feat(sim): geometry primitives and collision math

game/sim/geometry.py

@@ -0,0 +1,156 @@
+import math
+
+
+class Vec2:
+    __slots__ = ("x", "y")
+
+    def __init__(self, x=0.0, y=0.0):
+        self.x = float(x)
+        self.y = float(y)
+
+    def copy(self):
+        return Vec2(self.x, self.y)
+
+    def set(self, x, y):
+        self.x = float(x)
+        self.y = float(y)
+        return self
+
+    def add(self, other):
+        return Vec2(self.x + other.x, self.y + other.y)
+
+    def sub(self, other):
+        return Vec2(self.x - other.x, self.y - other.y)
+
+    def scale(self, factor):
+        return Vec2(self.x * factor, self.y * factor)
+
+    def length(self):
+        return math.hypot(self.x, self.y)
+
+    def lengthSq(self):
+        return self.x * self.x + self.y * self.y
+
+    def normalized(self):
+        mag = self.length()
+        if mag == 0.0:
+            return Vec2(0.0, 0.0)
+        return Vec2(self.x / mag, self.y / mag)
+
+    def distanceTo(self, other):
+        return math.hypot(self.x - other.x, self.y - other.y)
+
+    def asTuple(self):
+        return (self.x, self.y)
+
+    def __repr__(self):
+        return "Vec2(%.3f, %.3f)" % (self.x, self.y)
+
+
+class Aabb:
+    __slots__ = ("x", "y", "w", "h")
+
+    def __init__(self, x, y, w, h):
+        self.x = float(x)
+        self.y = float(y)
+        self.w = float(w)
+        self.h = float(h)
+
+    @property
+    def left(self):
+        return self.x
+
+    @property
+    def right(self):
+        return self.x + self.w
+
+    @property
+    def top(self):
+        return self.y
+
+    @property
+    def bottom(self):
+        return self.y + self.h
+
+    @property
+    def centerX(self):
+        return self.x + self.w * 0.5
+
+    @property
+    def centerY(self):
+        return self.y + self.h * 0.5
+
+    @property
+    def center(self):
+        return Vec2(self.centerX, self.centerY)
+
+    def copy(self):
+        return Aabb(self.x, self.y, self.w, self.h)
+
+    def moved(self, dx, dy):
+        return Aabb(self.x + dx, self.y + dy, self.w, self.h)
+
+    def intersects(self, other):
+        return (
+            self.left < other.right
+            and self.right > other.left
+            and self.top < other.bottom
+            and self.bottom > other.top
+        )
+
+    def touches(self, other):
+        return (
+            self.left <= other.right
+            and self.right >= other.left
+            and self.top <= other.bottom
+            and self.bottom >= other.top
+        )
+
+    def containsPoint(self, px, py):
+        return self.left <= px <= self.right and self.top <= py <= self.bottom
+
+    def overlapArea(self, other):
+        overlapX = min(self.right, other.right) - max(self.left, other.left)
+        overlapY = min(self.bottom, other.bottom) - max(self.top, other.top)
+        if overlapX <= 0.0 or overlapY <= 0.0:
+            return 0.0
+        return overlapX * overlapY
+
+    def inflated(self, marginX, marginY):
+        return Aabb(
+            self.x - marginX,
+            self.y - marginY,
+            self.w + marginX * 2.0,
+            self.h + marginY * 2.0,
+        )
+
+    def asTuple(self):
+        return (self.x, self.y, self.w, self.h)
+
+    def asIntRect(self):
+        return (int(self.x), int(self.y), int(self.w), int(self.h))
+
+    def __repr__(self):
+        return "Aabb(%.2f, %.2f, %.2f, %.2f)" % (self.x, self.y, self.w, self.h)
+
+
+def clamp(value, low, high):
+    if value < low:
+        return low
+    if value > high:
+        return high
+    return value
+
+
+def sign(value):
+    if value > 0:
+        return 1
+    if value < 0:
+        return -1
+    return 0
+
+
+def approach(current, target, delta):
+    if current < target:
+        return min(current + delta, target)
+    return max(current - delta, target)