From f5929e9dc0a9bfa6e06b0c47499763345d69c1d0 Mon Sep 17 00:00:00 2001
From: march3 <gang.wei@qq.com>
Date: Sat, 8 Apr 2023 12:38:54 +0800
Subject: [PATCH] =?UTF-8?q?Python=E8=B6=85=E4=BA=BA-=E5=AE=87=E5=AE=99?=
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---
 simulators/ursina/entities/body_timer.py | 20 ++++++++++++++------
 1 file changed, 14 insertions(+), 6 deletions(-)

diff --git a/simulators/ursina/entities/body_timer.py b/simulators/ursina/entities/body_timer.py
index 0456bbd..f6764c8 100644
--- a/simulators/ursina/entities/body_timer.py
+++ b/simulators/ursina/entities/body_timer.py
@@ -18,12 +18,15 @@ from simulators.ursina.ursina_event import UrsinaEvent
 
 class BodyTimer(Singleton):
     """
-    天体计时器
+    天体计时器，原理就是:
+       以 BodyTimer 为一个天体在宇宙中运行，以速度 self.velocity_inc 递增。
+       通过公式： 速度 * 时间 = 距离，获取到累计距离， self.position_sum += self.velocity_inc * dt
+       最后通过公式： 时间 = 距离 / 速度， 从而得到天体运行了多长时间
     """
 
     def __init__(self):
         if not hasattr(self, "inited"):
-            self.velocity_inc = 0.00001
+            self.velocity_inc = 1e-30  # 理论上数值越小越好，可以使用 1e-300 ，但建议使用：1e-30   # 0.00001
             UrsinaEvent.on_reset_subscription(self.reset)
             UrsinaEvent.on_pause_subscription(self.pause)
             UrsinaEvent.on_start_subscription(self.start)
@@ -36,14 +39,19 @@ class BodyTimer(Singleton):
         pass
 
     def reset(self):
+        # 累计距离置零
         self.position_sum = 0.0
 
     def calc_time(self, dt):
         if not hasattr(self, "position_sum"):
+            # 累计距离置零
             self.position_sum = 0.0
+        # 通过公式： 速度 * 时间 = 距离，获取到累计距离
         self.position_sum += self.velocity_inc * dt
+
         # 距离(km) / 速度(km/s) = 时间(s)
         seconds = round(self.position_sum / self.velocity_inc)
+        # 获取到 seconds 后，通过下面的计算得到时分秒、年、天
         hours, remainder = divmod(seconds, 3600)
         minutes, seconds = divmod(remainder, 60)
         days, hours = divmod(hours, 24)
@@ -52,14 +60,14 @@ class BodyTimer(Singleton):
         if days > 1:
             s_days = str(days).rjust(3, " ")
             if days >= 20 or years >= 1:
-                self.text = f'{int(years)}年{s_days}天'
+                time_text = f'{int(years)}年{s_days}天'
             else:
-                self.text = f'{int(days)}天 {int(hours):02d}:{int(minutes):02d}:{int(seconds):02d}'
+                time_text = f'{int(days)}天 {int(hours):02d}:{int(minutes):02d}:{int(seconds):02d}'
         else:
-            self.text = f'{int(hours):02d}:{int(minutes):02d}:{int(seconds):02d}'
+            time_text = f'{int(hours):02d}:{int(minutes):02d}:{int(seconds):02d}'
 
         # print(self.text)
-        UrsinaEvent.on_timer_changed(self.text, (years, days, hours, minutes, seconds))
+        UrsinaEvent.on_timer_changed(time_text, (years, days, hours, minutes, seconds))
 
     def ignore_gravity(self, body):
         return True
-- 
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