NAME

       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_j1(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

       ┌──────────────┬───────────────────────────────────────────────────────────────────────────────────┐
       │              │        OpenGL Shading Language Version                                            │
       ├──────────────┼──────┬──────┬──────┬──────┬──────┬──────┬──────┬──────┬──────┬──────┬──────┬──────┤
       │Function      │ 1.10 │ 1.20 │ 1.30 │ 1.40 │ 1.50 │ 3.30 │ 4.00 │ 4.10 │ 4.20 │ 4.30 │ 4.40 │ 4.50 │
       │Name          │      │      │      │      │      │      │      │      │      │      │      │      │
       ├──────────────┼──────┼──────┼──────┼──────┼──────┼──────┼──────┼──────┼──────┼──────┼──────┼──────┤
       │textureGather │  -   │  -   │  -   │  -   │  -   │  -   │  ✔   │  ✔   │  ✔   │  ✔   │  ✔   │  ✔   │
       └──────────────┴──────┴──────┴──────┴──────┴──────┴──────┴──────┴──────┴──────┴──────┴──────┴──────┘

SEE ALSO

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

COPYRIGHT

       Copyright © 2011-2014 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/.

COPYRIGHT

       Copyright © 2011-2014 Khronos Group

[FIXME: source]                             01/03/2018                          TEXTUREGATHER(3G)