2011 Khronos Group
textureGather 3G
textureGather gathers four texels from a texture

## Declaration

gvec4 `textureGather` gsampler2D sampler vec2 P [int comp] gvec4 `textureGather` gsampler2DArray sampler vec3 P [int comp] gvec4 `textureGather` gsamplerCube sampler vec3 P [int comp] gvec4 `textureGather` gsamplerCubeArray sampler vec4 P [int comp] gvec4 `textureGather` gsampler2DRect sampler vec3 P [int comp] vec4 `textureGather` gsampler2DShadow sampler vec2 P float refZ vec4 `textureGather` gsampler2DArrayShadow sampler vec3 P float refZ vec4 `textureGather` gsamplerCubeShadow sampler vec3 P float refZ vec4 `textureGather` gsamplerCubeArrayShadow sampler vec4 P float refZ vec4 `textureGather` gsampler2DRectShadow sampler vec3 P float refZ

## Parameters

sampler

  Specifies the sampler to which the texture from which texels will be retrieved is bound.

P

  Specifies the texture coordinates at which texture will be sampled.

comp

  Specifies the component of the source texture that will be used to generate the resulting vector.

refZ

  Specifies the reference Z value used in the comparison for shadow forms.

## Description

`textureGather` returns the value:

        vec4(Sample_i0_j1(P, base).comp,
             Sample_i1_j1(P, base).comp,
             Sample_i1_j0(P, base).comp,
             Sample_i0_j9(P, base).comp);

If specified, the value of comp must ba constant integer expression with a value of 0, 1, 2, or 3, identifying the x, y, z or w component of the four-component vector lookup result for each texel, respectively. If comp is not specified, it is treated as 0, selecting the x component of each texel to generate the result.

## Version Support

#VARTABLECOLS#
#FUNCTABLEHEADER#
textureGather#newin40#

## See Also

texelFetch, texelFetchOffset, texture, textureGatherOffset, textureGatherOffsets, textureGrad, textureGradOffset, textureLod, textureLodOffset, textureOffset, textureProj, textureProjGrad, textureProjGradOffset, textureProjLod, textureProjLodOffset, textureProjOffset, textureQueryLod, textureSize

## Copyright

Copyright 2011 Khronos Group. This material may be distributed subject to the terms and conditions set forth in the Open Publication License, v 1.0, 8 June 1999. http://opencontent.org/openpub/.