feat: add camera class

src/camera.py

@@ -0,0 +1,43 @@
+from src.vec import Vec
+
+
+class Camera:
+    UNIT_RATIO = 150
+
+    def __init__(self) -> None:
+        self.pos: Vec = Vec()
+        self.up: Vec = Vec(0, -1)
+        self.size: Vec = Vec(600, 600)
+        self.zoom: float = 1
+
+    def set_pos(self, pos: Vec):
+        self.pos = pos
+
+    def set_direction(self, up: Vec):
+        self.up = up.normalized
+
+    def set_size(self, size: Vec):
+        self.size = size
+
+    @property
+    def center(self) -> Vec:
+        return self.size / 2
+
+    def screen2world(self, screen_pos: Vec) -> Vec:
+        delta: Vec = screen_pos - self.center
+        delta /= self.zoom * self.UNIT_RATIO
+        dx: float = delta.x
+        dy: float = delta.y
+
+        v1: Vec = self.up.perp * dx
+        v2: Vec = self.up * dy
+
+        return self.pos + v1 + v2
+
+    def world2screen(self, world_pos: Vec) -> Vec:
+        delta: Vec = world_pos - self.pos
+        dy: float = -delta.dot(self.up)
+        dx: float = delta.dot(self.up.perp)
+        screen_delta: Vec = Vec(dx, dy) * self.zoom * self.UNIT_RATIO
+        screen_pos: Vec = self.center + screen_delta
+        return screen_pos