From 349f4c27832ab6bd1e14a9c73acbdb5f4c6d4049 Mon Sep 17 00:00:00 2001
From: jgk <justin.g.kruger@gmail.com>
Date: Wed, 18 Aug 2021 18:52:09 +0200
Subject: [PATCH] Refactor dynamic camera code

---
 src/Dodge/Update.hs        |  1 +
 src/Dodge/Update/Camera.hs | 56 ++++++++++++++++++++++++++++----------
 2 files changed, 42 insertions(+), 15 deletions(-)

diff --git a/src/Dodge/Update.hs b/src/Dodge/Update.hs
index a79fed76f..3c0b66c02 100644
--- a/src/Dodge/Update.hs
+++ b/src/Dodge/Update.hs
@@ -88,6 +88,7 @@ functionalUpdate w = case _menuLayers w of
       where 
         (x,y) = cloudZoneOfPoint $ _clPos cl
 
+-- | Note the explict use of record syntax. Using lens creates a space leak.
 resetWorldEvents :: World -> World
 resetWorldEvents w = w {_worldEvents = id}
 
diff --git a/src/Dodge/Update/Camera.hs b/src/Dodge/Update/Camera.hs
index 34361578c..144a095a6 100644
--- a/src/Dodge/Update/Camera.hs
+++ b/src/Dodge/Update/Camera.hs
@@ -14,11 +14,15 @@ import Dodge.Config.KeyConfig
 import Dodge.Item.Attachment.Data
 import Geometry
 
+import qualified Data.List.NonEmpty as NEL
 import Control.Lens
+--import Control.Applicative
 import Data.Maybe
 import qualified Data.Set as S
 import qualified Data.IntMap.Strict as IM
 import qualified SDL
+import Data.Monoid
+import Data.Semigroup
 {- Update the screen camera rotation and position, including any in rold scope/remote camera modifiers; 
 update where your avatar's view is from.  -}
 updateCamera :: World -> World
@@ -154,25 +158,47 @@ autoZoomCam w = over cameraZoom changeZoom w
     zoomOutSpeed = 15
     scZoom = fromMaybe 1 $ yourItem w ^? itAttachment . _Just . scopeZoom
 
+
 farWallDist :: Point2 -> World -> Float
-{-# INLINE farWallDist #-}
-farWallDist cpos w = min (halfWidth w / (horizontalMax+50) ) (halfHeight w / (verticalMax+50) )
+--{-# INLINE farWallDist #-}
+farWallDist cpos w = values'
+    --min (halfWidth w / (horizontalMax+50) ) (halfHeight w / (verticalMax+50) )
   where
-    horizontalMax = maximum $ map (h' (V2 1 0)) rRays ++ map (h' (V2 (-1) 0)   ) lRays
-    verticalMax   = maximum $ map (h' (V2 0 1)) tRays ++ map (h' (V2 0    (-1))) bRays
-    --h p = fromMaybe p $ collidePointIndirect cpos p $ wallsAlongLine cpos p w
-    --h p = fromMaybe p . collidePointIndirect cpos p $ _walls w
+    horizontalMax = maximum $ map (horSize . h . (+.+) cpos . rotateV camRot) hRays
+    verticalMax   = maximum $ map (verSize . h . (+.+) cpos . rotateV camRot) vRays
     wos = wallsOnScreen w
-    h p = fromMaybe p $ collidePointIndirect cpos p wos
-    h' x p = dotV (rotateV camRot x) (p -.- cpos)
+    rv = rotateV camRot (V2 1 0)
+    rh = rotateV camRot (V2 0 1)
+    horSize = abs . dotV rv . (-.- cpos)
+    verSize = abs . dotV rh . (-.- cpos)
     camRot = _cameraRot w
-    rRays = rotF [V2   maxViewDistance  y | y <- zs]
-    lRays = rotF [V2 (-maxViewDistance) y | y <- zs]
-    tRays = rotF [V2 y   maxViewDistance  | y <- zs]
-    bRays = rotF [V2 y (-maxViewDistance) | y <- zs]
-    rotF = map (h . (+.+) cpos . rotateV (_cameraRot w))
-    zs = takeWhile (< maxViewDistance) [-maxViewDistance,negate $ 0.75*maxViewDistance..]
-    maxViewDistance = 800
+    hRays = [V2 x y | y <- zs , x <- [-maxViewDistance,maxViewDistance]]
+    vRays = [V2 x y | x <- zs , y <- [-maxViewDistance,maxViewDistance]]
+    h p = fromMaybe p $ collidePointIndirect cpos p wos
+    zs = [-maxViewDistance,negate $ 0.75*maxViewDistance..maxViewDistance]
+    zs' = NEL.fromList [-maxViewDistance,negate $ 0.75*maxViewDistance..maxViewDistance]
+    hw = halfWidth w
+    hh = halfHeight w
+    d x = Min . (x /) . (+ 50) . fromMaybe maxViewDistance . fmap getMax . getAp
+    values' = getMin . uncurry (<>) $ bimap (d hw) (d hh) $ sconcat $ NEL.map vsAt zs'
+    --values = map (\x -> (valueAtWidth x, valueAtHeight x)) zs
+    viewDistAtHeight  = rotateV camRot . V2 maxViewDistance
+    viewDistAtWidth x = rotateV camRot $ V2 x maxViewDistance
+    vsAt x = (valueAtWidth x,valueAtHeight x)
+    valueAtHeight h  = cpiv (cpos +.+ x) <> cpiv (cpos -.- x)
+      where
+        x = viewDistAtHeight h
+    valueAtWidth h  = cpih (cpos +.+ x) <> cpih (cpos -.- x)
+      where
+        x = viewDistAtWidth h
+    cpiv p = Ap $ fmap (Max . horSize) $ collidePointIndirect cpos p wos
+    cpih p = Ap $ fmap (Max . verSize) $ collidePointIndirect cpos p wos
+
+zs :: [Float]
+zs = [-maxViewDistance,negate $ 0.75*maxViewDistance..maxViewDistance]
     
+maxViewDistance :: Float
+maxViewDistance = 800
+
 --dirRays :: Float -> [Point2]
 --dirRays dir = take 11 $ iterate (rotateV (0.5 * pi / 10)) $ rotateV (dir-pi*0.25) (600,0)