Feature Levels
Direct3D 10.1 API introduces a concept of "feature levels" which encapsulate features of the hardware supported in a particular version of the API, with separate levels for 10.0 and 10.1 hardware. In previous releases of the Direct3D API, certain capabilities of the graphics hardware have been synonymous with main revision number of the API.
In Direct3D 11, the concept has been further expanded to run on most downlevel hardware including Direct3D 9 cards with WDDM drivers.
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 runtine. Each upper level is a strict superset of a lower level, with only a few optional features. More advanced features such as new shader models and rendering stages are only exposed on up-level hardware, however the hardware is not required to support all of these feature levels.
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 9.0a 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. "10 Level 9" feature levels contain a subset of the Direct3D 10/11 API 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 of Shader Model 2.0; SM 3.0 (vs_3_0/ps_3_0) has been omitted deliberately in D3D 10 Level 9, although it's available for levels 10_0 and higher.
| Level | Hardware requirements | Supported GPUs |
|---|---|---|
| 9_1 | WDDM 1.0 or later. 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. |
Intel G965 chipset, NVidia GeForce FX |
| 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. |
NVidia GeForce 6600, ATI Radeon X1300 |
| 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, optional DirectCompute (CS 4.0), full floating-point format support, all 9_3 features. | ATI Radeon HD2000 series; NVidia GeForce 8/9/GTX 200 series, Intel GM965 chipset, Intel HD Graphics (Arrandale/Clarkdale) |
| 10_1 | Shader Model 4.1, cubemap arrays, extended MSAA, optional DirectCompute (CS 4.1), all 10_0 features. | ATI Radeon HD 3000/4000 series; NVIDIA GTX 210/220; Intel HD Graphics 3000/2000 (Sandy Bridge) |
| 11_0 | WDDM 1.1 or later. Shader Model 5.0, hull & domain shaders, mandatory DirectCompute (CS 5.0), 16K textures, BC6H/BC7, all 10_1 features. | AMD Radeon HD 5000/6000/7000 series; NVidia GeForce GTX 400/500/600 series; Intel HD Graphics 4000/2500 (Ivy Bridge) |
| 11_1 | WDDM 1.2 or later. SM5.0 with optional extensions, logical blend operations, target-independent rasterization, UAVs at every stage, constant buffer offsetting and partial updates, UAV only rendering with force sample count, all 11_0 features. | AMD HD 7000/8000 series, NVidia GeForce 700 series, Intel HD Graphics GTx (Haswell) |
Read more about this topic: Microsoft Direct3D
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