feat: bodies attract

include/sims.hpp

@@ -1,21 +1,23 @@
 #ifndef SIMS_HPP
 #define SIMS_HPP
 
+#include "utils.hpp"
 #include <SDL3/SDL_pixels.h>
 #include <SDL3/SDL_render.h>
 #include <utility>
 
 class Body {
 private:
+        std::pair<float, float> old_positions[200];
+
+public:
     float x;
     float y;
     float vx = 1;
     float vy = 1;
-    std::pair<float, float> old_positions[200];
-
-public:
     SDL_Renderer* renderer;
     SDL_Color color = {255, 255, 255, 255}; // white
+    long double mass = EARTH_MASS;
 
     Body(int x_pos, int y_pos);
 
@@ -23,6 +25,7 @@ public:
     void live();
 };
 
-void two_bodies(SDL_Renderer* r, Body &a, Body &b);
+void two_bodies(SDL_Renderer* renderer, Body &a, Body &b);
+Body create_random_body();
 
 #endif

include/utils.hpp

@@ -0,0 +1,13 @@
+#ifndef UTILS_H
+#define UTILS_H
+
+#include <utility>
+
+// constants
+
+const long double EARTH_MASS =  5.972e24;
+const long double G = 6.67430e-11L;
+
+std::pair<int, int> get_random_position(int x_min, int x_max, int y_min, int y_max);
+
+#endif