From 1cd60a951b2c2f83b927a6b6961cbd3206bf5316 Mon Sep 17 00:00:00 2001
From: "Juan J. Martinez" <jjm@usebox.net>
Date: Tue, 25 Apr 2023 22:18:54 +0100
Subject: Added "tracker" enemy

---
 src/Game/Entities/Common.hs  | 13 +++++++++++++
 src/Game/Entities/Tracker.hs | 26 ++++++++++++++++++++++++++
 2 files changed, 39 insertions(+)
 create mode 100644 src/Game/Entities/Tracker.hs

(limited to 'src/Game/Entities')

diff --git a/src/Game/Entities/Common.hs b/src/Game/Entities/Common.hs
index eb84400..8fa7fe3 100644
--- a/src/Game/Entities/Common.hs
+++ b/src/Game/Entities/Common.hs
@@ -3,6 +3,7 @@ module Game.Entities.Common
     frameLimit,
     collision,
     inLine,
+    facingLower,
     updateFrame,
     updateGravity,
     turn,
@@ -54,6 +55,18 @@ inLine playerRef otherHeight other = do
              || (other.dir == DirRight && player.x > other.x)
          )
 
+-- | Check if the entity is facing the player and it is in a lower plarform.
+facingLower :: IORef Entity -> Collision
+facingLower playerRef other = do
+  player <- readIORef playerRef
+  pure $
+    player.typ == TypePlayer
+      && player.gravity == gravityOff
+      && player.y < other.y
+      && ( (other.dir == DirLeft && player.x < other.x)
+             || (other.dir == DirRight && player.x > other.x)
+         )
+
 -- | Update frame animation for entities that have direction.
 updateFrame :: Bool -> Entity -> Entity
 updateFrame updated e
diff --git a/src/Game/Entities/Tracker.hs b/src/Game/Entities/Tracker.hs
new file mode 100644
index 0000000..ef7325f
--- /dev/null
+++ b/src/Game/Entities/Tracker.hs
@@ -0,0 +1,26 @@
+module Game.Entities.Tracker (mkTracker) where
+
+import Game.Entities.Const
+import Game.Entities.Runner
+import Game.Entities.Types
+import qualified Game.Sprites as S
+
+mkTracker :: S.SpriteSheet -> Int -> Int -> Dir -> Collision -> Collision -> IsBlocked -> IO Entity
+mkTracker sprites x y d playerCollision facingPlayerLower isBlocked = do
+  s <- S.get sprites "tracker"
+  runner <- mkRunner sprites x y d playerCollision isBlocked
+  pure runner {sprite = s, update = updateTracker runner.update facingPlayerLower isBlocked}
+
+updateTracker :: (Entity -> IO Entity) -> Collision -> IsBlocked -> Entity -> IO Entity
+updateTracker updateRunner facingPlayerLower isBlocked ent = do
+  e <- updateRunner ent
+  facing <- facingPlayerLower e
+  pure $
+    if facing && e.gravity == gravityOff && not (isBlocked (ent.x + 8) (ent.y - 1)) && isBlocked (ent.x + 8) ent.y
+      then
+        e
+          { gravity = gravityUp,
+            frame = jumpFrame,
+            actions = [ActionAddEffect ent.x (ent.y + 8) "dust"]
+          }
+      else e
-- 
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