Add animated tail effect

lordmauve · Dec 3, 2018 · 237f310 · 237f310
1 parent 8b74235
commit 237f310
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diff --git a/examples/basic/images/tail_hook.png b/examples/basic/images/tail_hook.png
diff --git a/examples/basic/images/tail_piece.png b/examples/basic/images/tail_piece.png
diff --git a/examples/basic/tail.py b/examples/basic/tail.py
@@ -0,0 +1,35 @@
+from math import sin, cos
+SEGMENT_SIZE = 50
+ANGLE = 2.5
+PHASE_STEP = 0.3
+WOBBLE_AMOUNT = 0.5
+SPEED = 4.0
+
+tail = [
+    Actor('tail_piece') for _ in range(10)
+] + [Actor('tail_hook')]
+
+
+WIDTH = 800
+HEIGHT = 800
+
+t = 0
+
+
+def draw():
+    screen.clear()
+    for a in tail[::2]:
+        a.draw()
+    for a in tail[1::2]:
+        a.draw()
+
+def update(dt):
+    global t
+    t += dt
+    x = WIDTH - SEGMENT_SIZE // 2
+    y = HEIGHT - SEGMENT_SIZE // 2
+    for seg, a in enumerate(tail):
+        a.pos = x, y
+        angle = ANGLE + WOBBLE_AMOUNT * sin(seg * PHASE_STEP + t * SPEED)
+        x += SEGMENT_SIZE * cos(angle)
+        y -= SEGMENT_SIZE * sin(angle)
diff --git a/source-vectors/tail.svg b/source-vectors/tail.svg