Progressively reveal the map to the player

As the character walks around the map, progressively reveal the entities
on the map to them, using an algorithm based on well known
circle-rasterizing and line-rasterizing algorithms to calculate lines of
sight that are potentially obscured by walls.

3 files changed, 11 insertions, 2 deletions

diff --git a/src/Xanthous/Entities/Character.hs b/src/Xanthous/Entities/Character.hs
index faa9964a3833..e2ca874dddbc 100644
--- a/src/Xanthous/Entities/Character.hs
+++ b/src/Xanthous/Entities/Character.hs
@@ -14,6 +14,9 @@ data Character = Character
   deriving anyclass (CoArbitrary, Function)
   deriving Draw via (DrawCharacter "@" Character)
 
+instance Entity Character where
+  blocksVision _ = False
+
 instance Arbitrary Character where
   arbitrary = pure Character
 
diff --git a/src/Xanthous/Entities/Creature.hs b/src/Xanthous/Entities/Creature.hs
index 983772090ee2..5af24a8cd3eb 100644
--- a/src/Xanthous/Entities/Creature.hs
+++ b/src/Xanthous/Entities/Creature.hs
@@ -8,7 +8,7 @@ import Data.Word
 
 import Xanthous.Prelude
 import Xanthous.Entities.RawTypes hiding (Creature)
-import Xanthous.Entities (Draw(..))
+import Xanthous.Entities (Draw(..), Entity(..))
 
 data Creature = Creature
   { _creatureType :: CreatureType
@@ -17,6 +17,9 @@ data Creature = Creature
   deriving stock (Eq, Show, Generic)
 makeLenses ''Creature
 
+instance Entity Creature where
+  blocksVision _ = False
+
 instance Draw Creature where
   draw = draw .view (creatureType . char)
 
diff --git a/src/Xanthous/Entities/Environment.hs b/src/Xanthous/Entities/Environment.hs
index f5301f94adf2..90fa05315a57 100644
--- a/src/Xanthous/Entities/Environment.hs
+++ b/src/Xanthous/Entities/Environment.hs
@@ -7,7 +7,7 @@ import Test.QuickCheck
 import Brick (str)
 import Brick.Widgets.Border.Style (unicode)
 --------------------------------------------------------------------------------
-import Xanthous.Entities (Draw(..), entityIs)
+import Xanthous.Entities (Draw(..), entityIs, Entity(..))
 import Xanthous.Entities.Draw.Util
 import Xanthous.Data
 --------------------------------------------------------------------------------
@@ -16,6 +16,9 @@ data Wall = Wall
   deriving stock (Show, Eq, Ord, Generic, Enum)
   deriving anyclass (CoArbitrary, Function)
 
+instance Entity Wall where
+  blocksVision _ = True
+
 instance Arbitrary Wall where
   arbitrary = pure Wall