Add generate_polygon, rename Rect -> AxisAlignedBB

geom/demos/aabb.py

@@ -1,5 +1,5 @@
 from pygame import draw
-from ..geom import Rect
+from ..geom import AxisAlignedBB
 from .. import WIDTH, HEIGHT, get_cursor_pos
 from ..colors import *
 from ..math import *
@@ -10,13 +10,13 @@ class AABBDistance:
     title = "AABB Distance"
 
     def render(self, surface):
-        rect_a = Rect(
+        rect_a = AxisAlignedBB(
             -(WIDTH / 8),
             -(HEIGHT / 8),
             WIDTH / 4,
             HEIGHT / 4,
         )
-        rect_b = Rect(
+        rect_b = AxisAlignedBB(
             *get_cursor_pos(),
             WIDTH / 5,
             HEIGHT / 5
@@ -52,7 +52,7 @@ class PointAABBDistance:
     title = "Point-AABB Distance"
 
     def render(self, surface):
-        rect_a = Rect(
+        rect_a = AxisAlignedBB(
             -(WIDTH / 8),
             -(HEIGHT / 8),
             WIDTH / 4,

geom/demos/sat.py

@@ -1,4 +1,4 @@
-from ..geom import Rect, Polygon
+from ..geom import Polygon, generate_polygon
 from .. import WIDTH, HEIGHT, get_cursor_pos, get_inputs
 from ..colors import *
 from ..math import *
@@ -10,12 +10,7 @@ class SeparatingAxisTheorem:
     title = "Separating Axis Theorem"
 
     def __init__(self):
-        self.shape1 = Polygon(0, 0, [
-            (0, 60),
-            (60, 0),
-            (0, -60),
-            (-60, 0)
-        ])
+        self.shape1 = generate_polygon(0, 0, sides=4, radius=60)
 
         self.shape2 = Polygon(*get_cursor_pos(), [
             (60, 60),
@@ -83,7 +78,8 @@ class SeparatingAxisTheorem:
             overlap = max(min2 - max1, min1 - max2)
             overlaps.append(overlap)
 
-            self.draw_axis(surface, normal, overlap < 0, min1, max1, min2, max2)
+            self.draw_axis(surface, normal, overlap < 0,
+                           min1, max1, min2, max2)
 
         colliding = all(overlap < 0 for overlap in overlaps)
         if colliding:

geom/geom.py

@@ -1,9 +1,10 @@
 from .math import *
 from .draw import *
 import numpy as np
+from math import pi, sin, cos
 
 
-class Rect:
+class AxisAlignedBB:
 
     def __init__(self, x, y, width, height):
         self.x = x
@@ -24,8 +25,8 @@ class Rect:
         self.halfwidth = self.width / 2
         self.halfheight = self.height / 2
 
-        self.cx = self.x + self.width / 2
-        self.cy = self.y + self.height / 2
+        self.cx = self.x + self.halfwidth
+        self.cy = self.y + self.halfheight
 
         self.vertices = [
             (self.x, self.y),
@@ -57,14 +58,14 @@ class Rect:
 
 class Polygon:
 
-    def __init__(self, x, y, vertices, origin_x=0, origin_y=0, rotation=0):
+    def __init__(self, x, y, vertices, rotation=0, origin_x=0, origin_y=0):
         self.x = x
         self.y = y
         self.vertices = vertices
+        self.rotation = rotation
         self.length = len(vertices)
         self.origin_x = origin_x
         self.origin_y = origin_y
-        self.rotation = rotation
         self.update_transformation()
         self.update()
 
@@ -127,3 +128,13 @@ class Polygon:
     def draw(self, surface, colour, width):
         polygon(surface, colour, self.translated_vertices, width)
         pixel(surface, colour, self.x, self.y)
+
+
+def generate_polygon(x, y, rotation=0, sides=3, radius=15):
+    theta = (2 * pi) / sides
+    return Polygon(x, y, [
+        scale(cos((2 * pi) - i * theta),
+              sin((2 * pi) - i * theta),
+              radius)
+        for i in range(sides)
+    ], rotation)