Built-In Functions - Praise for OpenGL ES 30 Programming Guide - page 480

Table B-9 Texture Lookup Functions (continued)

Syntax Description

Do a texture lookup as in texture but with
offset added to the (u, v, w) texel coordinates
before looking up each texel. The offset value
must be a constant expression. A limited
range of offset values are supported; the
minimum and maximum offset values are
implementation-dependent and given by MIN_
PROGRAM_TEXEL_OFFSET and
MAX_PROGRAM_TEXEL_OFFSET , respectively.
Note that offset does not apply to the layer
coordinate for texture arrays.
Note that texel offsets are also not supported
for cubemaps.

gvec4 textureOffset (gsampler2D sampler , vec2 P ,
ivec2 offset [, float bias ] )
gvec4 textureOffset (gsampler3D sampler , vec3 P ,
ivec3 offset [, float bias ] )
float textureOffset (sampler2DShadow sampler , vec3 P ,
ivec2 offset [, float bias ] )
gvec4 textureOffset (gsampler2DArray sampler , vec3 P ,
ivec2 offset [, float bias ] )

gvec4 textureProjLod (gsampler2D sampler , vec3 P , float lod )
gvec4 textureProjLod (gsampler2D sampler , vec4 P , float lod )
gvec4 textureProjLod (gsampler3D sampler , vec4 P , float lod )
float textureProjLod (sampler2DShadow sampler , vec4 P ,
float lod )

Do a projective texture lookup with explicit
LOD. See textureProj and textureLod .

gvec4 textureProjLodOffset (gsampler2D sampler , vec3 P , float lod ,
ivec2 offset )
gvec4 textureProjLodOffset (gsampler2D sampler , vec4 P , float lod ,
ivec2 offset )
gvec4 textureProjLodOffset (gsampler3D sampler , vec4 P , float lod ,
ivec3 offset )

Do an offset projective texture lookup with
explicit LOD. See textureProj , textureLod ,
and textureOffset .