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|RTC_GEOMETRY_TYPE_USER(3)||Embree Ray Tracing Kernels 3||RTC_GEOMETRY_TYPE_USER(3)|
RTC_GEOMETRY_TYPE_USER - user geometry type
#include <embree3/rtcore.h> RTCGeometry geometry = rtcNewGeometry(device, RTC_GEOMETRY_TYPE_USER);
DESCRIPTION¶User-defined geometries contain a number of user-defined primitives, just like triangle meshes contain multiple triangles. The shape of the user-defined primitives is specified through registered callback functions, which enable extending Embree with arbitrary types of primitives.
User-defined geometries are created by passing RTC_GEOMETRY_TYPE_USER to the rtcNewGeometry function call. One has to set the number of primitives (see rtcSetGeometryUserPrimitiveCount), a user data pointer (see rtcSetGeometryUserData), a bounding function closure (see rtcSetGeometryBoundsFunction), as well as user-defined intersect (see rtcSetGeometryIntersectFunction) and occluded (see rtcSetGeometryOccludedFunction) callback functions. The bounding function is used to query the bounds of all time steps of a user primitive, while the intersect and occluded callback functions are called to intersect the primitive with a ray. The user data pointer is passed to each callback invocation and can be used to point to the application’s representation of the user geometry.
The creation of a user geometry typically looks the following:
RTCGeometry geometry = rtcNewGeometry(device, RTC_GEOMETRY_TYPE_USER); rtcSetGeometryUserPrimitiveCount(geometry, numPrimitives); rtcSetGeometryUserData(geometry, userGeometryRepresentation); rtcSetGeometryBoundsFunction(geometry, boundsFunction); rtcSetGeometryIntersectFunction(geometry, intersectFunction); rtcSetGeometryOccludedFunction(geometry, occludedFunction);
Please have a look at the rtcSetGeometryBoundsFunction, rtcSetGeometryIntersectFunction, and rtcSetGeometryOccludedFunction functions on the implementation of the callback functions.
Primitives of a user geometry are ignored during rendering when their bounds are empty, thus bounds have lower>upper in at least one dimension.
See tutorial [User Geometry] for an example of how to use the user-defined geometries.