RTC_GEOMETRY_TYPE_USER - Online Linux Manual Page

Section : 3
Updated :
Source :
Note : Embree Ray Tracing Kernels 3

NAME

RTC_GEOMETRY_TYPE_USER − user geometry type

SYNOPSIS

#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.

EXIT STATUS

On failure NULL

is returned and an error code is set that can be queried using

rtcGetDeviceError