TEXTUREGATHEROFFSETS(3G)

💖 TEXTUREGATHEROFFSETS 💖

okay bestie, so this is the textureGatherOffsets page from section 3G of the manual — like, the OpenGL Shading Language function pages. It's giving very much "grab four texels at once, but with YOUR OWN custom offsets". Let's get into it 🦋

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✨ NAME ✨

textureGatherOffsets — gathers four texels from a texture with an array of offsets 💅

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🎀 DECLARATION 🎀

no cap, here's exactly how you call her:

gvec4 textureGatherOffsets(gsampler2D sampler, vec2 P, ivec2 offsets[4],
                           [int comp]);

gvec4 textureGatherOffsets(gsampler2DArray sampler, vec3 P,
                           ivec2 offsets[4], [int comp]);

gvec4 textureGatherOffsets(gsampler2DRect sampler, vec3 P,
                           ivec2 offsets[4], [int comp]);

vec4 textureGatherOffsets(gsampler2DShadow sampler, vec2 P, float refZ,
                          ivec2 offsets[4]);

vec4 textureGatherOffsets(gsampler2DArrayShadow sampler, vec3 P,
                          float refZ, ivec2 offsets[4]);

vec4 textureGatherOffsets(gsampler2DRectShadow sampler, vec3 P,
                          float refZ, ivec2 offsets[4]);

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🌸 PARAMETERS 🌸

• sampler — the sampler your texture is bound to, aka the thing we're stealing texels out of 🫶
• P — the texture coordinates where the sampling happens. your little address in texture-space ✨
• comp — which component of the source texture gets used to build the resulting vector. pick your fighter 💅
• refZ — the reference Z value that the comparison uses in the shadow forms. yes ma'am, comparison time 👑
• offsets — an array of offsets from the texture coordinate P, and these are the spots we gather the texels from. literally a lil lineup of coordinates 🎀

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💜 DESCRIPTION 💜

okay so textureGatherOffsets operates identically to textureGatherOffset(), EXCEPT — and this is the whole main character moment — offsets is what decides where the four texels get sampled from. 🌈

Each of the four texels comes from taking the offset in offsets, applying it as a (u, v) coordinate offset to P, finding the four-texel GL_LINEAR footprint that lands on, and then selecting texel i0i0 of that footprint. Four offsets, four texels, one function. iconic behavior fr fr 💖

⚠️ heads up bestie: the values you put in offsets must be set with constant integral expressions. not vibes, not runtime math. constant. integral. expressions. periodt.

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👑 VERSION SUPPORT 👑

so textureGatherOffsets rolled up in OpenGL Shading Language version 4.00 and has been eating ever since. here's the whole timeline, no skipping:

• OpenGL Shading Language 1.10 — - (not here yet 🙈)
• OpenGL Shading Language 1.20 — -
• OpenGL Shading Language 1.30 — -
• OpenGL Shading Language 1.40 — -
• OpenGL Shading Language 1.50 — -
• OpenGL Shading Language 3.30 — -
• OpenGL Shading Language 4.00 — ✔ present and thriving ✨
• OpenGL Shading Language 4.10 — ✔
• OpenGL Shading Language 4.20 — ✔
• OpenGL Shading Language 4.30 — ✔
• OpenGL Shading Language 4.40 — ✔
• OpenGL Shading Language 4.50 — ✔

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🦋 SEE ALSO 🦋

the whole friend group, go say hi 💕

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

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💅 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 © 2011-2014 Khronos Group

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and that's the whole page bestie!! this lil cutie came from [FIXME: source] and the date on it is 01/03/2018, and it lives in section 3G as TEXTUREGATHEROFFSETS. mwah, go gather some texels 💋✨