RTCSETGEOMETRYVERTEXATTRIBUTETOPOLOGY(3embree3)

💖 NAME 💖

rtcSetGeometryVertexAttributeTopology — bestie, this one binds a vertex attribute to a topology of the geometry. that's the whole vibe. 🎀

✨ SYNOPSIS ✨

#include <embree3/rtcore.h>

void rtcSetGeometryVertexAttributeTopology(
  RTCGeometry geometry,
  unsigned int vertexAttributeID,
  unsigned int topologyID
);

🦋 DESCRIPTION 🦋

okay so picture this: rtcSetGeometryVertexAttributeTopology takes a vertex attribute buffer slot (that's the vertexAttributeID argument, heyyy) and binds it to a topology (the topologyID argument) for the subdivision geometry you're working with (the geometry argument, obviously 💅).

now here's the tea ☕ — standard vertex buffers are always bound to the default topology (that's topology 0) and there is literally no way to bind them any differently. no cap. they're committed. meanwhile a vertex attribute buffer will always use whichever topology it's been bound to whenever it gets used in the rtcInterpolate and rtcInterpolateN calls. it's giving loyal. 🫶

so what even is a topology with ID i? great question bestie 💖 it's made up of two things:

1. a subdivision mode, which you set through rtcSetGeometrySubdivisionMode
2. the index buffer that's bound to the index buffer slot i

and the way that this index buffer can assign indices for each face of the subdivision geometry that are different to the indices of the default topology?? obsessed. 😭 these new indices can, for example, be used to introduce additional borders into the subdivision mesh so you can map multiple textures onto one single subdivision geometry. multiple textures. one geometry. iconic behaviour tbh. ✨🧚

💀 EXIT STATUS 💀

if it flops, an error code gets set, and you can go query it with rtcGetDeviceError. so like, don't just sit there wondering what went wrong — go ask. 🙈

👑 SEE ALSO 👑

• rtcSetGeometrySubdivisionMode
• rtcInterpolate
• rtcInterpolateN

and that's the page, babe 💅 this lil love letter to you came from the Embree Ray Tracing Kernels 3 manual, section 3embree3, and the page itself signs off as rtcSetGeo...teTopology(3) — yes it abbreviates its own name, it's got main character energy like that. mwah. 🎀✨