| Issue |
184482
|
| Summary |
[Matrix] Implement matrix support for the `fwidth` HLSL Function
|
| Labels |
HLSL,
bot:HLSL
|
| Assignees |
|
| Reporter |
kmpeng
|
> Note: This issue tracks matrix support for `fwidth`. The original implementation issue is [here](https://github.com/llvm/llvm-project/issues/99120).
Matrix requirements:
- [ ] https://github.com/llvm/wg-hlsl/issues/387
## HLSL:
Returns the absolute value of the partial derivatives of the specified value.
| *ret* fwidth(*x*) |
|-------------------|
This function computes the following: [**abs**](https://github.com/MicrosoftDocs/win32/blob/docs/desktop-src//direct3dhlsl/dx-graphics-hlsl-abs.md)([**ddx**](https://github.com/MicrosoftDocs/win32/blob/docs/desktop-src//direct3dhlsl/dx-graphics-hlsl-ddx.md)(*x*)) + [**abs**](https://github.com/MicrosoftDocs/win32/blob/docs/desktop-src//direct3dhlsl/dx-graphics-hlsl-abs.md)([**ddy**](https://github.com/MicrosoftDocs/win32/blob/docs/desktop-src//direct3dhlsl/dx-graphics-hlsl-ddy.md)(*x*)).
This function is only supported in pixel shaders.
## Parameters
| Item | Description |
|--------------------------------------------------------|----------------------------------------|
| <span id="x"></span><span id="X"></span>*x*<br/> | \[in\] The specified value.<br/> |
## Return Value
The absolute value of the partial derivatives of the *x* parameter.
## Type Description
| Name | [**Template Type**](https://github.com/MicrosoftDocs/win32/blob/docs/desktop-src//direct3dhlsl/dx-graphics-hlsl-intrinsic-functions.md) | [**Component Type**](https://github.com/MicrosoftDocs/win32/blob/docs/desktop-src//direct3dhlsl/dx-graphics-hlsl-intrinsic-functions.md) | Size |
|-------|----------------------------------------------------------------------------------------------------------------|----------------------------------------------------------------|--------------------------------|
| *x* | [**scalar**](https://github.com/MicrosoftDocs/win32/blob/docs/desktop-src//direct3dhlsl/dx-graphics-hlsl-intrinsic-functions.md), **vector**, or **matrix** | [**float**](https://github.com/MicrosoftDocs/win32/blob/docs/desktop-src/WinProg/windows-data-types.md) | any |
| *ret* | same as input *x* | [**float**](https://github.com/MicrosoftDocs/win32/blob/docs/desktop-src/WinProg/windows-data-types.md) | same dimension(s) as input *x* |
## Minimum Shader Model
This function is supported in the following shader models.
| Shader Model | Supported |
|------------------------------------------------------------------------------------|---------------------|
| [Shader Model 3 (DirectX HLSL)](https://github.com/MicrosoftDocs/win32/blob/docs/desktop-src//direct3dhlsl/dx-graphics-hlsl-sm3.md) and higher shader models | yes |
| [Shader Model 2 (DirectX HLSL)](https://github.com/MicrosoftDocs/win32/blob/docs/desktop-src//direct3dhlsl/dx-graphics-hlsl-sm2.md) | yes (ps\_2\_x only) |
| [Shader Model 1 (DirectX HLSL)](https://github.com/MicrosoftDocs/win32/blob/docs/desktop-src//direct3dhlsl/dx-graphics-hlsl-sm1.md) | no |
## See also
<dl> <dt>
[**Intrinsic Functions (DirectX HLSL)**](https://github.com/MicrosoftDocs/win32/blob/docs/desktop-src//direct3dhlsl/dx-graphics-hlsl-intrinsic-functions.md)
</dt> </dl>
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