feat: add collisions

src/car.py

@@ -3,6 +3,7 @@ from math import radians
 import pygame
 
 from src.camera import Camera
+from src.utils import segments_intersect
 from src.vec import Vec
 
 
@@ -13,6 +14,7 @@ class Car:
     COLOR = (230, 150, 80)
     WIDTH = 0.4
     LENGTH = 0.6
+    COLLISION_MARGIN = 0.4
 
     def __init__(self, pos: Vec, direction: Vec) -> None:
         self.pos: Vec = pos
@@ -22,6 +24,7 @@ class Car:
         self.backward: bool = False
         self.left: bool = False
         self.right: bool = False
+        self.colliding: bool = False
 
     def update(self):
         if self.forward:
@@ -45,6 +48,8 @@ class Car:
             self.direction = self.direction.rotate(rotate_angle)
 
         self.speed *= 0.98
+        if abs(self.speed) < 1e-8:
+            self.speed = 0
 
         self.pos += self.direction * self.speed
 
@@ -62,3 +67,30 @@ class Car:
         p3: Vec = pt - u - v
         p4: Vec = pt + u - v
         return [p1, p2, p3, p4]
+
+    def check_collisions(self, polygons: list[list[Vec]]):
+        self.colliding = False
+        corners: list[Vec] = self.get_corners()
+        sides: list[tuple[Vec, Vec]] = [
+            (corners[i], corners[(i + 1) % 4]) for i in range(4)
+        ]
+
+        for polygon in polygons:
+            n_pts: int = len(polygon)
+            for i in range(n_pts):
+                pt1: Vec = polygon[i]
+                pt2: Vec = polygon[(i + 1) % n_pts]
+                d: Vec = pt2 - pt1
+
+                for s1, s2 in sides:
+                    if segments_intersect(s1, s2, pt1, pt2):
+                        self.colliding = True
+                        self.direction = d.normalized
+                        n: Vec = self.direction.perp
+                        dist: float = (self.pos - pt1).dot(n)
+                        if dist < 0:
+                            n *= -1
+                            dist = -dist
+                        self.speed = 0
+                        self.pos = self.pos + n * (self.COLLISION_MARGIN - dist)
+                        return