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
25       increased in order to bound the curve in  the  worst  case  of  maximal
26       radii.
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28       One  also has to set the minWidthDistanceFactor in the RTCIntersectCon‐
29       text when tracing a ray.  This factor controls the target  radius  size
30       of a curve or point at some distance away of the ray origin.
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32       For  each  control point p with radius r of a curve or point primitive,
33       the primitive intersectors first calculate a target radius r' as:
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35              r' = length(p-ray_org) * minWidthDistanceFactor
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37       Typically the minWidthDistanceFactor is set  by  the  application  such
38       that  the  target  radius  projects  to the width of half a pixel (thus
39       primitive diameter is pixel sized).
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41       The target radius r' is then clamped against the minimal  bound  r  and
42       maximal bound maxRadiusScale*r to obtain the final radius r'':
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44              r'' = max(r, min(r', maxRadiusScale*r))
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46       Thus  curves  or  points close to the camera are rendered with a normal
47       radii r, and curves or points far from the camera are not enlarged  too
48       much, as this would be very expensive to render.
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50       When  rtcSetGeometryMaxRadiusScale  function is not invoked for a curve
51       or point geometry (or if the maximal scaling factor  is  set  to  1.0),
52       then the curve or point geometry renders normally, with radii not modi‐
53       fied by the min-width feature.
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55   EXIT STATUS
56       On failure an error code is set that can  be  queried  using  rtcGetDe‐
57       viceError.
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59   SEE ALSO
60       [rtcInitIntersectContext]
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64                                               rtcSetGeometryMaxRadiusScale(3)