llvm / llvm/llvm-project

[Matrix] Implement matrix support for the `clip` HLSL Function

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backend:DirectX backend:SPIR-V bot:HLSL clang:codegen clang:frontend HLSL
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Description

> Note: This issue tracks matrix support for `clip`. The original implementation issue is [here](https://github.com/llvm/llvm-project/issues/99093).

Matrix requirements:
- [ ] https://github.com/llvm/wg-hlsl/issues/387

## HLSL:

Discards the current pixel if the specified value is less than zero.

| clip(*x*) |
|-----------|

## Parameters

| Item | Description |
|--------------------------------------------------------|----------------------------------------|
| *x*
| \[in\] The specified value.
|

## Return Value

None.

## Remarks

Use the **clip** HLSL intrinsic function to simulate clipping planes if each component of the *x* parameter represents the distance from a plane.

Also, use the **clip** function to test for alpha behavior, as shown in the following example:

```
clip( Input.Color.A < 0.1f ? -1:1 );
```

## 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 |

## Minimum Shader Model

This function is supported in the following shader models.

| Shader Model | Supported |
|-----------------------------------------------------------|-------------------------|
| [Shader Model 4](https://github.com/MicrosoftDocs/win32/blob/docs/desktop-src//direct3dhlsl/dx-graphics-hlsl-sm4.md) | yes (pixel shader only) |
| [Shader Model 3 (DirectX HLSL)](https://github.com/MicrosoftDocs/win32/blob/docs/desktop-src//direct3dhlsl/dx-graphics-hlsl-sm3.md) | yes (pixel shader only) |
| [Shader Model 2 (DirectX HLSL)](https://github.com/MicrosoftDocs/win32/blob/docs/desktop-src//direct3dhlsl/dx-graphics-hlsl-sm2.md) | yes (pixel shader only) |
| [Shader Model 1 (DirectX HLSL)](https://github.com/MicrosoftDocs/win32/blob/docs/desktop-src//direct3dhlsl/dx-graphics-hlsl-sm1.md) | yes (pixel shader only) |

## See also

[**Intrinsic Functions (DirectX HLSL)**](https://github.com/MicrosoftDocs/win32/blob/docs/desktop-src//direct3dhlsl/dx-graphics-hlsl-intrinsic-functions.md)

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