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Added hexapolar and spiral ray patterns

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TQ Hirsch
2022-10-08 00:25:51 +02:00
parent a84bade226
commit b13f10a880
1 changed files with 20 additions and 3 deletions
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23
lib/Petzval/Trace.hs
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@@ -8,6 +8,9 @@ module Petzval.Trace
, HitRecord(..) , HitRecord(..)
, TraceError(..) , TraceError(..)
, raytrace , raytrace
-- * Ray patterns
, hexapolarPattern
, spiralPattern
) where ) where
import Linear import Linear
@@ -46,14 +49,14 @@ createRay :: (RealFloat a, Mode a, Epsilon a)
=> Maybe a -- ^ The image plane position. If `Nothing`, the object is at infinity => Maybe a -- ^ The image plane position. If `Nothing`, the object is at infinity
-> Pupil a -- ^ The entrance pupil to aim at -> Pupil a -- ^ The entrance pupil to aim at
-> a -- ^ Field angle -> a -- ^ Field angle
-> (a,a) -- ^ Normalized pupil coordinates (in the range \([-1,1]\)) -> V2 a -- ^ Normalized pupil coordinates (in the range \([-1,1]\))
-> Ray a -> Ray a
createRay (Just objectPlane) Pupil{position=pz,radius=pr} h (px, py) = createRay (Just objectPlane) Pupil{position=pz,radius=pr} h (V2 px py) =
Ray source (normalize $ target ^-^ source) Ray source (normalize $ target ^-^ source)
where dz = pz - objectPlane where dz = pz - objectPlane
source = V3 0 (dz * tan h) objectPlane source = V3 0 (dz * tan h) objectPlane
target = V3 (px * pr) (py * pr) pz target = V3 (px * pr) (py * pr) pz
createRay Nothing Pupil{position=pz,radius=pr} h (px, py) = Ray source (normalize $ target ^-^ source) createRay Nothing Pupil{position=pz,radius=pr} h (V2 px py) = Ray source (normalize $ target ^-^ source)
where h' = (pi * (-abs h) / 180) -- field angle in rad where h' = (pi * (-abs h) / 180) -- field angle in rad
dy = (V3 0 (cos h') (-sin h')) `project` (V3 0 (py * pr) 0) dy = (V3 0 (cos h') (-sin h')) `project` (V3 0 (py * pr) 0)
dz = V3 0 (pz * tan h') (pz * cos h') dz = V3 0 (pz * tan h') (pz * cos h')
@@ -124,3 +127,17 @@ raytrace system ray = trace' 1 ray system
(fray, rest) <- trace' n2 (nray'&_pos._z -~ element ^. thickness) elements (fray, rest) <- trace' n2 (nray'&_pos._z -~ element ^. thickness) elements
return (fray & _pos._z +~ element ^. thickness, HitRecord { pos=(nray' ^. _pos), opl} : rest) return (fray & _pos._z +~ element ^. thickness, HitRecord { pos=(nray' ^. _pos), opl} : rest)
-- | Spiral pattern. This is somewhat more irregular than the hexapolar pattern. The argument is the number of points
spiralPattern :: Floating a => Int -> [V2 a]
spiralPattern n = map (point . fromIntegral) [0..n-1]
where npoints = fromIntegral n - 1
point n = let r = sqrt (n / npoints)
theta = 2.3999632297286531 * n
in r *^ V2 (sin theta) (cos theta)
-- | A hexapolar pattern. This is rather optimally distributed; the argument is the number of rings
hexapolarPattern :: Floating a => Integer -> [V2 a]
hexapolarPattern nRings = (V2 0 0) : ( mconcat . map ring $ [0..nRings-1])
where ring n = let point t = r *^ V2 (sin t) (cos t)
r = (fromIntegral n) / (fromIntegral nRings)
in map (point . (\x -> x / (fromIntegral) n * 3 * pi) . fromIntegral) [0 .. n-1]