GLMULTIDRAWELEMENTS(3G)

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

💖 NAME 💖

ok so glMultiDrawElements — it renders multiple sets of primitives by, like, specifying indices of array data elements ✨ bestie this is the one that saves you a million function calls 🫶

this one lives in the 3G manual section, and it's giving main character OpenGL energy ngl 👑

🌸 C SPECIFICATION 🌸

void glMultiDrawElements(GLenum mode, const GLsizei * count,
                         GLenum type, const GLvoid * const * indices,
                         GLsizei drawcount);

copy it exactly, okay? every pointer and const matters 💅

🎀 PARAMETERS 🎀

  • mode — tells GL what kind of primitives to render. accepted values are GL_POINTS, GL_LINE_STRIP, GL_LINE_LOOP, GL_LINES, GL_LINE_STRIP_ADJACENCY, GL_LINES_ADJACENCY, GL_TRIANGLE_STRIP, GL_TRIANGLE_FAN, GL_TRIANGLES, GL_TRIANGLE_STRIP_ADJACENCY, GL_TRIANGLES_ADJACENCY and GL_PATCHES ✨ that's the whole guest list, no plus-ones.
  • count — points to an array of the elements counts. like, how many indices per batch, one entry per draw 👀
  • type — the type of the values in indices. has to be exactly one of GL_UNSIGNED_BYTE, GL_UNSIGNED_SHORT, or GL_UNSIGNED_INT. pick wrong and it's not gonna slay 😭
  • indices — a pointer to the location where the indices are stored 🗂️
  • drawcount — the size of the count and indices arrays. iykyk 🌈

🦋 DESCRIPTION 🦋

okay so glMultiDrawElements specifies multiple sets of geometric primitives with, like, very few subroutine calls. no cap 🔥

instead of calling a GL function to pass every single individual vertex, normal, texture coordinate, edge flag, or color — which is exhausting, literally — you can prespecify separate arrays of vertices, normals, and so on, and then use them to construct a sequence of primitives with a single call to glMultiDrawElements. one call. ONE. we love efficiency 💅✨

glMultiDrawElements is identical in operation to glDrawElements() except that drawcount separate lists of elements are specified. that's it, that's the whole difference, periodt 🎯

vertex attributes that are modified by glMultiDrawElements have an unspecified value after glMultiDrawElements returns. yeah, unspecified — don't come for me, that's what the spec says 🙈. attributes that aren't modified maintain their previous values though, so those ones are safe 🌸

🧚 NOTES 🧚

GL_LINE_STRIP_ADJACENCY, GL_LINES_ADJACENCY, GL_TRIANGLE_STRIP_ADJACENCY and GL_TRIANGLES_ADJACENCY are available only if the GL version is 3.2 or greater ⭐ like, don't try it on your 2.1 build and then act surprised, bestie 💀

💜 ERRORS 💜

  • GL_INVALID_ENUM is generated if mode is not an accepted value 🚫
  • GL_INVALID_VALUE is generated if drawcount is negative. negative draws are not a vibe, they're an error 😤
  • GL_INVALID_OPERATION is generated if a non-zero buffer object name is bound to an enabled array or the element array and the buffer object's data store is currently mapped 🫠
fr fr check your errors, the group chat does not want to debug your blank screen at 3am 😭

👑 VERSION SUPPORT 👑

like the table said, but make it a list because we're cute like that 🎀

  • Function / Feature Name: glMultiDrawElements
  • OpenGL Version support: ✔ 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 ate and left zero crumbs — all twelve versions, every single checkmark 💅✨

🌈 SEE ALSO 🌈

  • glDrawArrays()
  • glDrawRangeElements()

go read those too, they're the supporting cast and they're iconic in their own right 🫶

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 © 2010-2014 Khronos Group

and that's the whole page, bestie 🎀 source is [FIXME: source], dated 08/09/2021, and it's the GLMULTIDRAWELEMENTS(3G) page — mwah, go draw some triangles 💖💅✨

📦 where this page comes from