2011 Khronos Group
textureGatherOffset 3G
textureGatherOffset gathers four texels from a texture with offset

## Declaration

gvec4 `textureGatherOffset` gsampler2D sampler vec2 P ivec2 offset [int comp] gvec4 `textureGatherOffset` gsampler2DArray sampler vec3 P ivec2 offset [int comp] gvec4 `textureGatherOffset` gsampler2DRect sampler vec3 P ivec2 offset [int comp] vec4 `textureGatherOffset` gsampler2DShadow sampler vec2 P float refZ ivec2 offset vec4 `textureGatherOffset` gsampler2DArrayShadow sampler vec3 P float refZ ivec2 offset vec4 `textureGatherOffset` gsampler2DRectShadow sampler vec3 P float refZ ivec2 offset

## 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.

offset

  Specifies the offset from the specified texture coordinate P from which the texels will be gathered.

## Description

`textureGatherOffset` returns the value:

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

It perfoms as textureGather but with offset applied as described in textureOffset, except that the implementation-dependent minimum and maximum offset values are given by `GL_MIN_PROGRRAM_TEXTURE_GATHER_OFFSET` and `GL_MAX_PROGRAM_TEXTURE_GATHER_OFFSET`, respectively.

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#
textureGatherOffset#newin40#

## See Also

texelFetch, texelFetchOffset, texture, textureGather, 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/.