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SampleGrad (DirectX HLSL Texture Object)

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Samples a texture using a gradient to influence the way the sample location is calculated.

<Template Type> Object.SampleGrad( sampler_state S, float Location, float DDX, float DDY [, int Offset] );

Parameters

Item Description
Object
 Any texture-object type (except Texture2DMS and Texture2DMSArray).
S
 [in] A Sampler state. This is an object declared in an effect file that contains state assignments.
Location
 [in] The Texture coordinates. The argument type is dependent on the texture-object type.
Texture-Object Type Parameter Type
Texture1D float
Texture1DArray, Texture2D float2
Texture2DArray, Texture3D, TextureCube float3
TextureCubeArray float4
Texture2DMS, Texture2DMSArray not supported

DDX

[in] The rate of change of the surface geometry in the x direction. The argument type is dependent on the texture-object type.

Texture-Object Type Parameter Type
Texture1D, Texture1DArray float
Texture2D, Texture2DArray float2
Texture3D, TextureCube, TextureCubeArray float3
Texture2DMS, Texture2DMSArray not supported

DDY

[in] The rate of change of the surface geometry in the y direction. The argument type is dependent on the texture-object type.

Texture-Object Type Parameter Type
Texture1D, Texture1DArray float
Texture2D, Texture2DArray float2
Texture3D, TextureCube, TextureCubeArray float3
Texture2DMS, Texture2DMSArray not supported

Offset

[in] An optional texture coordinate offset, which can be used for any texture-object types. The offset is applied to the location before sampling. Use an offset only at an integer miplevel; otherwise, you may get results that do not translate well to hardware. The argument type is dependent on the texture-object type. For more info, seeApplying Integer Offsets.

Texture-Object Type Parameter Type
Texture1D, Texture1DArray int
Texture2D, Texture2DArray int2
Texture3D int3
TextureCube, TextureCubeArray not supported
Texture2DMS, Texture2DMSArray not supported

Return Value

The texture's template type, which may be a single- or multi-component vector. The format is based on the texture's DXGI_FORMAT.

Minimum Shader Model

This function is supported in the following shader models.

vs_4_0 vs_4_1 ps_4_0 ps_4_1 gs_4_0 gs_4_1
x x x x x x
  1. TextureCubeArray is available in Shader Model 4.1 or higher.
  2. Shader Model 4.1 is available in Direct3D 10.1 or higher.

Example

This partial code example is from the MotionBlur.fx file in the MotionBlur10 Sample.

// Object Declarations
Texture2D g_txDiffuse;

SamplerState g_samLinear
{
    Filter = ANISOTROPIC;
    MaxAnisotropy = 8;
    AddressU = Wrap;
    AddressV = Wrap;
};

struct VSSceneOut
{
    float4 Pos : SV_POSITION;
    float4 Color : COLOR0;
    float2 Tex : TEXCOORD;
    float2 Aniso : ANISOTROPY;
};

float4 PSSceneMain( VSSceneOut Input ) : SV_TARGET
{
    float2 ddx = Input.Aniso;
    float2 ddy = Input.Aniso;
    
    // Shader body calling the intrinsic function
    float4 diff = g_txDiffuse.SampleGrad( g_samLinear, Input.Tex, ddx, ddy);
    
    ...
}

Texture-Object