Work on gibs and chasms

src/Dodge/Prop/Moving.hs

@@ -1,13 +1,37 @@
 module Dodge.Prop.Moving (
     fallSmallBounceDamage,
     fallSmallBounce,
+    updateDebrisChunk,
 ) where
 
+import Linear.Metric
+import Linear.V3
 import Dodge.Damage
 import Dodge.Base
 import Dodge.Data.World
 import Geometry
 import LensHelp
+import Control.Monad
+
+updateDebrisChunk :: World -> Debris -> (World, Maybe Debris)
+updateDebrisChunk w db = (w, mdb)
+  where
+    cdb' 
+        | norm sv < 0.5 && abs (sp ^. _z) < 0.5 = db
+        | otherwise = cdb
+    sv = db ^. dbVel
+    sp = _dbPos db
+    np = sp + sv
+    cdb = case collide3 sp np w of
+        (p,Nothing) -> db & dbPos .~ p
+            & dbVel -~ V3 0 0 1
+            & dbRot %~ dospin
+        (p,Just n) -> db & dbPos .~ p + (0.0001 * normalize n)
+            & dbVel .~ (0.7 * reflectInNormal n sv) - V3 0 0 1
+    dospin = (_dbSpin db *)
+    mdb = do
+        guard (np > -100)
+        return $ cdb'
 
 fallSmallBounceDamage :: Prop -> World -> World
 fallSmallBounceDamage pr w =