1 files changed, 36 insertions, 0 deletions
diff --git a/src/gui/background_sprite.py b/src/gui/background_sprite.py
new file mode 100644
index 0000000..0579af8
--- /dev/null
+++ b/src/gui/background_sprite.py
@@ -0,0 +1,36 @@
+from random import randint
+
+import pygame
+from pygame.locals import *
+
+from simulation import Simulation
+
+class Sprite_Background(pygame.sprite.Sprite):
+    def __init__(self, simulation: type[Simulation]):
+        super().__init__()
+        self.simulation = simulation
+
+    def update(self, display_width, display_height):
+        self.image = pygame.Surface([display_width, display_height])
+
+        #TODO: put into its own functions drawBg() drawStars()
+        self.image.fill(self.get_color_for_height(self.simulation.rocket_altitude()))
+        
+        #draw stars, TODO: should be its own sprite and speed should actually matter
+        if self.simulation.rocket_altitude() > 30000:
+            for _ in range(100):
+                self.image.set_at((randint(0, display_width), randint(0, display_height)), (255, 255, 255))
+        
+        self.rect = self.image.get_rect()
+
+    def linear_gradient(self, start_color, end_color, length, value_at):
+        return [
+            int(start_color[j] + (float(value_at)/(length-1))*(end_color[j]-start_color[j]))
+            for j in range(3)
+        ]
+
+    def get_color_for_height(self, height: float) -> (int, int, int):
+        if height < 70000:
+            return self.linear_gradient((31,118,194), (0, 0, 0), 70000, int(height))
+        else:
+            return (0, 0, 0)
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