Samples a 3D texture using a gradient to select the mip level.
|ret tex3D(s, t, ddx, ddy)|
[in] The sampler state.
[in] The texture coordinate.
[in] Rate of change of the surface geometry in the x direction.
[in] Rate of change of the surface geometry in the y direction.
The value of the texture data.
|Name||In/Out||Template Type||Component Type||Size|
This function is supported in the following shader models.
|Shader Model 4||yes (pixel shader only)|
|Shader Model 3 (DirectX HLSL)||yes¹ (pixel shader only)|
|Shader Model 2 (DirectX HLSL)||yes² (pixel shader only)|
|Shader Model 1 (DirectX HLSL)||no|
- Significant code reordering is done to move gradient computations outside of flow control.
- If the D3DPSHADERCAPS2_0 cap is set with D3DD3DPSHADERCAPS2_0_GRADIENTINSTRUCTIONS, the compiler maps this function to texldd.
When flow control is present in a shader, the result of a gradient calculation requested inside a given branch path is ambiguous when adjacent pixels may go down separate flow control paths. Therefore, it is deemed illegal to use any pixel shader operation that requests a gradient calculation to occur at a location that is inside a flow control construct which could vary across pixels for a given primitive being rasterized. If either side of an if statement with the branch attribute uses a gradient function a compiler error may be generated. See if Statement (DirectX HLSL).