Improve eel movement

1 files changed, 41 insertions, 6 deletions

diff --git a/fish_types.py b/fish_types.py
index 63e082e..73b58c1 100644
--- a/fish_types.py
+++ b/fish_types.py
@@ -25,6 +25,8 @@ class Fish(object):
         self.tailAcceleration = C.Vector(self.tailAccelMag, 0)
         self.tailMoving = False
         self.tailMoveCount = 0
+        if not hasattr(self, 'theta_scale'):
+            self.theta_scale = 12
 
     @classmethod
     def by_type(cls, fish_type):
@@ -71,14 +73,14 @@ class Fish(object):
     def fix_direction(self):
         min_theta = -0.32
         max_theta = 0.32
-        if self.y < 0:
+        if self.y + self.height < 0:
             min_theta = 0
-        if self.y > 1:
+        if self.y > 2:
             max_theta = 0
             
         #theta = rand_in_range(min_theta, max_theta)
         theta = random.gauss(
-            (max_theta+min_theta)/2, (max_theta - min_theta)/12
+            (max_theta+min_theta)/2, (max_theta - min_theta)/self.theta_scale
         )
         self.tailAcceleration = C.Vector(self.tailAccelMag, 0).rot2d(theta)
 
@@ -86,6 +88,12 @@ class Fish(object):
         """May be overridden to provide multicolored fish."""
         return self.color
 
+    def alpha_at(self, x, y):
+        """Return an additional scale amount for clear parts.
+
+        This is overridden to have oddly shaped fish, such as the eel."""
+        return 1
+
 
 class Jellyfish(Fish):
     color = C.HSV(298/360, 89/100, 53/100).to_RGB()
@@ -174,6 +182,9 @@ class Whale(Fish):
     tailThreshold = 0.7
     tailDuration = 3
     tailAccelMag = 0.4
+    theta_scale = 20
+
+    y = 0
 
     white_x_min = 30
     white_x_width = 8
@@ -210,11 +221,34 @@ class Stingray(Fish):
 class Eel(Fish):
     color = C.HSV(109/360, 83/100, 35/100).to_RGB()
     drag = -0.09
-    width = 23
-    height = 1.5
+    width = 50
+    height = 2
     tailThreshold = 0.7
     tailDuration = 2
-    tailAccelMag = 0.4
+    tailAccelMag = 0.1
+
+    front_offset = 0
+    y = 0
+
+    def alpha_at(self, x, y):
+        rel_x = x - self.x
+        rel_y = y - self.y
+        eel_height = math.sin(
+                2 * math.pi * (rel_x + self.front_offset) / self.width
+            ) / 2 + 0.5
+        y_blend = abs(rel_y - eel_height)
+        if y_blend > 0.5:
+            return 0
+        return (1 - y_blend)
+
+    def update(self):
+        self.front_offset += abs(self.speed)
+        if self.front_offset > self.width:
+            self.front_offset = 0
+        return super(Eel, self).update()
+
+    def fix_direction(self):
+        pass
 
 
 class Shark(Fish):
@@ -225,6 +259,7 @@ class Shark(Fish):
     tailThreshold = 0.7
     tailDuration = 3
     tailAccelMag = 0.4
+    theta_scale = 20
 
 
 def rand_in_range(low, high):