Speed up Color.random() via bit math

arcade/types.py

@@ -39,6 +39,15 @@
 MAX_UINT24 = 0xFFFFFF
 MAX_UINT32 = 0xFFFFFFFF
 
+MASK_RGBA_R = 0xFF000000
+MASK_RGBA_G = 0x00FF0000
+MASK_RGBA_B = 0x0000FF00
+MASK_RGBA_A = 0x000000FF
+
+MASK_RGB_R = 0xFF0000
+MASK_RGB_G = 0x00FF00
+MASK_RGB_B = 0x0000FF
+
 ChannelType = TypeVar('ChannelType')
 
 RGB = Tuple[ChannelType, ChannelType, ChannelType]
@@ -408,14 +417,15 @@ def random(
         :param b: Fixed value for blue channel
         :param a: Fixed value for alpha channel
         """
+        rand = random.randint(0, MAX_UINT32)
         if r is None:
-            r = random.randint(0, 255)
+            r = (rand & MASK_RGBA_R) >> 24
         if g is None:
-            g = random.randint(0, 255)
+            g = (rand & MASK_RGBA_G) >> 16
         if b is None:
-            b = random.randint(0, 255)
+            b = (rand & MASK_RGBA_B) >> 8
         if a is None:
-            a = random.randint(0, 255)
+            a = (rand & MASK_RGBA_A)
 
         return cls(r, g, b, a)
 

tests/unit/color/test_color_type.py

@@ -206,7 +206,14 @@ def test_deepcopy_color_inheritance():
 
 @pytest.fixture
 def randint_is_constant(monkeypatch):
-    monkeypatch.setattr('random.randint', Mock(return_value=RANDINT_RETURN_RESULT))
+    """
+    Replace the randomized color uint32 with a known signal value.
+
+    Since the color randomization masks out channels, we use a known
+    repeated value (128, or 0x80 in hex) to represent a channel fetched
+    from random rather than taken from user input.
+    """
+    monkeypatch.setattr('random.randint', Mock(return_value=0x80808080))
 
 
 def test_color_random(randint_is_constant):