From 39013a210e0d898ec781037a8ea427a179720b9d Mon Sep 17 00:00:00 2001
From: march3 <gang.wei@qq.com>
Date: Sun, 16 Apr 2023 20:53:58 +0800
Subject: [PATCH] =?UTF-8?q?Python=E8=B6=85=E4=BA=BA-=E5=AE=87=E5=AE=99?=
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---
 sim_scenes/science/free_fall_of_ball.py    | 34 ++++++++++++----------
 simulators/ursina/entities/entity_utils.py |  1 -
 simulators/ursina/entities/planet.py       |  1 +
 3 files changed, 19 insertions(+), 17 deletions(-)

diff --git a/sim_scenes/science/free_fall_of_ball.py b/sim_scenes/science/free_fall_of_ball.py
index ff85488..7681188 100644
--- a/sim_scenes/science/free_fall_of_ball.py
+++ b/sim_scenes/science/free_fall_of_ball.py
@@ -17,22 +17,24 @@ if __name__ == '__main__':
     """
     # 地球在中心位置
     earth = Earth(init_position=[0, 0, 0], size_scale=1, texture="earth_hd.jpg", init_velocity=[0, 0, 0])
-    # e.raduis = 6373.22
-    # math.sqrt(pow(6373.22 + 500, 2) + pow(500, 2))-6373.22
-    # math.sqrt(pow(6373.22 + 1000, 2) + pow(500, 2))-6373.22
-    # 创建的3个不同质量，不同高度的物体，观察地球表面上的加速度
-    bodies = [
-        earth,
-        Football(mass=500, size_scale=3e2, trail_color=[255, 0, 0],
-                 init_position=[-500, earth.raduis + 500, 0],  # 球在地面上 518 多公里（向左偏移500公里）
-                 init_velocity=[0, 0, 0], gravity_only_for=[earth]),
-        Football(mass=1000, size_scale=3e2, trail_color=[0, 255, 0],
-                 init_position=[0, earth.raduis + 800, 0],  # 球在地面上 800 多公里
-                 init_velocity=[0, 0, 0], gravity_only_for=[earth]),
-        Football(mass=5000, size_scale=3.8e2, trail_color=[0, 0, 255],
-                 init_position=[500, earth.raduis + 1000, 0],  # 球在地面上 1016 多公里（向右偏移500公里）
-                 init_velocity=[0, 0, 0], gravity_only_for=[earth]),
-    ]
+    # earth.raduis = 6373.22
+    # 创建的3个不同质量，不同高度的球，观察这3个球打到地球表面上的加速度
+    ball_1 = Football(mass=500, size_scale=3e2, trail_color=[255, 0, 0],
+                      # 球在地面上 518 多公里处
+                      # 518 = sqrt[(earth.raduis + 500)² + (-500)²] - earth.raduis
+                      init_position=[-500, earth.raduis + 500, 0],
+                      init_velocity=[0, 0, 0], gravity_only_for=[earth])
+    ball_2 = Football(mass=1000, size_scale=3e2, trail_color=[0, 255, 0],
+                      # 球在地面上 800 多公里处
+                      init_position=[0, earth.raduis + 800, 0],
+                      init_velocity=[0, 0, 0], gravity_only_for=[earth])
+    ball_3 = Football(mass=5000, size_scale=3.8e2, trail_color=[0, 0, 255],
+                      # 球在地面上 1016 多公里处
+                      # 1016 = sqrt[(earth.raduis + 1000)² + 500²] - earth.raduis
+                      init_position=[500, earth.raduis + 1000, 0],
+                      init_velocity=[0, 0, 0], gravity_only_for=[earth])
+
+    bodies = [earth, ball_1, ball_2, ball_3]
 
     # 使用 ursina 查看的运行效果
     # 常用快捷键： P：运行和暂停  O：重新开始  I：显示天体轨迹
diff --git a/simulators/ursina/entities/entity_utils.py b/simulators/ursina/entities/entity_utils.py
index bb9c2f3..369609c 100644
--- a/simulators/ursina/entities/entity_utils.py
+++ b/simulators/ursina/entities/entity_utils.py
@@ -295,4 +295,3 @@ def create_trail_info(body, trail):
     if trail is not None:
         trail.entity_infos = {"velocity": [vel_value, vel_direction, vel_position],
                               "acceleration": [acc_value, acc_direction, acc_position]}
-
diff --git a/simulators/ursina/entities/planet.py b/simulators/ursina/entities/planet.py
index fba2d4b..3af4c91 100644
--- a/simulators/ursina/entities/planet.py
+++ b/simulators/ursina/entities/planet.py
@@ -100,6 +100,7 @@ class Planet(Entity):
         )
         if hasattr(self.body, "rotate_angle"):
             if self.body.rotate_angle != 0:
+                # 为了给天体增加一个倾斜角，增加了一个Entity
                 self.rotate_angle = self.body.rotate_angle
                 self.main_entity = Entity()
                 self.main_entity.rotation_x = self.rotate_angle
-- 
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