Initial

ember.py

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+import pygame
+from typing import Tuple
+import numpy as np
+import pygame.gfxdraw
+from math import ceil
+from config import HEIGHT, WIDTH
+from utils import clamp, mix
+
+BLUR_RADIUS = 3
+TTL_LOSS_NEAR_BORDER_IN_PIXELS = 200
+UP_DRAFT = 300
+
+
+class Ember:
+    def __init__(self):
+        self.reset()
+
+    def reset(self):
+        self.position = (np.random.randint(0, WIDTH), HEIGHT)
+        self.up_draft = np.random.uniform(0.3, 1) * UP_DRAFT
+        self.time_to_live = np.random.uniform(1, 6)
+        self.color_offset = np.random.uniform(0, 1)
+        self.size = np.random.uniform(2.5, 6.5)
+
+    def update(self, velocity: Tuple[float, float], delta_time: float):
+        self.position = (
+            self.position[0] + velocity[0] * delta_time,
+            self.position[1] + (velocity[1] - self.up_draft) * delta_time,
+        )
+        self.time_to_live -= delta_time
+        if self.distance_from_screen_border() < TTL_LOSS_NEAR_BORDER_IN_PIXELS:
+            self.time_to_live = min(
+                self.distance_from_screen_border() / TTL_LOSS_NEAR_BORDER_IN_PIXELS,
+                self.time_to_live,
+            )
+
+        if self.time_to_live < 0:
+            self.reset()
+
+    def draw(self, screen: pygame.Surface):
+        color = (
+            int(mix(255, 189, self.color_offset)),
+            int(mix(165, 40, self.color_offset)),
+            int(mix(0, 40, self.color_offset)),
+            255 * (1 - clamp((0.5 - self.time_to_live) * 2, 0, 1) ** 2),
+        )
+        draw_antialiased_circle(
+            screen, self.position[0], self.position[1], int(self.size), color
+        )
+
+    def distance_from_screen_border(self):
+        return min(
+            self.position[0],
+            WIDTH - self.position[0],
+            self.position[1],
+            # HEIGHT - self.position[1],
+        )
+
+    def __str__(self) -> str:
+        return f"Ember(position={self.position}, velocity={self.velocity}, time_to_live={self.time_to_live})"
+
+
+def draw_antialiased_circle(surface: pygame.Surface, x, y, radius, color):
+    for dx in range(-ceil(radius), ceil(radius) + 1):
+        for dy in range(-ceil(radius), ceil(radius) + 1):
+            distance = ((dx - x % 1) ** 2 + (dy - y % 1) ** 2) ** 0.5 - radius
+            if (
+                distance < 0
+                and 0 <= x + dx < surface.get_width()
+                and 0 <= y + dy < surface.get_height()
+            ):
+                alpha = min(color[3] / 255, -distance / BLUR_RADIUS)
+                value = surface.get_at((int(x + dx), int(y + dy)))
+                surface.set_at(
+                    (int(x + dx), int(y + dy)),
+                    (
+                        mix(value[0], color[0], alpha),
+                        mix(value[1], color[1], alpha),
+                        mix(value[2], color[2], alpha),
+                        mix(value[3], color[3], alpha),
+                    ),
+                )