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loop/src/Dodge/Item/Weapon/LaserPath.hs
T
2022-07-11 10:26:33 +01:00

58 lines
2.2 KiB
Haskell

module Dodge.Item.Weapon.LaserPath
( reflectLaserAlong
) where
import Dodge.Data
import Dodge.Base.Wall
--import Dodge.Creature.HandPos
import Dodge.WorldEvent
import Geometry
--import Data.Maybe
--import Data.List
import Data.Bifunctor
import Data.Tuple
--import Streaming
--import qualified Streaming.Prelude as S
-- this needs to be tested with both reflections and refractions
reflectLaserAlong :: Float -> Point2 -> Point2 -> World
-> (Maybe (Point2,Either Creature Wall),[Point2])
{-# INLINE reflectLaserAlong #-}
reflectLaserAlong phasev sp ep w = case thingHitFilt (const True) _wlUnshadowed sp ep w of
Just (p,Right wl)
| _wlReflect wl -> second (p:) $ reflectLaserAlong phasev
(p +.+ unitVectorAtAngle (reflDirWall sp p wl))
(p +.+ dist p ep *.* unitVectorAtAngle (reflDirWall sp p wl))
w
| wlIsSeeThrough wl -> second (p:) $ reflectLaserAlong phasev
(p +.+ normalizeV (refract phasev sp ep wl p))
(refract phasev sp ep wl p)
w
| otherwise -> (Just (p,Right wl), [p])
Just (p,obj) -> (Just (p,obj), [p])
Nothing -> (Nothing, [ep])
refract :: Float -> Point2 -> Point2 -> Wall -> Point2 -> Point2
{-# INLINE refract #-}
refract phasev x y wl p
| isEntering = p +.+ rotateV angleRef (normalDist wlNormal)
| otherwise = p +.+ rotateV angleRef' (normalDist wlNormal')
where
wlNormal = vNormal $ uncurry (-.-) $ swap (_wlLine wl)
wlNormal' = vNormal $ uncurry (-.-) (_wlLine wl)
normalDist wlnormal = magV (p -.- y) *.* normalizeV wlnormal
angleInc = piRange $ argV wlNormal - argV (x -.- y)
angleRef
| reflectExternal = angleInc
| otherwise = asin $ sin angleInc / phasev
piRange a'
| a' > pi = a' - 2 * pi
| a' > negate pi = a'
| otherwise = a' + 2 * pi
isEntering = not $ isLeftOf (x -.- y) (uncurry (-.-) (_wlLine wl))
angleInc' = piRange $ argV wlNormal' - argV (x -.- y)
angleRef'
| reflectInternal = angleInc'
| otherwise = asin $ phasev * sin angleInc'
reflectInternal = 1 < abs (phasev * sin angleInc')
reflectExternal = 1 < abs (sin angleInc / phasev)