Manpages - rtcSetGeometryBoundsFunction.3embree3

  rtcSetGeometryBoundsFunction - sets a callback to query the
    bounding box of user-defined primitives

  #include <embree3/rtcore.h>

  struct RTCBoundsFunctionArguments
  {
    void* geometryUserPtr;
    unsigned int primID;
    unsigned int timeStep;
    struct RTCBounds* bounds_o;
  };

  typedef void (*RTCBoundsFunction)(
    const struct RTCBoundsFunctionArguments* args
  );

  void rtcSetGeometryBoundsFunction(
    RTCGeometry geometry,
    RTCBoundsFunction bounds,
    void* userPtr
  );

The rtcSetGeometryBoundsFunction function registers a bounding box callback function (bounds argument) with payload (userPtr argument) for the specified user geometry (geometry argument).

Only a single callback function can be registered per geometry, and further invocations overwrite the previously set callback function. Passing NULL as function pointer disables the registered callback function.

The registered bounding box callback function is invoked to calculate axis-aligned bounding boxes of the primitives of the user-defined geometry during spatial acceleration structure construction. The bounding box callback of RTCBoundsFunction type is invoked with a pointer to a structure of type RTCBoundsFunctionArguments which contains various arguments, such as: the user data of the geometry (geometryUserPtr member), the ID of the primitive to calculate the bounds for (primID member), the time step at which to calculate the bounds (timeStep member), and a memory location to write the calculated bound to (bounds_o member).

In a typical usage scenario one would store a pointer to the internal representation of the user geometry object using rtcSetGeometryUserData. The callback function can then read that pointer from the geometryUserPtr field and calculate the proper bounding box for the requested primitive and time, and store that bounding box to the destination structure (bounds_o member).

On failure an error code is set that can be queried using rtcGetDeviceError.

[RTC_GEOMETRY_TYPE_USER]