Tier 2 (Texture2D), Typed UAV Loads (additional formats). AMD HD 7790/8770, Rx 260/290, Rx 360/390 series, Xbox One (GCN2), R9 285/380, Fury/Nano series (GCN3), 400 series (GCN4)
12_1 Conservative Rasterization Tier 1, Rasterizer Ordered Views. Nvidia GeForce 900/Titan series (Maxwell, 2nd gen);[20][21][22][23][24] GeForce 10 series (Pascal)

Intel HD Graphics 510-580 (9 gen, Skylake),[25] 605-620 (9.5 gen, Kaby Lake)

Feature level Direct3D runtime Driver model Features Direct3D runtime Driver model Features GPUs supporting as a maximum feature level
Required features Optional features

Direct3D 12

Direct3D 12 requires graphics hardware conforming to feature levels 11_0 and 11_1 which support virtual memory address translations.[26][27]

There are two new feature levels, 12_0 and 12_1, which include some features that are optional on levels 11_0 and 11_1.[28] Due to the restructuring of the API, some previously optional features are realigned as baseline on levels 11_0 and 11_1.

Direct3D 12 from Windows 10 anniversary update includes Shader Model 6.0 [29] which requires WDDM 2.1 drivers.

Direct3D 12 feature levels
Level Driver model Required features Optional features GPUs supporting as a maximum feature level
11_0 WDDM 2.0 All mandatory 11_0 features from Direct3D 11, Shader Model 5.1, Resource binding Tier 1.

UAVs at every pipeline stage, UAV only rendering with force sample count, constant buffer offsetting and partial updates.

 Resource binding (three tiers), tiled resources (three tiers), conservative rasterization (three tiers), stencil reference value from Pixel Shader, rasterizer ordered views, typed UAV loads for additional formats, UMA/hUMA support.

Logical blend operations, double precision (64-bit) floating point operations, minimum floating point precision (10 or 16 bit).

Shader Model 6.0

 Nvidia GeForce GTX 600/700/Titan series (Kepler), GTX 745/750 series (Maxwell, 1st gen)
11_1 Logical blend operations, target-independent rasterization, increased UAV slot count. AMD HD 7700-7900/8500-8900, Rx 240/250/265/270/280, Rx 330/340/350/370 series (GCN1);

Intel HD Graphics 4200-5200 (7.5 gen, Haswell), 5300-6300 (8 gen, Broadwell)

12_0 WDDM 2.0 Resource Binding Tier 2, Tiled Resources Tier 2 (Texture2D), Typed UAV Loads (additional formats) AMD HD 7790/8770, Rx 260/290, Rx 360/390 series, Xbox One (GCN2), R9 285/380/Fury/Nano series (GCN3), 400 series (GCN4)
WDDM 2.1 Shader Model 6.0
12_1 Nvidia GeForce 900/Titan series (Maxwell, 2nd gen);[20][21][22][23][24] GeForce 10 series (Pascal)

Intel HD Graphics 510-580 (9 gen, Skylake),[25] 605-620 (9.5 gen, Kaby Lake)

WDDM 2.0 Conservative Rasterization Tier 1, Rasterizer Ordered Views.

Direct3D introduces a revamped resource binding model, allowing explicit control of memory. Abstract resource "view" objects[30] which allowed random read/write access are now represented by resource descriptors, which are allocated using memory heaps and tables.[31] This model is supported on majority of existing desktop GPU architectures and requires WDDM 2.0 drivers. Supported hardware is divided into three Resource Binding tiers, which define maximum numbers of descriptors that can be used for CBV (constant buffer view), SRV (shader resource view) and UAV (unordered access view); CBVs and SRVs per pipeline stage; UAVs for all pipeline stages; samplers per stage; and the number of SRV descriptor tables. Tier 3 hardware such as AMD GCN and, Intel Skylake has no limitations, allowing fully bindless resources only limited by the size of the descriptor heap, while Tier 1 (Intel Haswell/Broadwell) and Tier 2 (Nvidia Kepler/Maxwell) hardware impose some limits on the number of descriptors ("views") that can be used simultaneously. Additionally, buffers and textures can mixed together in the same resource heap only on hardware supporting Resource Heap Tier 2, while Tier 1 hardware requires separate memory heaps for buffers, textures, and render-target and depth stencil surfaces. Resource binding tier 1 and resource heap tier 1 are required for all supporting hardware.

Resource binding tiers
Resource limits Tier 1 Tier 2 Tier 3
Descriptors in CBV/SRV/UAV heap 1M >1M
CBVs per shader stage14 full heap
SRVs per shader stage128 full heap
UAVs across all stages8 64full heap
64†
Samplers per shader stage 16full heap
Feature level required 11_0 11_1
† 64 slots on feature level 11_1 hardware

Some of the optional features such as tiled resources and conservative rasterization have "tiers" which define the set of supported capabilities.

Tiled resources tiers
Capability Tier 1 Tier 2 Tier 3
Tiled BufferYes
Tiled Texture2D Yes
Sample with LOD clampNo Yes
Sample with Feedback No Yes
NULL tile read undefined zero
NULL tile writeundefined discarded
Tiled Texture3D No Yes

Conservative rasterization tiers
Capability Tier 1 Tier 2 Tier 3
Required uncertainty region 1/2 px 1/256 px
Post-snap degenerate triangles No Not culled
Inner input coverage No Yes

Most features are optional for all feature levels, but some of these features are promoted to required on higher feature levels.

Direct3D 12 optional feature support matrix by vendor/GPU series
Microsoft AMD Radeon Nvidia GeForce Intel HD Graphics
WARP12 GCN 1 GCN 2 GCN 3 / GCN 4 Kepler Maxwell
(1st gen) 		Maxwell
(2nd gen) 		Pascal Haswell
(7.5 gen) 		Broadwell
(8 gen) 		Skylake (9 gen),
Kaby Lake (9.5 gen)
Maximum feature level 12_1 11_1 12_0 11_0 12_1 11_1 12_1
Resource binding[32] Tier 3 Tier 3 Tier 2 Tier 1 Tier 3
Tiled resources[33] Tier 3 Tier 1 Tier 2 Tier 1 Tier 3 No Tier 1 Tier 3
Typed UAV loads for additional formats[34] Yes Yes No Yes No Yes
Conservative rasterization[35] Tier 3 No No Tier 1 Tier 2 No Tier 3
Rasterizer-ordered views[36] Yes No No Yes Yes
Stencil reference value from Pixel Shader[37] Yes Yes No No Yes
UAV slots for all stages[32] full heap full heap 64 64 full heap
Logical blend operations[38][39] Yes Yes Yes Yes
Double precision (64-bit) floating point operations[40][41] Yes Yes Yes Yes
Minimum floating point precision[39][42] 10 or 16 bit 32 bit 16 bit 32 bit 16 bit 32 bit 16 bit
Resource heap[43] Tier 2 Tier 2 Tier 1 Tier 2

See also

References

  1. 1 2 3 "Direct3D 11 on Downlevel Hardware". MSDN. Retrieved 2012-11-18.
  2. ↑ "Windows Driver Kit - Supporting Direct3D 11". MSDN. Retrieved 2009-06-13.
  3. 1 2 3 4 Chuck Walbourn (June 20, 2012). "Direct3D Feature Levels". Games for Windows and the DirectX SDK Blog.
  4. ↑ "Gamefest 2008 Presentations". Microsoft.
  5. ↑ "Direct3D feature levels". MSDN. Retrieved 2012-07-02.
  6. ↑ "GameFest 2008: Introduction to the Direct3D 11 Graphics Pipeline". Microsoft. Slide 56.
  7. ↑ "D3D10_FEATURE_LEVEL1 enumeration". MSDN. Retrieved 2009-11-22.
  8. ↑ "Direct3D feature levels". MSDN. Retrieved 30 September 2014.
  9. ↑ "10Level9 reference". MSDN. Retrieved 2012-11-18.
  10. ↑ MSDN - DirectX and Gaming - Asm Shader Reference
  11. 1 2 https://msdn.microsoft.com/en-us/library/windows/desktop/hh404562#check_support_of_new_direct3d_11.1_features_and_formats
  12. ↑ "MSDN Blogs". Retrieved 30 September 2014.
  13. ↑ https://msdn.microsoft.com/en-us/library/windows/desktop/jj863687.aspx
  14. ↑ Bennett Sorbo (June 26, 2013). "What's New in Direct3D 11.2". Channel9 - BUILD 2013.
  15. ↑ "Samsung Announces A15/Mali-T604 Based Exynos 5 Dual". AnandTech. Retrieved 2013-06-15.
  16. ↑ "Vivante Vega Cores for 3D". Vivante. Retrieved 2014-12-10.
  17. ↑ https://msdn.microsoft.com/en-us/library/dn933277(v=vs.85).aspx
  18. ↑ "D3D11_CONSERVATIVE_RASTERIZATION_TIER enumeration". MSDN library. 22 February 2015. Retrieved 22 February 2015.
  19. ↑ "Direct3D 11.3 Features". MSDN library. 28 March 2015. Retrieved 28 March 2015.
  20. 1 2 Ryan Smith. "AnandTech - The NVIDIA GeForce GTX 980 Review: Maxwell Mark 2". Retrieved 30 September 2014. First and foremost among Maxwell 2’s new features is the inclusion of full Direct3D 11.2/11.3 compatibility.
  21. 1 2 Ryan Smith. "AnandTech - Microsoft Details Direct3D 11.3 & 12 New Rendering Features". Retrieved 30 September 2014.
  22. 1 2 "Maxwell and DX12 Delivered". NVIDIA. Retrieved 30 September 2014.
  23. 1 2 "MSDN Blogs". Retrieved 30 September 2014.
  24. 1 2 http://devblogs.nvidia.com/parallelforall/maxwell-most-advanced-cuda-gpu-ever-made/
  25. 1 2 "Intel Skylake: Core i7-6700K und i5-6600K im Test". PC GAMES HARDWARE ONLINE. 5 August 2015. Retrieved 5 August 2015.
  26. ↑ GVCS005 - Microsoft Direct3D 12: New API Details and Intel Optimizations
  27. ↑ Build 2015: Advanced DirectX12 Graphics and Performance
  28. ↑ https://msdn.microsoft.com/en-us/library/dn899127.aspx
  29. ↑ https://msdn.microsoft.com/en-us/library/mt733232(v=vs.85).aspx
  30. ↑ https://msdn.microsoft.com/en-us/library/windows/desktop/ff476900(v=vs.85).aspx
  31. ↑ Wolfgang Engel. Introduction to Resource Binding in Microsoft DirectX 12
  32. 1 2 https://msdn.microsoft.com/en-us/library/dn899110(v=vs.85).aspx
  33. ↑ https://msdn.microsoft.com/en-us/library/dn903951(v=vs.85).aspx
  34. ↑ https://msdn.microsoft.com/en-us/library/dn903947(v=vs.85).aspx
  35. ↑ https://msdn.microsoft.com/en-us/library/dn903791(v=vs.85).aspx
  36. ↑ https://msdn.microsoft.com/en-us/library/dn903929(v=vs.85).aspx
  37. ↑ https://msdn.microsoft.com/en-us/library/dn913201(v=vs.85).aspx
  38. ↑ https://msdn.microsoft.com/en-us/library/windows/desktop/hh404562(v=vs.85).aspx#use_logical_operations_in_a_render_target
  39. 1 2 https://msdn.microsoft.com/en-us/library/dn859253(v=vs.85).aspx
  40. ↑ https://msdn.microsoft.com/en-us/library/windows/desktop/ff476127(v=vs.85).aspx
  41. ↑ https://msdn.microsoft.com/en-us/library/windows/hardware/dn653328(v=vs.85).aspx#dblshader
  42. ↑ https://msdn.microsoft.com/en-us/library/windows/desktop/hh404562(v=vs.85).aspx#Min_Precision
  43. ↑ https://msdn.microsoft.com/en-us/library/dn986743(v=vs.85).aspx

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