Manpages - rtcInitPointQueryContext.3embree3

  rtcInitPointQueryContext - initializes the context information (e.g.
    stack of (multilevel-)instance transformations) for point queries

  #include <embree3/rtcore.h>

  struct RTC_ALIGN(16) RTCPointQueryContext
  {
    // accumulated 4x4 column major matrices from world to instance space.
    float world2inst[RTC_MAX_INSTANCE_LEVEL_COUNT][16];
    
    // accumulated 4x4 column major matrices from instance to world space.
    float inst2world[RTC_MAX_INSTANCE_LEVEL_COUNT][16];

    // instance ids.
    unsigned int instID[RTC_MAX_INSTANCE_LEVEL_COUNT];
    
    // number of instances currently on the stack.
    unsigned int instStackSize;
  };

  void rtcInitPointQueryContext(
    struct RTCPointQueryContext* context
  );

A stack (RTCPointQueryContext type) which stores the IDs and instance transformations during a BVH traversal for a point query. The transformations are assumed to be affine transformations (3×3 matrix plus translation) and therefore the last column is ignored (see [RTC_GEOMETRY_TYPE_INSTANCE] for details).

The rtcInitPointContext function initializes the context to default values and should be called for initialization.

The context will be passed as an argument to the point query callback function (see [rtcSetGeometryPointQueryFunction]) and should be used to pass instance information down the instancing chain for user defined instancing (see tutorial [ClosestPoint] for a reference implementation of point queries with user defined instancing).

The context is an necessary argument to [rtcPointQuery] and Embree internally uses the topmost instance tranformation of the stack to transform the point query into instance space.

No error code is set by this function.

[rtcPointQuery], [rtcSetGeometryPointQueryFunction]