GLXCREATEGLXPIXMAP(3gl)

✨ GLXCREATEGLXPIXMAP ✨

okay bestie, welcome to the GLX corner of the manual, section 3G — yes we're doing the GLX one today, and honestly? it's giving "off-screen but make it iconic". 💅

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🎀 NAME 🎀

glXCreateGLXPixmap — create an off-screen GLX rendering area

like, a little secret canvas that isn't on your screen. no cap. 🦋

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🌸 C SPECIFICATION 🌸

GLXPixmap glXCreateGLXPixmap( Display *dpy,
                              XVisualInfo *vis,
                              Pixmap pixmap )

delim $$

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💖 PARAMETERS 💖

• dpy — the connection to the X server. your lil phone line to the X server, basically. 📞
• vis — the visual that defines the structure of the rendering area. and listen, this is a pointer to an XVisualInfo structure, not a visual ID and not a pointer to a Visual. read it again bestie, this trips people up every single time. 😭
• pixmap — the X pixmap that's gonna be used as the front left color buffer of the off-screen rendering area. it's the main character buffer. 👑

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🔥 DESCRIPTION 🔥

glXCreateGLXPixmap creates an off-screen rendering area and returns its XID. any GLX rendering context that was created with respect to vis can be used to render into this off-screen area. and to actually associate the rendering area with a GLX rendering context, you use glXMakeCurrent. that's the glue, periodt. ✨

the X pixmap identified by pixmap is used as the front left buffer of the resulting off-screen rendering area. all other buffers specified by vis — including color buffers other than the front left buffer — are created without externally visible names. anonymous buffers, they're lowkey mysterious like that. 🙈

GLX pixmaps with double-buffering are supported. however, glXSwapBuffers is ignored by these pixmaps. not deprecated, not an error, just… ignored. the swap does not happen, bestie. it's giving "we don't do that here". 💀

some implementations may not support GLX pixmaps with direct rendering contexts. so if it doesn't work, it might not be you. 🌈

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🧚 NOTES 🧚

XVisualInfo is defined in Xutil.h. it's a structure that includes visual, visualID, screen, and depth elements. four lil fields, huge responsibility. 🎀

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💀 ERRORS 💀

• BadMatch is generated if the depth of pixmap does not match the depth value reported by core X11 for vis, or if pixmap was not created with respect to the same screen as vis. mismatched depths = instant vibe check failure.
• BadValue is generated if vis is not a valid XVisualInfo pointer (for example, if a particular GLX implementation does not support this visual).
• BadPixmap is generated if pixmap is not a valid pixmap.
• BadAlloc is generated if the server cannot allocate the GLX pixmap. the server said "no thoughts, no memory". 😭

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🫶 SEE ALSO 🫶

• glXCreateContext
• glXIsDirect
• glXMakeCurrent

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ngl, if you're mixing vis types or screens, expect BadMatch to show up uninvited. it's always the depth. it's literally always the depth. 👑

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and that's the whole page, bestie — GLXCREATEGLXPIXMAP, from the GLX manual section 3G. go forth and render off-screen. slay. 💖✨🎀🦋🌸