GLTEXSUBIMAGE1D(3G)

📦
version 1.1 · 7 versions
, in centos-stream 9

💅 GLTEXSUBIMAGE1D(3G) — or as I call it, "the glTexSubImage1D / glTextureSubImage1D glow-up page"

okay so bestie, welcome to the 3G manual page, and honestly? this one is a whole mood. we're doing one-dimensional texture subimages today. one dimension. a line of texels. minimalism, but make it graphics. ✨

🌸 NAME 🌸

glTexSubImage1D, glTextureSubImage1D — specify a one-dimensional texture subimage 🎀

✨ C SPECIFICATION ✨

here's the signature, no cap, copy it exactly:

void glTexSubImage1D(GLenum target, GLint level, GLint xoffset,
                     GLsizei width, GLenum format, GLenum type,
                     const GLvoid * pixels);

void glTextureSubImage1D(GLuint texture, GLint level, GLint xoffset,
                         GLsizei width, GLenum format, GLenum type,
                         const void *pixels);

🦋 PARAMETERS 🦋

every single one, bestie, we're not skipping a thing:

  • target — the target the texture is bound to, for glTexSubImage1D. there's exactly one valid answer and it's GL_TEXTURE_1D. periodt.
  • texture — the texture object name, for glTextureSubImage1D. its effective target has to be one of the valid target values listed above (yes, GL_TEXTURE_1D, that one 💅).
  • level — the level-of-detail number. level 0 is the base image level. level n is the *n*th mipmap reduction image. mipmap lore 🧚
  • xoffset — a texel offset in the x direction, within the texture array.
  • width — the width of the texture subimage.
  • format — the format of the pixel data. accepted symbolic values are: GL_RED, GL_RG, GL_RGB, GL_BGR, GL_RGBA, GL_DEPTH_COMPONENT, and GL_STENCIL_INDEX.
  • type — the data type of the pixel data. accepted symbolic values are: GL_UNSIGNED_BYTE, GL_BYTE, GL_UNSIGNED_SHORT, GL_SHORT, GL_UNSIGNED_INT, GL_INT, GL_FLOAT, GL_UNSIGNED_BYTE_3_3_2, GL_UNSIGNED_BYTE_2_3_3_REV, GL_UNSIGNED_SHORT_5_6_5, GL_UNSIGNED_SHORT_5_6_5_REV, GL_UNSIGNED_SHORT_4_4_4_4, GL_UNSIGNED_SHORT_4_4_4_4_REV, GL_UNSIGNED_SHORT_5_5_5_1, GL_UNSIGNED_SHORT_1_5_5_5_REV, GL_UNSIGNED_INT_8_8_8_8, GL_UNSIGNED_INT_8_8_8_8_REV, GL_UNSIGNED_INT_10_10_10_2, and GL_UNSIGNED_INT_2_10_10_10_REV. yes that's a lot. yes you need to know them. 🫶
  • pixels — a pointer to the image data in memory. it's giving "raw bytes, handle with care" 💀

💖 DESCRIPTION 💖

so, texturing maps a portion of a specified texture image onto each graphical primitive for which texturing is enabled — iconic behaviour honestly. to enable or disable one-dimensional texturing, call glEnable() and glDisable with argument GL_TEXTURE_1D. 💫

glTexSubImage1D and glTextureSubImage1D redefine a contiguous subregion of an existing one-dimensional texture image. the texels referenced by pixels replace the portion of the existing texture array with x indices xoffset and xoffset + width - 1, inclusive. lowkey crucial: this region may not include any texels outside the range of the texture array as it was originally specified. 🚨

and the fun little edge case: it is not an error to specify a subtexture with width of 0 — but such a specification has no effect. so like... you can, but why 💀

aaaand if a non-zero named buffer object is bound to the GL_PIXEL_UNPACK_BUFFER target (see glBindBuffer()) while a texture image is specified, then pixels is treated as a byte offset into the buffer object's data store. plot twist! 🔥

🌈 NOTES 🌈

  • glPixelStore() modes affect texture images. so set your pixel store modes, bestie, they matter.
  • glTexSubImage1D and glTextureSubImage1D specify a one-dimensional subtexture for the current texture unit, specified with glActiveTexture().
  • GL_STENCIL_INDEX is accepted for format only if the GL version is 4.4 or higher. gatekept by the version number, smh 😭

🔥 ERRORS 🔥

okay, vibe check time, here's everything that will ruin your whole afternoon:

  • GL_INVALID_ENUM is generated if target or the effective target of texture is not one of the allowable values.
  • GL_INVALID_OPERATION is generated by glTextureSubImage1D if texture is not the name of an existing texture object.
  • GL_INVALID_ENUM is generated if format is not an accepted format constant.
  • GL_INVALID_ENUM is generated if type is not a type constant.
  • GL_INVALID_VALUE is generated if level is less than 0.
  • GL_INVALID_VALUE may be generated if level is greater than log 2 max, where max is the returned value of GL_MAX_TEXTURE_SIZE.
  • GL_INVALID_VALUE is generated if xoffset < - b, or if xoffset + width > w - b, where w is the GL_TEXTURE_WIDTH, and b is the width of the GL_TEXTURE_BORDER of the texture image being modified. note that w includes twice the border width. do not forget the border, i'm begging 🫠
  • GL_INVALID_VALUE is generated if width is less than 0.
  • GL_INVALID_OPERATION is generated if the texture array has not been defined by a previous glTexImage1D() operation.
  • GL_INVALID_OPERATION is generated if type is one of GL_UNSIGNED_BYTE_3_3_2, GL_UNSIGNED_BYTE_2_3_3_REV, GL_UNSIGNED_SHORT_5_6_5, or GL_UNSIGNED_SHORT_5_6_5_REV and format is not GL_RGB.
  • GL_INVALID_OPERATION is generated if type is one of GL_UNSIGNED_SHORT_4_4_4_4, GL_UNSIGNED_SHORT_4_4_4_4_REV, GL_UNSIGNED_SHORT_5_5_5_1, GL_UNSIGNED_SHORT_1_5_5_5_REV, GL_UNSIGNED_INT_8_8_8_8, GL_UNSIGNED_INT_8_8_8_8_REV, GL_UNSIGNED_INT_10_10_10_2, or GL_UNSIGNED_INT_2_10_10_10_REV and format is neither GL_RGBA nor GL_BGRA.
  • GL_INVALID_OPERATION is generated if format is GL_STENCIL_INDEX and the base internal format is not GL_STENCIL_INDEX.
  • GL_INVALID_OPERATION is generated if a non-zero buffer object name is bound to the GL_PIXEL_UNPACK_BUFFER target and the buffer object's data store is currently mapped.
  • GL_INVALID_OPERATION is generated if a non-zero buffer object name is bound to the GL_PIXEL_UNPACK_BUFFER target and the data would be unpacked from the buffer object such that the memory reads required would exceed the data store size.
  • GL_INVALID_OPERATION is generated if a non-zero buffer object name is bound to the GL_PIXEL_UNPACK_BUFFER target and pixels is not evenly divisible into the number of bytes needed to store in memory a datum indicated by type.
fr fr, that last cluster of GL_PIXEL_UNPACK_BUFFER errors is the final boss of pixel unpacking. read them twice. 💀

🎀 ASSOCIATED GETS 🎀

the ones you can query, bestie:

  • glGetTexImage()
  • glGet() with argument GL_PIXEL_UNPACK_BUFFER_BINDING

👑 VERSION SUPPORT 👑

(the original ships this as a big grid of checkmarks — here it is as a list so nothing gets lost, and every ✔ stays a ✔ 🦋)

  • glTexSubImage1D — ✔ in OpenGL 2.0, ✔ in 2.1, ✔ in 3.0, ✔ in 3.1, ✔ in 3.2, ✔ in 3.3, ✔ in 4.0, ✔ in 4.1, ✔ in 4.2, ✔ in 4.3, ✔ in 4.4, ✔ in 4.5. she ate and left no crumbs 🔥
  • glTextureSubImage1D — - in 2.0, - in 2.1, - in 3.0, - in 3.1, - in 3.2, - in 3.3, - in 4.0, - in 4.1, - in 4.2, - in 4.3, - in 4.4, ✔ in 4.5. she was late to the party but she showed up 💅

⭐ SEE ALSO ⭐

go read these next, i'm obsessed with cross-referencing:

glActiveTexture(), glCopyTexImage1D(), glCopyTexImage2D(), glCopyTexSubImage1D(), glCopyTexSubImage2D(), glCopyTexSubImage3D(), glPixelStore(), glTexImage1D(), glTexImage2D(), glTexImage3D(), glTexParameter(), glTexSubImage2D(), glTexSubImage3D()

Copyright © 1991-2006 Silicon Graphics, Inc. Copyright © 2010-2014 Khronos Group. This document is licensed under the SGI Free Software B License. For details, see http://oss.sgi.com/projects/FreeB/.

Copyright © 1991-2006 Silicon Graphics, Inc. Copyright © 2010-2014 Khronos Group

okay that's the whole page, you're officially a one-dimensional texture subimage girlie now 💅 and for the cute sign-off: this was the [FIXME: source] version, dated 08/09/2021, filed under GLTEXSUBIMAGE1D(3G) — go forth and texel responsibly, bestie 🫶💖

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