Allow changing polygon sides in SAT demo

geom/demos/aabb.py

@@ -9,6 +9,9 @@ class AABBDistance:
 
     title = "AABB Distance"
 
+    def handle_key_down(self, key):
+        pass
+
     def render(self, surface):
         rect_a = AxisAlignedBB(
             -(WIDTH / 8),
@@ -51,6 +54,9 @@ class PointAABBDistance:
 
     title = "Point-AABB Distance"
 
+    def handle_key_down(self, key):
+        pass
+
     def render(self, surface):
         rect_a = AxisAlignedBB(
             -(WIDTH / 8),

geom/demos/sat.py

@@ -1,3 +1,4 @@
+import pygame
 from ..geom import Polygon, generate_polygon
 from .. import WIDTH, HEIGHT, get_cursor_pos, get_inputs
 from ..colors import *
@@ -12,12 +13,25 @@ class SeparatingAxisTheorem:
     def __init__(self):
         self.shape1 = generate_polygon(0, 0, sides=4, radius=60)
 
-        self.shape2 = Polygon(*get_cursor_pos(), [
-            (60, 60),
-            (60, -60),
-            (-60, -60),
-            (-60, 60)
-        ])
+        self.shape2 = None
+        self.shape2_sides = 4
+        self.shape2_radius = 60
+        self.generate_shape2()
+
+    def generate_shape2(self):
+        rotation = 45 if self.shape2 is None else self.shape2.rotation
+        self.shape2 = generate_polygon(*get_cursor_pos(),
+                                       rotation,
+                                       sides=self.shape2_sides,
+                                       radius=self.shape2_radius)
+
+    def handle_key_down(self, key):
+        if key == pygame.K_a:
+            self.shape2_sides = max(self.shape2_sides - 1, 3)
+            self.generate_shape2()
+        if key == pygame.K_d:
+            self.shape2_sides = min(self.shape2_sides + 1, 31)
+            self.generate_shape2()
 
     def handle_input(self):
         self.shape2.set_position(*get_cursor_pos())

geom/demos/vec_proj.py

@@ -7,6 +7,9 @@ class VecProj:
 
     title = "Vector Projection"
 
+    def handle_key_down(self, key):
+        pass
+
     def render(self, surface):
         x1 = -(WIDTH / 4)
         y1 = 100

geom/screen.py

@@ -17,6 +17,8 @@ class Screen:
 
     def handle_input(self):
         for event in pygame.event.get(pygame.KEYDOWN):
+            self.demos[self.demo].handle_key_down(event.key)
+
             if event.key == pygame.K_DOWN:
                 self.demo += 1
                 if self.demo >= len(self.demos):