1rtcIntersect1(3)         Embree Ray Tracing Kernels 3         rtcIntersect1(3)
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3
4
5   NAME
6              rtcIntersect1 - finds the closest hit for a single ray
7
8   SYNOPSIS
9              #include <embree3/rtcore.h>
10
11              void rtcIntersect1(
12                RTCScene scene,
13                struct RTCIntersectContext* context,
14                struct RTCRayHit* rayhit
15              );
16
17   DESCRIPTION
18       The  rtcIntersect1  function finds the closest hit of a single ray with
19       the scene (scene argument).  The  provided  ray/hit  structure  (rayhit
20       argument) contains the ray to intersect and some hit output fields that
21       are filled when a hit is found.
22
23       The user has to initialize the ray origin (org ray member), ray  direc‐
24       tion  (dir  ray member), ray segment (tnear, tfar ray members), and set
25       the ray flags to 0 (flags ray member).  If the  scene  contains  motion
26       blur  geometries,  also the ray time (time ray member) must be initial‐
27       ized to a value in the range [0, 1].  If ray masks are enabled at  com‐
28       pile  time, the ray mask (mask ray member) must be initialized as well.
29       The ray segment has to be in the range [0, ∞], thus ranges  that  start
30       behind  the ray origin are not valid, but ranges can reach to infinity.
31       See Section [RTCRay] for the ray layout description.
32
33       The geometry ID (geomID hit member) of the hit data must be initialized
34       to RTC_INVALID_GEOMETRY_ID (-1).
35
36       Further,  an  intersection  context  for the ray query function must be
37       created and initialized (see rtcInitIntersectContext).
38
39       When no intersection is found, the ray/hit data is not  updated.   When
40       an  intersection  is  found,  the hit distance is written into the tfar
41       member of the ray and all hit data is set, such as unnormalized  geome‐
42       try normal in object space (Ng hit member), local hit coordinates (u, v
43       hit member), instance ID stack (instID hit member), geometry ID (geomID
44       hit  member),  and  primitive  ID  (primID  hit  member).   See Section
45       [RTCHit] for the hit layout description.
46
47       If the  instance  ID  stack  has  a  prefix  of  values  not  equal  to
48       RTC_INVALID_GEOMETRY_ID,  the  instance ID on each level corresponds to
49       the geometry ID of the hit instance  of  the  higher-level  scene,  the
50       geometry  ID  corresponds  to the hit geometry inside the hit instanced
51       scene, and the primitive ID corresponds to the n-th primitive  of  that
52       geometry.
53
54       If  level  0  of  the  instance ID stack is equal to RTC_INVALID_GEOME‐
55       TRY_ID, the geometry ID corresponds to  the  hit  geometry  inside  the
56       top-level scene, and the primitive ID corresponds to the n-th primitive
57       of that geometry.
58
59       The implementation makes no guarantees that primitives whose  hit  dis‐
60       tance is exactly at (or very close to) tnear or tfar are hit or missed.
61       If you want to exclude intersections at  tnear  just  pass  a  slightly
62       enlarged tnear, and if you want to include intersections at tfar pass a
63       slightly enlarged tfar.
64
65       The ray/hit structure must be aligned to 16 bytes.
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67   EXIT STATUS
68       For performance reasons this function does not  do  any  error  checks,
69       thus will not set any error flags on failure.
70
71   SEE ALSO
72       [rtcOccluded1], [RTCRayHit], [RTCRay], [RTCHit]
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76                                                              rtcIntersect1(3)