GLBEGINTRANSFORMFEED(3G)

✨ NAME ✨

okay bestie, welcome to the GLBEGINTRANSFORMFEED(3G) page — yes, the header has a little [FIXME: manual] placeholder, but the manual name is GLBEGINTRANSFORMFEED(3G). This one is all about glBeginTransformFeedback and its whole “start transform feedback operation” moment. Periodt. 💅

🧾 C SPECIFICATION 🧾

Here are the exact signatures, no cap:

void glBeginTransformFeedback(GLenum primitiveMode);

void glEndTransformFeedback(void);

🎀 PARAMETERS FOR GLBEGINTRANSFORMFEEDBACK 🎀

• primitiveMode — specify the output type of the primitives that will be recorded into the buffer objects that are bound for transform feedback. That’s the whole assignment, bestie. 🫶

💖 DESCRIPTION 💖

Transform feedback mode captures the values of varying variables written by the vertex shader — or, if it’s active, the geometry shader. It’s giving “record the shader tea into buffers” energy. ✨

Transform feedback is said to be active after a call to glBeginTransformFeedback until a subsequent call to glEndTransformFeedback. Transform feedback commands must be paired — so like, do not leave your begin hanging, bestie. 😭

If no geometry shader is present, while transform feedback is active the mode parameter to glDrawArrays() must match those specified in this table’s info. Here’s the match-up in cute-list form:

• Transform feedback primitiveMode: GL_POINTS → allowed render primitive modes: GL_POINTS
• Transform feedback primitiveMode: GL_LINES → allowed render primitive modes: GL_LINES, GL_LINE_LOOP, GL_LINE_STRIP, GL_LINES_ADJACENCY, GL_LINE_STRIP_ADJACENCY
• Transform feedback primitiveMode: GL_TRIANGLES → allowed render primitive modes: GL_TRIANGLES, GL_TRIANGLE_STRIP, GL_TRIANGLE_FAN, GL_TRIANGLES_ADJACENCY, GL_TRIANGLE_STRIP_ADJACENCY

If a geometry shader is present, the output primitive type from the geometry shader must match those provided in this table’s info. That one goes like:

• Transform feedback primitiveMode: GL_POINTS → allowed geometry shader output primitive type: points
• Transform feedback primitiveMode: GL_LINES → allowed geometry shader output primitive type: line_strip
• Transform feedback primitiveMode: GL_TRIANGLES → allowed geometry shader output primitive type: triangle_strip

🦋 NOTES 🦋

Geometry shaders, and the GL_TRIANGLES_ADJACENCY, GL_TRIANGLE_STRIP_ADJACENCY, GL_LINES_ADJACENCY and GL_LINE_STRIP_ADJACENCY primitive modes are available only if the GL version is 3.2 or greater. So if you’re on an older vibe, those ones are a no-go. 💀

💀 ERRORS 💀

• GL_INVALID_OPERATION is generated if glBeginTransformFeedback is executed while transform feedback is active.
• GL_INVALID_OPERATION is generated if glEndTransformFeedback is executed while transform feedback is not active.
• GL_INVALID_OPERATION is generated by glDrawArrays() if no geometry shader is present, transform feedback is active and mode is not one of the allowed modes.
• GL_INVALID_OPERATION is generated by glDrawArrays() if a geometry shader is present, transform feedback is active and the output primitive type of the geometry shader does not match the transform feedback primitiveMode.
• GL_INVALID_OPERATION is generated by glBeginTransformFeedback if any binding point used in transform feedback mode does not have a buffer object bound.
• GL_INVALID_OPERATION is generated by glBeginTransformFeedback if no binding points would be used, either because no program object is active or because the active program object has specified no varying variables to record.

🔥 VERSION SUPPORT 🔥

okay so here’s the version tea. The table columns are OpenGL Version: 2.0, 2.1, 3.0, 3.1, 3.2, 3.3, 4.0, 4.1, 4.2, 4.3, 4.4, 4.5. The rows are Function / Feature Name:

• glBeginTransformFeedback — 2.0: -, 2.1: -, 3.0: ✔, 3.1: ✔, 3.2: ✔, 3.3: ✔, 4.0: ✔, 4.1: ✔, 4.2: ✔, 4.3: ✔, 4.4: ✔, 4.5: ✔
• glEndTransformFeedback — 2.0: -, 2.1: -, 3.0: ✔, 3.1: ✔, 3.2: ✔, 3.3: ✔, 4.0: ✔, 4.1: ✔, 4.2: ✔, 4.3: ✔, 4.4: ✔, 4.5: ✔

🌈 SEE ALSO 🌈

okay so the SEE ALSO section on this page is literally empty — no cross-references listed, bestie. It’s giving minimalist 😭.

📜 COPYRIGHT 📜

Copyright © 2010-2014 Khronos Group. This material may be distributed subject to the terms and conditions set forth in the Open Publication License, v 1.0, 8 June 1999. http://opencontent.org/openpub/.

📜 COPYRIGHT (again, bestie) 📜

Copyright © 2010-2014 Khronos Group

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okay bye bestie 💖 this page’s source/version situation is [FIXME: source], dated 08/09/2021, and the manual is GLBEGINTRANSFORMFEED(3G). Slay.