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Returns the partial derivative of the specified value with respect to the screen-space x-coordinate.
| ret ddx(x) |
|---|
This function computes the partial derivative with respect to the screen-space x-coordinate. To compute the partial derivative with respect to the screen-space y-coordinate, use the ddy function.
This function is supported only in pixel shaders.
Parameters
| Item | Description |
|---|---|
| x |
[in] The specified value. |
Return Value
The partial derivative of the x parameter.
Type Description
| Name | Template Type | Component Type | Size |
|---|---|---|---|
| x | scalar, vector, or matrix | float | any |
| ret | same as input x | float | same dimension(s) as input x |
Minimum Shader Model
This function is supported in the following shader models.
| Shader Model | Supported |
|---|---|
| Shader Model 5 and higher shader models | yes |
| Shader Model 4 | yes |
| Shader Model 3 (DirectX HLSL) | yes |
| Shader Model 2 (DirectX HLSL) | yes in ps_2_x; unsupported in ps_2_0. |
| Shader Model 1 (DirectX HLSL) | no |
This function is supported in the following types of shaders:
| Vertex | Hull | Domain | Geometry | Pixel | Compute |
|---|---|---|---|---|---|
| x |