1rtcIntersect1(3)         Embree Ray Tracing Kernels 4         rtcIntersect1(3)
2
3
4
5   NAME
6              rtcIntersect1 - finds the closest hit for a single ray
7
8   SYNOPSIS
9              #include <embree4/rtcore.h>
10
11              void rtcIntersect1(
12                RTCScene scene,
13                struct RTCRayHit* rayhit
14                struct RTCIntersectArguments* args = NULL
15              );
16
17   DESCRIPTION
18       The  rtcIntersect1 function finds the closest hit of a single ray (ray‐
19       hit argument) with the scene (scene argument).   The  provided  ray/hit
20       structure contains the ray to intersect and some hit output fields that
21       are filled when a hit is found.  The passed optional  arguments  struct
22       (args  argument)  can  get  used  for  advanced  use cases, see section
23       [rtcInitIntersectArguments] for more details.
24
25       To trace a ray, the user has to initialize the ray origin (org ray mem‐
26       ber), ray direction (dir ray member), ray segment (tnear, tfar ray mem‐
27       bers), ray mask (mask ray member), and set the ray flags  to  0  (flags
28       ray  member).   The ray time (time ray member) must be initialized to a
29       value in the range $[0, 1].  The ray segment has to  be  in  the  range
30       [0, ∞], thus ranges that start behind the ray origin are not valid, but
31       ranges can reach to infinity.  See Section [RTCRay] for the ray  layout
32       description.
33
34       The geometry ID (geomID hit member) of the hit data must be initialized
35       to RTC_INVALID_GEOMETRY_ID (-1).
36
37       When no intersection is found, the ray/hit data is not  updated.   When
38       an  intersection  is  found,  the hit distance is written into the tfar
39       member of the ray and all hit data is set, such as unnormalized  geome‐
40       try normal in object space (Ng hit member), local hit coordinates (u, v
41       hit member), instance ID stack (instID hit member), geometry ID (geomID
42       hit  member),  and  primitive  ID  (primID  hit  member).   See Section
43       [RTCHit] for the hit layout description.
44
45       If the instance ID stack has a prefix of values not  equal  to  RTC_IN‐
46       VALID_GEOMETRY_ID, the instance ID on each level corresponds to the ge‐
47       ometry ID of the hit instance of the higher-level scene,  the  geometry
48       ID  corresponds to the hit geometry inside the hit instanced scene, and
49       the primitive ID corresponds to the n-th primitive of that geometry.
50
51       If level 0 of the instance ID  stack  is  equal  to  RTC_INVALID_GEOME‐
52       TRY_ID, the geometry ID corresponds to the hit geometry inside the top-
53       level scene, and the primitive ID corresponds to the n-th primitive  of
54       that geometry.
55
56       The  implementation  makes no guarantees that primitives whose hit dis‐
57       tance is exactly at (or very close to) tnear or tfar are hit or missed.
58       If  you want to exclude intersections at tnear just pass a slightly en‐
59       larged tnear, and if you want to include intersections at tfar  pass  a
60       slightly enlarged tfar.
61
62       The ray/hit structure must be aligned to 16 bytes.
63
64   EXIT STATUS
65       For  performance  reasons  this  function does not do any error checks,
66       thus will not set any error flags on failure.
67
68   SEE ALSO
69       [rtcOccluded1], [rtcIntersect4/8/16], [RTCRayHit], [rtcInitIntersectAr‐
70       guments]
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73
74                                                              rtcIntersect1(3)