From 0b08abec603349564ec45c25a62f340bac87e8a1 Mon Sep 17 00:00:00 2001
From: march3 <gang.wei@qq.com>
Date: Sat, 8 Apr 2023 15:28:03 +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/earth/parabolic_curve.py | 41 +++++++++++++++++++++++++++++
 sim_scenes/func.py                  | 14 ++++++++++
 2 files changed, 55 insertions(+)
 create mode 100644 sim_scenes/earth/parabolic_curve.py

diff --git a/sim_scenes/earth/parabolic_curve.py b/sim_scenes/earth/parabolic_curve.py
new file mode 100644
index 0000000..306312a
--- /dev/null
+++ b/sim_scenes/earth/parabolic_curve.py
@@ -0,0 +1,41 @@
+# -*- coding:utf-8 -*-
+# title           :抛物线模拟
+# description     :抛物线模拟
+# author          :Python超人
+# date            :2023-02-11
+# link            :https://gitcode.net/pythoncr/
+# python_version  :3.8
+# ==============================================================================
+from bodies import Moon, Earth, Body
+from common.consts import SECONDS_PER_HOUR, SECONDS_PER_MINUTE
+from sim_scenes.func import ursina_run, get_vector2d_velocity
+
+if __name__ == '__main__':
+    """
+    抛物线模拟
+    """
+    # TODO: 修改抛出物体的速度
+    velocity = 8  # 物体飞不出地球太远，就落地
+    # velocity = 10  # 物体能飞出地球很远，但还是无法摆脱地球引力
+    # velocity = 11.2  # 脱离地球引力直接飞出。速度11.2千米/秒为脱离地球引力的速度叫第二宇宙速度
+
+    # 根据速度、角度获取矢量速度（vx、vy） -> vx² + vy² = velocity²
+    vx, vy = get_vector2d_velocity(velocity, angle=10)
+
+    # 地球在中心位置
+    e = Earth(init_position=[0, 0, 0], size_scale=1, texture="earth_hd.jpg", init_velocity=[0, 0, 0])
+    bodies = [
+        e,
+        Moon(name='小月球', mass=500, size_scale=2e6,
+             init_position=[0, e.raduis + 300, 0],  # 在地球表面上
+             init_velocity=[vx, vy, 0]),
+    ]
+
+    # 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
+    # position = 左-右+、上+下-、前+后-
+    ursina_run(bodies, SECONDS_PER_HOUR / 2,  # 一秒相当于半个小时
+               position=(0, 0, -45000),
+               show_trail=True,
+               show_timer=True,
+               view_closely=0.001)
diff --git a/sim_scenes/func.py b/sim_scenes/func.py
index 271fac2..7bcb635 100644
--- a/sim_scenes/func.py
+++ b/sim_scenes/func.py
@@ -12,6 +12,7 @@ from common.system import System
 from simulators.ursina.ursina_config import UrsinaConfig
 from simulators.ursina.ursina_event import UrsinaEvent
 from common.consts import LIGHT_SPEED
+import math
 
 
 def mayavi_run(bodies, dt=SECONDS_PER_WEEK,
@@ -229,6 +230,19 @@ def create_text_panel(width=0.35, height=.5):
     return text
 
 
+def get_vector2d_velocity(velocity, angle=15):
+    """
+    根据速度、角度获取矢量速度（vx、vy）
+    @param velocity:
+    @param angle:
+    @return:
+    """
+    vy = math.sin(math.pi * angle / 180) * velocity
+    vx = math.cos(math.pi * angle / 180) * velocity
+    # vx² + vy² = velocity²
+    return vx, vy
+
+
 if __name__ == '__main__':
     from bodies import Sun, Earth
 
-- 
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