TEXTURE(3G)

💖 TEXTURE(3G) 💖

okay bestie, pull up a chair, grab a boba, because we're doing the texture manual page from the 3G section and honestly?? it's giving main character energy ✨. this is the one that snatches texels out of a texture. yes. that's the whole job. let's get into it 🫶

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🌸 NAME 🌸

texture — retrieves texels from a texture

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✨ DECLARATION ✨

like, there are so many overloads here and every single one of them is iconic in its own way. no cap, here's the full lineup, exactly as written:

gvec4 texture(gsampler1D sampler, float P, [float bias]);

gvec4 texture(gsampler2D sampler, vec2 P, [float bias]);

gvec4 texture(gsampler3D sampler, vec3 P, [float bias]);

gvec4 texture(gsamplerCube sampler, vec3 P, [float bias]);

float texture(sampler1DShadow sampler, vec3 P, [float bias]);

float texture(sampler2DShadow sampler, vec3 P, [float bias]);

float texture(samplerCubeShadow sampler, vec3 P, [float bias]);

gvec4 texture(gsampler1DArray sampler, vec2 P, [float bias]);

gvec4 texture(gsampler2DArray sampler, vec3 P, [float bias]);

gvec4 texture(gsamplerCubeArray sampler, vec4 P, [float bias]);

float texture(sampler1DArrayShadow sampler, vec3 P, [float bias]);

float texture(gsampler2DArrayShadow sampler, vec4 P, [float bias]);

gvec4 texture(gsampler2DRect sampler, vec2 P);

float texture(sampler2DRectShadow sampler, vec3 P);

float texture(gsamplerCubeArrayShadow sampler, vec4 P, float compare);

notice how the gsampler2DRect and sampler2DRectShadow ones have no bias?? that's not a typo bestie, that's canon. 💅

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🎀 PARAMETERS 🎀

• sampler — the sampler that's holding onto the texture we're gonna steal texels from. it's literally the plug. 🔌
• P — the texture coordinates where we're sampling. this is where the vibe check happens.
• bias — an optional bias that gets applied during level-of-detail computation. optional but lowkey important.
• compare — the value that the fetched texel gets compared against when you're sampling from gsamplerCubeArrayShadow. yes, specifically that one. no, not the others.

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🦋 DESCRIPTION 🦋

so texture samples texels from the texture bound to sampler, at texture coordinate P. and if you pass in that optional bias, it gets folded into the level-of-detail computation — which is the thing that decides which mipmap(s) we're pulling from. mipmap selection is a whole process and bias gets a vote. 🗳️

now for the shadow forms, and this part is a little fiddly so pay attention bestie:

• when compare is present, it's used as Dsub, and the array layer comes from P.w. that's the fourth component. the w. 🫡
• when compare is not present, the last component of P is used as Dsub, and the array layer comes from the second to last component of P.
• and just so you know — for 1D shadow lookups, the second component of P is unused. it's just sitting there. unemployed. 🙈

and for the non-shadow variants? the array layer comes from the last component of P. simple. clean. slay. ✨

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👑 VERSION SUPPORT 👑

(the original is a big sparkly grid, but we're doing it as a list because tables are not the vibe here — every number is still exactly right, promise 💜)

the columns are OpenGL Shading Language versions: 1.10, 1.20, 1.30, 1.40, 1.50, 3.30, 4.00, 4.10, 4.20, 4.30, 4.40, 4.50. a - means nope, a ✔ means yes bestie.

• texture — 1.10: -, 1.20: -, 1.30: ✔, 1.40: ✔, 1.50: ✔, 3.30: ✔, 4.00: ✔, 4.10: ✔, 4.20: ✔, 4.30: ✔, 4.40: ✔, 4.50: ✔
• texture (gsampler2DRect{Shadow}) — 1.10: -, 1.20: -, 1.30: -, 1.40: ✔, 1.50: ✔, 3.30: ✔, 4.00: ✔, 4.10: ✔, 4.20: ✔, 4.30: ✔, 4.40: ✔, 4.50: ✔
• texture (gsampler2DMS, gsampler2DMSArray) — 1.10: -, 1.20: -, 1.30: -, 1.40: -, 1.50: ✔, 3.30: ✔, 4.00: ✔, 4.10: ✔, 4.20: ✔, 4.30: ✔, 4.40: ✔, 4.50: ✔
• texture (gsamplerCubeArray{Shadow}) — 1.10: -, 1.20: -, 1.30: -, 1.40: -, 1.50: -, 3.30: -, 4.00: ✔, 4.10: ✔, 4.20: ✔, 4.30: ✔, 4.40: ✔, 4.50: ✔

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🌈 SEE ALSO 🌈

the whole friend group, fr fr — go read these too, they're all part of the same era:

• texelFetch()
• texelFetchOffset()
• textureGather()
• textureGatherOffset()
• textureGatherOffsets()
• 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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okay that's the whole page 🎀 and now the cute sign-off: this came from [FIXME: source], dated 01/03/2018, and it lives in the TEXTURE(3G) section of the manual. go forth and sample responsibly, bestie. mwah 💖✨🧚