RTCGETGEOMETRYFIRSTHALFEDGE(3)

✨ rtcGetGeometryFirstHalfEdge — Embree Ray Tracing Kernels 4 ✨

okay bestie, welcome to the rtcGetGeo...stHalfEdge(3) page, we're getting into the Embree Ray Tracing Kernels 4 lore today and honestly? it's giving geometry nerdery in the best way 💖

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🎀 NAME 🎀

rtcGetGeometryFirstHalfEdge — returns the first half edge of a face

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🦋 SYNOPSIS 🦋

#include <embree4/rtcore.h>

unsigned int rtcGetGeometryFirstHalfEdge(
  RTCGeometry geometry,
  unsigned int faceID
);

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🌸 DESCRIPTION 🌸

so the rtcGetGeometryFirstHalfEdge function hands you back the ID of the first half edge that belongs to the face you point at with the faceID argument. like, you ask "which face?" and it's all "here's the first edge of it, bestie 🫶".

for instance, in the example below, the first half edge of face f1 is e4.

heads up 💅 this function can only be used for subdivision geometries. no other geometry types, periodt.

and here's the cute part: since all topologies of a subdivision geometry share the same face buffer, this function does not depend on the topology ID. one face buffer, all the topologies, no drama ✨.

okay so picture this: f0 to f7 are 8 quadrilateral faces, each with 4 vertices. the edges e0 to e23 of these faces are shown with their orientation. for each face, the ID of the edges corresponds to the slots the face occupies in the index array of the geometry. e.g. since the indices of face f1 start at location 4 of the index array, the first edge is edge e4, the next edge e5, etc. the way the numbering just lines up like that? iconic, no cap 🧚

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💀 EXIT STATUS 💀

if it fails, an error code is set that you can query using rtcGetDeviceError. so if things go sideways, that's your 911 call 📞

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👑 SEE ALSO 👑

• [rtcGetGeometryFirstHalfEdge]
• [rtcGetGeometryFace]
• [rtcGetGeometryOppositeHalfEdge]
• [rtcGetGeometryNextHalfEdge]
• [rtcGetGeometryPreviousHalfEdge]

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and that's the whole page, bestie!! go forth and get those half edges 💖 this was rtcGetGeo...stHalfEdge(3) from the Embree Ray Tracing Kernels 4 era, and yeah, the whole thing is still serving main character energy. stay hydrated, read your manpages, slay 💅✨