GLCOPYTEXIMAGE2D(3G)

💅 GLCOPYTEXIMAGE2D(3G) — copy pixels into a 2D texture image 💅

Okay bestie, you're on the GLCOPYTEXIMAGE2D(3G) page, aka the 3G manual, and it's literally all about copying pixels into a 2D texture image. Let's get into it 🫶✨

🎀 NAME 🎀

glCopyTexImage2D — copy pixels into a 2D texture image, no cap.

📟 C SPECIFICATION 📟

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

🌸 PARAMETERS 🌸

• target — specifies the target texture. Must be GL_TEXTURE_2D, periodt.
• level — specifies the level-of-detail number. Level 0 is the base image level. Level n is the *n*th mipmap reduction image. Mipmap hierarchy vibes ✨
• internalformat — specifies the internal format of the texture. Must be one of the following symbolic constants: GL_ALPHA, GL_ALPHA4, GL_ALPHA8, GL_ALPHA12, GL_ALPHA16, GL_LUMINANCE, GL_LUMINANCE4, GL_LUMINANCE8, GL_LUMINANCE12, GL_LUMINANCE16, GL_LUMINANCE_ALPHA, GL_LUMINANCE4_ALPHA4, GL_LUMINANCE6_ALPHA2, GL_LUMINANCE8_ALPHA8, GL_LUMINANCE12_ALPHA4, GL_LUMINANCE12_ALPHA12, GL_LUMINANCE16_ALPHA16, GL_INTENSITY, GL_INTENSITY4, GL_INTENSITY8, GL_INTENSITY12, GL_INTENSITY16, 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, or GL_RGBA16.
• x, y — specify the window coordinates of the lower left corner of the rectangular region of pixels to be copied. Cute little corner coordinates 💖
• width — specifies the width of the texture image. Must be 0 or 2n+2*border for some integer n.
• height — specifies the height of the texture image. Must be 0 or 2m+2*border for some integer m.
• border — specifies the width of the border. Must be either 0 or 1.

🦋 DESCRIPTION 🦋

glCopyTexImage2D defines a two-dimensional texture image with pixels from the current GL_READ_BUFFER. Iconic behavior, honestly.

The screen-aligned pixel rectangle with lower left corner at (x, y) and with a width of width+2*border and a height of height+2*border 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 glCopyPixels 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. That's the pipeline moment, bestie 🌈

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. That's the risky undefined zone, so watch yourself 💀

✨ NOTES ✨

• glCopyTexImage2D is available only if the GL version is 1.1 or greater.
• Texturing has no effect in color index mode.
• 1, 2, 3, and 4 are not accepted values for internalformat.
• An image with height or width of 0 indicates a NULL texture.
• When the GL_ARB_imaging extension is supported, the RGBA components read from the framebuffer may be processed by the imaging pipeline. See glTexImage1D for specific details. Not me double-checking the extension tea 👀

💀 ERRORS 💀

• GL_INVALID_ENUM is generated if target is not GL_TEXTURE_2D.
• GL_INVALID_VALUE is generated if level is less than 0.
• GL_INVALID_VALUE may be generated if level is greater than log2max, where max is the returned value of GL_MAX_TEXTURE_SIZE.
• GL_INVALID_VALUE is generated if width or height is less than 0, greater than 2+GL_MAX_TEXTURE_SIZE, or if width or height cannot be represented as 2k+2*border for some integer k.
• GL_INVALID_VALUE is generated if border is not 0 or 1.
• GL_INVALID_VALUE is generated if internalformat is not one of the allowable values.
• GL_INVALID_OPERATION is generated if glCopyTexImage2D is executed between the execution of glBegin and the corresponding execution of glEnd. Do not do that, bestie 😭

🔥 ASSOCIATED GETS 🔥

• glGetTexImage
• glIsEnabled with argument GL_TEXTURE_2D

🌈 SEE ALSO 🌈

• glCopyPixels(3G)
• glCopyTexImage1D(3G)
• glCopyTexSubImage1D(3G)
• glCopyTexSubImage2D(3G)
• glPixelStore(3G)
• glPixelTransfer(3G)
• glTexEnv(3G)
• glTexGen(3G)
• glTexImage1D(3G)
• glTexImage2D(3G)
• glTexSubImage1D(3G)
• glTexSubImage2D(3G)
• glTexParameter(3G)

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That's the whole GLCOPYTEXIMAGE2D(3G) page, bestie! The footer in this copy is just GLCOPYTEXIMAGE2D(3G) again, so there's no extra source/version/date line to report — that's all the footer tea there is. Go copy those pixels and slay 💖✨🎀