Move towards removal of ssaTri, which was buggy

src/Dodge/Base.hs

@@ -193,9 +193,9 @@ newCrKey :: World -> Int
 newCrKey = IM.newKey .  _creatures
 {- | TODO: determine precisely what this does. -}
 reflectPointCreature :: Point2 -> Point2 -> Creature -> Maybe (Point2, Point2, Int)
-reflectPointCreature p1 p2 cr = case collidePointCirc p1 p2 (_crRad cr) (_crPos cr) of
+reflectPointCreature p1 p2 cr = case intersectCircSegFirst (_crPos cr) (_crRad cr) p1 p2 of
     Nothing -> Nothing
-    Just _ -> Just 
+    Just a -> Just 
         ( p1
         , errorNormalizeV 35 (ssaTriPoint p2 (_crPos cr) p1 (_crRad cr) -.- _crPos cr) 
             +.+ (_crPos cr -.- _crOldPos cr)
@@ -214,7 +214,7 @@ reflectCircCreature
     -> Point2   -- ^ End point
     -> Creature 
     -> Maybe (Point2, Point2, Int)
-reflectCircCreature rad p1 p2 cr = case collidePointCirc p1 p2 (rad + _crRad cr) (_crPos cr) of
+reflectCircCreature rad p1 p2 cr = case intersectCircSegFirst (_crPos cr) (rad + _crRad cr) p1 p2 of
     Nothing -> Nothing
     Just _ -> Just 
         ( p1
@@ -335,55 +335,45 @@ collidePointWallsNorm p1 p2 ws
   where 
     f (a,_) = magV (p1 -.- a)
 -- | Returns the first creature, if any, that a point intersects with.
-collidePointCreatures :: Point2 -> Point2 -> World -> Maybe Int
-collidePointCreatures p1 p2 w 
+collidePointCreatures :: Point2 -> Point2 -> IM.IntMap Creature -> Maybe Int
+collidePointCreatures p1 p2 crs
     = fmap fst 
     . safeMinimumOn snd
     . IM.toList 
-    . IM.mapMaybe (\x -> collidePointCirc' p1 p2 (_crRad x) (_crPos x)) 
-    $_creatures w
+    . IM.mapMaybe (\x -> fmap (dist p1) $ intersectCircSegFirst (_crPos x) (_crRad x) p1 p2) 
+    $ crs
 -- | As for 'collidePointCreatures', only increases the radius of creatures by a
 --fixed amount, thus collides a moving circle with creaures.
-collideCircCreatures :: Point2 -> Point2 -> Float -> World -> Maybe Int
-collideCircCreatures p1 p2 rad w 
-    = fmap fst 
-    . safeMinimumOn snd
-    . IM.toList 
-    . IM.mapMaybe (\x -> collidePointCirc' p1 p2 (rad + _crRad x) (_crPos x)) 
-    $ _creatures w
+collideCircCreatures :: Point2 -> Point2 -> Float -> IM.IntMap Creature -> Maybe Int
+collideCircCreatures p1 p2 rad = collidePointCreatures p1 p2 . fmap (crRad +~ rad)
+
 -- | Returns the first creature id, if any, that a point intersects with, gives point
 --in creature on line.
-collidePointCrsPoint :: Point2 -> Point2 -> World -> Maybe (Point2,Int)
-collidePointCrsPoint p1 p2 w 
+collidePointCrsPoint :: Point2 -> Point2 -> IM.IntMap Creature -> Maybe (Point2,Int)
+collidePointCrsPoint p1 p2 crs
     = fmap f 
-    . safeMinimumOn (snd . snd)
+    . safeMinimumOn (dist p1 . snd)
     . IM.toList 
-    . IM.mapMaybe (\x -> collidePointCirc'' p1 p2 (_crRad x) (_crPos x)) 
-    $ _creatures w
+    . IM.mapMaybe (\x -> intersectCircSegFirst (_crPos x) (_crRad x) p1 p2) 
+    $ crs
   where 
-    f (cID,(p,_)) = (p,cID)
+    f (cID,p) = (p,cID)
 {- | Finds the first creature hit on a line.
 Maybe evaluates the creature id and hit point. -}
-collideCircCrsPoint :: Point2 -> Point2 -> Float -> World -> Maybe (Point2,Int)
-collideCircCrsPoint p1 p2 rad w 
-    = fmap f 
-    . safeMinimumOn (snd . snd)
-    . IM.toList 
-    . IM.mapMaybe (\x -> collidePointCirc'' p1 p2 (rad + _crRad x) (_crPos x)) 
-    $ _creatures w
-  where 
-    f (cID,(p,_)) = (p,cID)
--- | Makes a creature not hittable.
-collidePointCrsWithoutPoint :: Int -> Point2 -> Point2 -> World -> Maybe (Point2,Int)
-collidePointCrsWithoutPoint cid p1 p2 w 
-    = fmap f 
-    . safeMinimumOn (snd . snd)
-    . IM.toList 
-    . IM.mapMaybe (\x -> collidePointCirc'' p1 p2 (_crRad x) (_crPos x)) 
-    . IM.delete cid 
-    $ _creatures w
-  where 
-    f (cID,(p,_)) = (p,cID)
+collideCircCrsPoint :: Point2 -> Point2 -> Float -> IM.IntMap Creature -> Maybe (Point2,Int)
+collideCircCrsPoint p1 p2 rad = collidePointCrsPoint p1 p2 . fmap (crRad +~ rad)
+
+---- | Makes a creature not hittable.
+--collidePointCrsWithoutPoint :: Int -> Point2 -> Point2 -> World -> Maybe (Point2,Int)
+--collidePointCrsWithoutPoint cid p1 p2 w 
+--    = fmap f 
+--    . safeMinimumOn (snd . snd)
+--    . IM.toList 
+--    . IM.mapMaybe (\x -> collidePointCirc'' p1 p2 (_crRad x) (_crPos x)) 
+--    . IM.delete cid 
+--    $ _creatures w
+--  where 
+--    f (cID,(p,_)) = (p,cID)
 {- | Test if a circle collides with any wall. 
  - Note no check on whether the wall is walkable. -}
 circOnSomeWall :: Point2 -> Float -> World -> Bool