1rtcSetGeometryMaxRadiusScaElmeb(r3e)e Ray Tracing KernretlcsSe3tGeometryMaxRadiusScale(3)
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5   NAME
6              rtcSetGeometryMaxRadiusScale - assigns a maximal curve radius scale factor for min-width feature
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8   SYNOPSIS
9              #include <embree3/rtcore.h>
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11              void rtcSetGeometryMaxRadiusScale(RTCGeometry geometry, float maxRadiusScale);
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13   DESCRIPTION
14       The  rtcSetMaxGeometryScale function specifies a maximal scaling factor
15       for curve radii used by the min-width feature.
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17       The min-width feature can increase the radius of curves and points,  in
18       order to reduce aliasing and improve render times.  The feature is dis‐
19       abled by default and has to  get  enabled  using  the  EMBREE_MIN_WIDTH
20       cmake option.
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22       To  use  the feature, one has to specify a maximal curve radius scaling
23       factor using the [rtcSetGeometryMaxRadiusScale] function.  This  factor
24       should be a small number (e.g. 4) as the constructed BVH bounds get in‐
25       creased in order to bound the curve in the worst case of maximal radii.
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27       One also has to set the minWidthDistanceFactor in the  RTCIntersectCon‐
28       text  when  tracing a ray.  This factor controls the target radius size
29       of a curve or point at some distance away of the ray origin.
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31       For each control point p with radius r of a curve or  point  primitive,
32       the primitive intersectors first calculate a target radius r’ as:
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34              r' = length(p-ray_org) * minWidthDistanceFactor
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36       Typically  the  minWidthDistanceFactor  is  set by the application such
37       that the target radius projects to the width  of  half  a  pixel  (thus
38       primitive diameter is pixel sized).
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40       The  target  radius  r’ is then clamped against the minimal bound r and
41       maximal bound maxRadiusScale*r to obtain the final radius r’’:
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43              r'' = max(r, min(r', maxRadiusScale*r))
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45       Thus curves or points close to the camera are rendered  with  a  normal
46       radii  r, and curves or points far from the camera are not enlarged too
47       much, as this would be very expensive to render.
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49       When rtcSetGeometryMaxRadiusScale function is not invoked for  a  curve
50       or  point  geometry  (or  if the maximal scaling factor is set to 1.0),
51       then the curve or point geometry renders normally, with radii not modi‐
52       fied by the min-width feature.
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54   EXIT STATUS
55       On  failure  an  error  code is set that can be queried using rtcGetDe‐
56       viceError.
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58   SEE ALSO
59       [rtcInitIntersectContext]
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63                                               rtcSetGeometryMaxRadiusScale(3)