From b17014e6d6f8252c48e737358e5f303b673e922f Mon Sep 17 00:00:00 2001
From: core <core@coredoes.dev>
Date: Sun, 16 Apr 2023 18:28:57 -0400
Subject: [PATCH] working on vis_viva

---
 server/src/orbit/mod.rs      |  3 ++-
 server/src/orbit/orbit.rs    | 19 +++++++++++++++++++
 server/src/orbit/vis_viva.rs |  3 +++
 server/src/planet.rs         |  2 +-
 4 files changed, 25 insertions(+), 2 deletions(-)
 create mode 100644 server/src/orbit/vis_viva.rs

diff --git a/server/src/orbit/mod.rs b/server/src/orbit/mod.rs
index a8121661d1ada07057f8217e2300a68f3c19d145..818ce8bf162203fc960dfa5b841e16479ec8191a 100644
--- a/server/src/orbit/mod.rs
+++ b/server/src/orbit/mod.rs
@@ -1,4 +1,5 @@
 pub mod constants;
 pub mod orbit;
 pub mod newtonian;
-pub mod kepler;
\ No newline at end of file
+pub mod kepler;
+pub mod vis_viva;
\ No newline at end of file
diff --git a/server/src/orbit/orbit.rs b/server/src/orbit/orbit.rs
index 9e7ff2ce845d4a503766e4b01d76acae46e1370e..05a609e76b5e32bbd5c95d4a6a7563709f06835b 100644
--- a/server/src/orbit/orbit.rs
+++ b/server/src/orbit/orbit.rs
@@ -3,6 +3,25 @@
 
 use nalgebra::{vector, Vector2};
 use crate::orbit::newtonian::solve_kepler_with_newtonian;
+use crate::orbit::vis_viva::vis_viva;
+use crate::planet::GRAVITY;
+
+pub fn calculate_vector_of_orbit(periapsis: f64, apoapsis: f64, t: f64, mass_of_bigger: f64) -> Vector2<f64> {
+    let semi_major_length = (apoapsis + periapsis) / 2.0;
+    let linear_eccentricity = semi_major_length - periapsis; // distance between center and focus
+    let eccentricity = linear_eccentricity / semi_major_length; // 0: circle. 1: parabola. in between: ellipse
+
+    let distances = calculate_point_on_orbit(periapsis, apoapsis, t);
+    let distance_x = distances[0];
+    let distance_y = distances[1];
+
+    let distance = (distance_x * distance_x + distance_y * distance_y).sqrt();
+
+    let velocity = vis_viva(distance, semi_major_length, GRAVITY, mass_of_bigger);
+
+    let ellipse_center_x = -linear_eccentricity;
+    let ellipse_center_y = apoapsis - semi_major_length;
+}
 
 pub fn calculate_point_on_orbit(periapsis: f64, apoapsis: f64, t: f64) -> Vector2<f64> {
     let semi_major_length = (apoapsis + periapsis) / 2.0;
diff --git a/server/src/orbit/vis_viva.rs b/server/src/orbit/vis_viva.rs
new file mode 100644
index 0000000000000000000000000000000000000000..22c9a17e966d1b43e20a5432efcd0600600a32c6
--- /dev/null
+++ b/server/src/orbit/vis_viva.rs
@@ -0,0 +1,3 @@
+pub fn vis_viva(distance_between_centers: f64, semi_major: f64, g: f64, mass_of_bigger: f64) -> f64 {
+    (g * mass_of_bigger * (2.0 / distance_between_centers - 1.0 / semi_major)).sqrt()
+}
\ No newline at end of file
diff --git a/server/src/planet.rs b/server/src/planet.rs
index 51371ff658118f41846e8a79452026be0b052d84..bfee762da621f5a72e2347fa68378930a7af4467 100644
--- a/server/src/planet.rs
+++ b/server/src/planet.rs
@@ -8,7 +8,7 @@ use crate::orbit::constants::{EARTH_MASS, EARTH_RADIUS, MOON_APOAPSIS, MOON_MASS
 use crate::orbit::orbit::{calculate_point_on_orbit, calculate_world_position_of_orbit};
 
 //const GRAVITY: f64 = 0.001;
-const GRAVITY: f64 = 12.6674;
+pub const GRAVITY: f64 = 12.6674;
 
 #[derive(Clone)]
 pub struct Planet {