use intermediate surface for trail effect, restore static to top layer

electric_sieve/ElectricSieve.py

@@ -66,6 +66,13 @@ class ElectricSieve(Game):
             self.initialize_gpio()
 
         self.velocity = Vector(0, 0)
+
+        # Create an intermediate surface to draw the triangles to and create a trail effect
+        self.trail_effect = Surface(self.get_display_surface().get_size(), pygame.SRCALPHA)
+
+        # Create a black background
+        self.background = Surface(self.get_display_surface().get_size())
+        self.background.fill((0, 0, 0))
             
         # Create game objects
         self.title = Title(self)
@@ -75,11 +82,6 @@ class ElectricSieve(Game):
         self.static = Static(self)
         self.land = Land(self)
 
-        # Create a purple background
-        self.background = Surface(self.display.screen.get_size())
-        # self.background.fill((255, 80, 190))
-        self.background.fill((0, 0, 0))
-
         # Start the title screen
         self.title.activate()
 
@@ -157,15 +159,36 @@ class ElectricSieve(Game):
         return rotated
 
     def update(self):
-        self.background.set_alpha(int((1 - self.acid.get_volume() * 1.75) * 255))
         self.title.update()
+
+        # Test if the level is being played
         if self.triangles.active:
-            self.display.screen.blit(self.background, (0, 0))
+
+            # Draw grid effect
             self.land.update()
-        self.static.update()
-        self.triangles.update()
+
+            # Set the background alpha low to create a trail effect on the triangles.
+            self.background.set_alpha(255 * 0.1)
+
+            # Draw the alpha background only to the trail effect surface. This will partially erase the previous drawings of the triangles.
+            self.trail_effect.blit(self.background, (0, 0))
+
+            # Draw triangles onto the trail effect surface, update position
+            self.triangles.update()
+
+            # Set alpha back to full for drawing the bottom layer background
+            self.background.set_alpha(255)
+            self.get_display_surface().blit(self.background, (0, 0))
+
+        # Draw the triangles to the screen, using the intermediate trail effect surface
+        self.get_display_surface().blit(self.trail_effect, (0, 0))
+
+        # Draw the sieve
         self.sieve.update()
 
+        # Draw the static
+        self.static.update()
+
 
 class Title(GameChild):
 
@@ -218,6 +241,7 @@ class Title(GameChild):
                 self.parent.sieve.activate()
                 self.parent.static.activate()
                 self.advance.play()
+                self.get_display_surface().blit(self.get_game().background, (0, 0))
 
     def activate(self):
         self.active = True
@@ -508,7 +532,7 @@ class Triangles(GameChild, list):
         GameChild.__init__(self, parent)
         self.music = Sound(self.get_resource("audio", "triangles"))
         self.deactivate()
-        self.display_surface = self.get_display_surface()
+        self.display_surface = self.get_game().trail_effect
         self.delegate = self.get_game().delegate
         self.booster = Shift(self, 1, "boost")
         self.hit = Sound(self.get_resource("audio", "hit"))

electric_sieve/land/Land.py

@@ -11,6 +11,7 @@ class Land(GameChild, Rect):
 
     def __init__(self, parent):
         GameChild.__init__(self, parent)
+        self.display_surface = self.get_game().background
         self.load_configuration()
         if not self.get_game().rotated:
             self.intermediate = pygame.Surface(self.get_display_surface().get_size())

electric_sieve/land/Plate.py

@@ -24,7 +24,7 @@ class Plate(GameChild, Surface):
         color = Color(0, 0, 0)
         for y in range(height):
             hue = abs(int(float(y) / (height) * 240) - 120)
-            color.hsva = hue, 100, 20, 100
+            color.hsva = hue, 100, 40, 100
             background.fill(color, (0, y, width, 1))
         self.background = background