Refactor light sources

src/Dodge/LightSource/Update.hs

@@ -0,0 +1,24 @@
+module Dodge.LightSource.Update where
+import Dodge.Data.LightSource
+import Geometry
+import Control.Lens
+
+updateTempLightSource :: TLSUpdate -> TempLightSource -> Maybe TempLightSource
+updateTempLightSource tlsu = case tlsu of
+    DestroyTLS -> const Nothing
+    TimerTLS -> timerTLS
+    IntensityTLS ConstantIntensity -> updateTempLightSource TimerTLS
+    IntensityTLS (TLSFade startcol x) -> fadeTLS startcol x
+
+fadeTLS :: Point3 -> Int -> TempLightSource -> Maybe TempLightSource
+fadeTLS startcol x tls
+    | t < 1 = Nothing
+    | t < x = Just $ tls & tlsParam . lsCol .~ (1 / fromIntegral (x - t)) *.*.* startcol
+    | otherwise = Just $ tls & tlsParam . lsCol .~ startcol -- this is wasteful, should be set once at begining
+  where
+    t = _tlsTime tls
+    
+timerTLS :: TempLightSource -> Maybe TempLightSource
+timerTLS t 
+    | _tlsTime t <= 0 = Nothing
+    | otherwise       = Just $ t & tlsTime -~ 1