rtcForwardOccluded1/Ex(3)

  NAME

    rtcForwardOccluded1/Ex - forwards a single ray to new scene
      from user geometry callback

  SYNOPSIS

    #include <embree4/rtcore.h>

    void rtcForwardOccluded1(
      const struct RTCOccludedFunctionNArguments* args,
      RTCScene scene,
      struct RTCRay* ray,
      unsigned int instID
    );

    void rtcForwardOccluded1Ex(
      const struct RTCOccludedFunctionNArguments* args,
      RTCScene scene,
      struct RTCRay* ray,
      unsigned int instID,
      unsigned int instPrimID
    );

  DESCRIPTION

The rtcForwardOccluded1 and rtcForwardOccluded1Ex functions forward the traversal of a transformed ray (ray argument) into a scene (scene argument) from a user geometry callback. The function can only get invoked from a user geometry callback for a ray traversal initiated with the rtcOccluded1 function. The callback arguments structure of the callback invokation has to get passed to the ray forwarding (args argument). The user geometry callback should instantly terminate after invoking the rtcForwardOccluded1/Ex function.

Only the ray origin and ray direction members of the ray argument are used for forwarding, all additional ray properties are inherited from the initial ray traversal invokation of rtcOccluded1.

The implementation of the rtcForwardOccluded1 function recursively continues the ray traversal into the specified scene and pushes the provided instance ID (instID argument) to the instance ID stack. Hit information is updated into the ray structure passed to the original rtcOccluded1 invokation.

This function can get used to implement user defined instancing using user geometries, e.g. by transforming the ray in a special way, and/or selecting between different scenes to instantiate.

For user defined instance arrays, the rtcForwardIntersect1Ex variant has an additional instPrimID argument which is pushed to the instance primitive ID stack. Instance primitive IDs identify which instance of an instance array was hit.

When using Embree on the CPU it is possible to recursively invoke rtcOccluded1 directly from a user geometry callback. However, when SYCL is used, recursively tracing rays is not directly supported, and the rtcForwardOccluded1/Ex function must be used.

The ray structure must be aligned to 16 bytes.

  EXIT STATUS

For performance reasons this function does not do any error checks, thus will not set any error flags on failure.

  SEE ALSO

[rtcOccluded1], [RTCRay]