SampleLevel (DirectX HLSL Texture Object)

Samples a texture using a mipmap-level offset.

DXGI_FORMAT Object.SampleLevel(

sampler_state S,

float Location,

float LOD

[, int Offset]

);

 

This function is similar to Sample except that it uses the LOD level (in the last component of the location parameter) to choose the mipmap level. For example, a 2D texture uses the first two components for uv coordinates and the third component for the mipmap level.

Parameters

ItemDescription

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 TypeParameter Type
Texture1Dfloat
Texture1DArray, Texture2Dfloat2
Texture2DArray, Texture3D, TextureCubefloat3
TextureCubeArray¹float4

 

If the texture object is an array, the last component is the array index.

LOD

[in] A number that specifies the mipmap level. If the value is ≤ 0, the zero'th (biggest map) is used. The fractional value (if supplied) is used to interpolate between two mipmap levels.

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, see Applying Integer Offsets.

Texture-Object TypeParameter Type
Texture1D, Texture1DArrayint
Texture2D, Texture2DArrayint2
Texture3Dint3
TextureCube, TextureCubeArray¹not supported

 

 

Return Value

The texture format which is one of the typed values listed in DXGI_FORMAT.

Minimum Shader Model

This function is supported in the following shader models.

vs_4_0vs_4_1²ps_4_0ps_4_1²gs_4_0gs_4_1²
xxxxxx

 

  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 Instancing.fx file in the Instancing10 Sample.



// Object Declarations
Texture1D g_txRandom;

SamplerState g_samPoint
{
    Filter = MIN_MAG_MIP_POINT;
    AddressU = Wrap;
    AddressV = Wrap;
};

	
// Shader body calling the intrinsic function
float3 RandomDir(float fOffset)
{   
    float tCoord = (fOffset) / 300.0;
    return g_txRandom.SampleLevel( g_samPoint, tCoord, 0 );
   ...



Related topics

Texture-Object

 

 

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