GLCOPYTEXIMAGE2D(3G)

okay so bestie, welcome to the glCopyTexImage2D page from section 3G of the manual — this is literally the glow-up guide for copying pixels into a 2D texture image, and I'm obsessed 💅✨

✨ NAME ✨

glCopyTexImage2D — copy pixels into a 2D texture image. no cap, that's the whole vibe 🎀

💻 C SPECIFICATION 💻

okay so here's the exact function signature, copy it character for character or it's not gonna slay:

void glCopyTexImage2D(GLenum target, GLint level, GLenum internalformat,
                      GLint x, GLint y, GLsizei width, GLsizei height,
                      GLint border);

🎀 PARAMETERS 🎀

• target — specifies the target texture. has to be one of: GL_TEXTURE_2D, GL_TEXTURE_CUBE_MAP_POSITIVE_X, GL_TEXTURE_CUBE_MAP_NEGATIVE_X, GL_TEXTURE_CUBE_MAP_POSITIVE_Y, GL_TEXTURE_CUBE_MAP_NEGATIVE_Y, GL_TEXTURE_CUBE_MAP_POSITIVE_Z, or GL_TEXTURE_CUBE_MAP_NEGATIVE_Z. no random targets allowed bestie 💅
• level — specifies the level-of-detail number. level 0 is the base image level. level n is the *n*th mipmap reduction image. literally the mipmap hierarchy, iykyk 🦋
• internalformat — specifies the internal format of the texture. must be one of these symbolic constants: GL_COMPRESSED_RED, GL_COMPRESSED_RG, GL_COMPRESSED_RGB, GL_COMPRESSED_RGBA. GL_COMPRESSED_SRGB, GL_COMPRESSED_SRGB_ALPHA. GL_DEPTH_COMPONENT, GL_DEPTH_COMPONENT16, GL_DEPTH_COMPONENT24, GL_DEPTH_COMPONENT32, GL_STENCIL_INDEX8, GL_RED, GL_RG, GL_RGB, GL_R3_G3_B2, GL_RGB4, GL_RGB5, GL_RGB8, GL_RGB10, GL_RGB12, GL_RGB16, GL_RGBA, GL_RGBA2, GL_RGBA4, GL_RGB5_A1, GL_RGBA8, GL_RGB10_A2, GL_RGBA12, GL_RGBA16, GL_SRGB, GL_SRGB8, GL_SRGB_ALPHA, or GL_SRGB8_ALPHA8. that's a lot of options, but you got this 🫶
• x, y — specify the window coordinates of the lower left corner of the rectangular region of pixels to be copied. think of it as the glow-up starting point ✨
• width — specifies the width of the texture image.
• height — specifies the height of the texture image.
• border — must be 0. literally just 0, no exceptions bestie 💀

🌸 DESCRIPTION 🌸

glCopyTexImage2D defines a two-dimensional texture image, or cube-map texture image with pixels from the current GL_READ_BUFFER.

the screen-aligned pixel rectangle with lower left corner at (x, y) and with a width of width and a height of height defines the texture array at the mipmap level specified by level. internalformat specifies the internal format of the texture array.

the pixels in the rectangle are processed exactly as if glReadPixels() had been called, but the process stops just before final conversion. at this point all pixel component values are clamped to the range 0 1 and then converted to the texture's internal format for storage in the texel array. it's giving "almost there but not quite" energy 😭

pixel ordering is such that lower x and y screen coordinates correspond to lower s and t texture coordinates.

if any of the pixels within the specified rectangle of the current GL_READ_BUFFER are outside the window associated with the current rendering context, then the values obtained for those pixels are undefined. so like, don't do that, it's not the vibe 🙈

when internalformat is one of the sRGB types, the GL does not automatically convert the source pixels to the sRGB color space. in this case, the glPixelMap function can be used to accomplish the conversion. noted bestie, don't forget it 🎀

💖 NOTES 💖

• 1, 2, 3, and 4 are not accepted values for internalformat. periodt.
• an image with height or width of 0 indicates a NULL texture.
• GL_STENCIL_INDEX8 is accepted for internalformat only if the GL version is 4.4 or higher. so check your version first, no cap.

🔥 ERRORS 🔥

• GL_INVALID_ENUM is generated if target is not GL_TEXTURE_2D, GL_TEXTURE_CUBE_MAP_POSITIVE_X, GL_TEXTURE_CUBE_MAP_NEGATIVE_X, GL_TEXTURE_CUBE_MAP_POSITIVE_Y, GL_TEXTURE_CUBE_MAP_NEGATIVE_Y, GL_TEXTURE_CUBE_MAP_POSITIVE_Z, or GL_TEXTURE_CUBE_MAP_NEGATIVE_Z.
• 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 width is less than 0 or greater than GL_MAX_TEXTURE_SIZE.
• GL_INVALID_VALUE is generated if border is not 0.
• GL_INVALID_VALUE is generated if internalformat is not an accepted format.
• GL_INVALID_OPERATION is generated if internalformat is GL_DEPTH_COMPONENT, GL_DEPTH_COMPONENT16, GL_DEPTH_COMPONENT24, or GL_DEPTH_COMPONENT32 and there is no depth buffer. like, you can't copy depth if there's no depth, obviously 💀

👑 ASSOCIATED GETS 👑

glGetTexImage() — the one and only, bestie 👑

🌈 VERSION SUPPORT 🌈

okay so here's the version support tea — this function is literally supported in every OpenGL version from 2.0 to 4.5, and the table is giving organized queen energy:

┌──────────────────┬───────────────────────────────────────────────────────────────────────┐
│                  │                OpenGL Version                                         │
├──────────────────┼─────┬─────┬─────┬─────┬─────┬─────┬─────┬─────┬─────┬─────┬─────┬─────┤
│ Function         │ 2.0 │ 2.1 │ 3.0 │ 3.1 │ 3.2 │ 3.3 │ 4.0 │ 4.1 │ 4.2 │ 4.3 │ 4.4 │ 4.5 │
│ /                │     │     │     │     │     │     │     │     │     │     │     │     │
│ Feature          │     │     │     │     │     │     │     │     │     │     │     │     │
│ Name             │     │     │     │     │     │     │     │     │     │     │     │     │
├──────────────────┼─────┼─────┼─────┼─────┼─────┼─────┼─────┼─────┼─────┼─────┼─────┼─────┤
│ glCopyTexImage2D │  ✔  │  ✔  │  ✔  │  ✔  │  ✔  │  ✔  │  ✔  │  ✔  │  ✔  │  ✔  │  ✔  │  ✔  │
└──────────────────┴─────┴─────┴─────┴─────┴─────┴─────┴─────┴─────┴─────┴─────┴─────┴─────┘

🦋 SEE ALSO 🦋

• glCopyTexImage1D()
• glCopyTexSubImage1D()
• glCopyTexSubImage2D()
• glPixelStore()
• glTexImage1D()
• glTexImage2D()
• glTexSubImage1D()
• glTexSubImage2D()
• glTexParameter()

💜 COPYRIGHT 💜

Copyright © 1991-2006 Silicon Graphics, Inc. Copyright © 2012-2014 Khronos Group. This document is licensed under the SGI Free Software B License. For details, see http://oss.sgi.com/projects/FreeB/.

🍓 COPYRIGHT 🍓

Copyright © 2013-2014 Khronos Group

---

and that's the whole page bestie 💅 this tea is from [FIXME: source] and it's dated 08/09/2021, giving full GLCOPYTEXIMAGE2D(3G) main character energy fr fr ✨🫶