Fixed some things, broke some things, we now have some sort of a config idk timestep broken

CMakeLists.txt

@@ -24,6 +24,7 @@ add_executable(${PROJECT_NAME}
     mechanics.c
     vec_utils.c
     gravity.c
+    magnetism.c
 )
 
 target_link_libraries(${PROJECT_NAME}
@@ -31,9 +32,10 @@ target_link_libraries(${PROJECT_NAME}
         raylib
 )
 
-target_compile_options(${PROJECT_NAME}
-    PRIVATE
-        -Wall
-        -Wextra
-        -Wpedantic
+target_compile_options(${PROJECT_NAME} PRIVATE
+      -Wall
+      -Wextra
+      -Wpedantic
+    $<$<CONFIG:Debug>:-ggdb -O0>
+    $<$<CONFIG:Release>:-O3>
 )

config.fphy

@@ -0,0 +1,38 @@
+mass(EARTH_MASS), radius(km), {x(UA), y(UA)}, {vx(km/s), vy(km/s)}, draw_radius(km), charge(C), name
+330432.0, 696340.0, {0, 0}, {0, 0}, 696340, 0, Sun
+0.055, 2439.7, {0.387, 0}, {0, -38.86}, 80, 0, Mercury
+0.815, 6051.8, {0.723, 0}, {0, -34.79}, 190, 0, Venus
+1.0, 6371.0, {1.0, 0}, {0, -29.29}, 200, 0, Earth
+0.107, 3389.5, {1.524, 0}, {0, -21.97}, 106, 0, Mars
+317.83, 69911.0, {5.203, 0}, {0, -12.43}, 400, 0, Jupiter
+95.159, 58232.0, {9.582, 0}, {0, -9.11}, 300, 0, Saturn
+14.536, 25362.0, {19.201, 0}, {0, -6.80}, 250, 0, Uranus
+17.147, 24622.0, {30.069, 0}, {0, -5.43}, 250, 0, Neptune
+0.012294, 1737.4, {1.002570, 0}, {0, -30.3083}, 60, 0, Moon
+0.000000001775, 11.27, {1.524063, 0}, {0, -24.1070}, 20, 0, Phobos
+0.000000000402, 6.20, {1.524157, 0}, {0, -23.3212}, 16, 0, Deimos
+0.00000001674, 21.5, {5.203856, 0}, {0, -43.8901}, 15, 0, Metis
+0.00000000335, 8.2, {5.203862, 0}, {0, -43.7679}, 12, 0, Adrastea
+0.000001256, 83.5, {5.204213, 0}, {0, -38.8569}, 20, 0, Amalthea
+0.000000134, 49.3, {5.204483, 0}, {0, -36.3239}, 18, 0, Thebe
+0.014956, 1821.49, {5.205820, 0}, {0, -29.7605}, 65, 0, Io
+0.008037, 1560.80, {5.207486, 0}, {0, -26.1695}, 60, 0, Europa
+0.024813, 2631.20, {5.210155, 0}, {0, -23.3091}, 75, 0, Ganymede
+0.018015, 2410.30, {5.215585, 0}, {0, -20.6330}, 70, 0, Callisto
+0.000001591, 85.0, {5.279739, 0}, {0, -15.7520}, 20, 0, Himalia
+0.000006346, 198.2, {9.583240, 0}, {0, -23.4089}, 24, 0, Mimas
+0.000018084, 252.1, {9.583591, 0}, {0, -21.7338}, 28, 0, Enceladus
+0.000103479, 531.1, {9.583970, 0}, {0, -20.4559}, 36, 0, Tethys
+0.000184187, 561.4, {9.584523, 0}, {0, -19.1353}, 38, 0, Dione
+0.000386792, 763.8, {9.585523, 0}, {0, -17.5935}, 44, 0, Rhea
+0.0225294, 2575.0, {9.590168, 0}, {0, -14.6817}, 75, 0, Titan
+0.000000938, 135.0, {9.592033, 0}, {0, -14.1371}, 20, 0, Hyperion
+0.000303071, 734.5, {9.605803, 0}, {0, -12.3738}, 42, 0, Iapetus
+0.000011051, 235.8, {19.201865, 0}, {0, -13.4917}, 25, 0, Miranda
+0.000226047, 578.9, {19.202277, 0}, {0, -12.3074}, 38, 0, Ariel
+0.000195908, 584.7, {19.202780, 0}, {0, -11.4645}, 38, 0, Umbriel
+0.000589398, 788.9, {19.203914, 0}, {0, -10.4458}, 45, 0, Titania
+0.000504002, 761.4, {19.204901, 0}, {0, -9.9511}, 44, 0, Oberon
+0.000008372, 210.0, {30.069686, 0}, {0, -13.0522}, 25, 0, Proteus
+0.00358327, 1353.4, {30.071271, 0}, {0, -1.0406}, 55, 0, Triton
+0.000005023, 170.0, {30.105758, 0}, {0, -6.5434}, 23, 0, Nereid

consts.h

@@ -1,7 +1,16 @@
 #ifndef CONSTS_H_
 #define CONSTS_H_
-#define TIMESTEP 1000000
-#define simx 2
+#define LOOP_TIMESTEP                                                          \
+  1000000LL // Wall-clock nanoseconds between updates (1 kHz).
+#define PHYSICS_TIMESTEP 10.0f // Simulated seconds per update.
+#define WALL_COLLISIONS 0      // Enable for bounded collision tests.
 #define NEWTON_G 6.674e-11
+#define EARTH_MASS 5.9722e24 // Kilograms per simulation mass unit.
+#define UA 149.6E6
+#define EARTH_RADIUS 6378.14 // Kilometers per simulation distance unit.
+#define DISTANCE_UNIT_METERS (EARTH_RADIUS * 1000.0)
+#define SIMULATION_G                                                           \
+  (NEWTON_G * EARTH_MASS /                                                     \
+   (DISTANCE_UNIT_METERS * DISTANCE_UNIT_METERS * DISTANCE_UNIT_METERS))
 
 #endif // CONSTS_H_

gravity.c

@@ -4,23 +4,22 @@
 #include <raylib.h>
 
 void gravity(universe_t *uni) {
-  mass_body_t body_1;
-  mass_body_t body_2;
-  for (unsigned int i = 0; i < uni->num_bodies - 1; i++) {
-    body_1 = uni->bodies[i];
+  const float dt = PHYSICS_TIMESTEP;
+  for (unsigned int i = 0; i < uni->num_bodies; i++) {
+    mass_body_t *body_1 = &uni->bodies[i];
     for (unsigned int y = i + 1; y < uni->num_bodies; y++) {
-      body_2 = uni->bodies[y];
-      float force =
-          simx * NEWTON_G * body_1.mass * body_2.mass /
-          (vec2_len(vec2_diff(body_2.position, body_1.position)) * TIMESTEP);
-      Vector2 acceleration =
-          vec2_normalize(vec2_diff(body_2.position, body_1.position));
-      Vector2 acceleration_1 = vec2_scale(acceleration, force / body_1.mass);
-      Vector2 acceleration_2 = vec2_scale(acceleration, -force / body_2.mass);
-      body_1.speed = vec2_sum(body_1.speed, acceleration_1);
-      body_2.speed = vec2_sum(body_1.speed, acceleration_2);
-      uni->bodies[y] = body_2;
+      mass_body_t *body_2 = &uni->bodies[y];
+      Vector2 separation = vec2_diff(body_2->position, body_1->position);
+      float distance_squared = vec2_dot(separation, separation);
+      if (distance_squared == 0.0f) {
+        continue;
+      }
+      Vector2 direction = vec2_normalize(separation);
+      float factor = SIMULATION_G * dt / distance_squared;
+      body_1->speed =
+          vec2_sum(body_1->speed, vec2_scale(direction, factor * body_2->mass));
+      body_2->speed = vec2_sum(body_2->speed,
+                               vec2_scale(direction, -factor * body_1->mass));
     }
-    uni->bodies[i] = body_1;
   }
 }

magnetism.c

@@ -6,19 +6,27 @@
 #define EPSILON 8.85418782E-12
 
 void magnetism(universe_t* uni){
-  mass_body_t body_1;
-  mass_body_t body_2;
-  Vector2 diff, force;
-  for (unsigned int i = 0; i < uni->num_bodies-1; i++) {
-    body_1 = uni->bodies[i];
-      for (unsigned int y = i + 1; y < uni->num_bodies; y++) {
-        body_2 = uni->bodies[y];
-        diff=vec2_diff(body_2.position,body_1.position);
-        force = vec2_scale(diff,body_1.charge*body_2.charge/(4*PI*EPSILON*vec2_len(diff)));
-        body_1.speed=vec2_sum(body_1.speed,vec2_scale(force,1/body_1.mass));
-        body_2.speed=vec2_diff(body_2.speed,vec2_scale(force,1/body_2.mass));
-        uni->bodies[y] = body_2;
+  for (unsigned int i = 0; i < uni->num_bodies; i++) {
+    mass_body_t *body_1 = &uni->bodies[i];
+    for (unsigned int y = i + 1; y < uni->num_bodies; y++) {
+      mass_body_t *body_2 = &uni->bodies[y];
+      if (body_1->charge == 0 || body_2->charge == 0) {
+        continue;
+      }
+      Vector2 diff = vec2_diff(body_2->position, body_1->position);
+      float distance_squared = vec2_dot(diff, diff);
+      if (distance_squared == 0) {
+        continue;
+      }
+      // Charges are in coulombs; convert acceleration to Earth radii/s^2.
+      float factor = PHYSICS_TIMESTEP * body_1->charge * body_2->charge /
+                     (4 * PI * EPSILON * EARTH_MASS * DISTANCE_UNIT_METERS *
+                      DISTANCE_UNIT_METERS * DISTANCE_UNIT_METERS * distance_squared);
+      Vector2 impulse = vec2_scale(vec2_normalize(diff), factor);
+      body_1->speed = vec2_diff(body_1->speed,
+                               vec2_scale(impulse, 1 / body_1->mass));
+      body_2->speed = vec2_sum(body_2->speed,
+                              vec2_scale(impulse, 1 / body_2->mass));
     }
-    uni->bodies[i] = body_1;
   }
 }

main.c

@@ -2,19 +2,17 @@
 
 #include "consts.h"
 #include "gravity.h"
-#include "mechanics.h"
-<<<<<<< HEAD
 #include "magnetism.h"
-=======
+#include "mechanics.h"
 #include "objects.h"
->>>>>>> aa4f0dfe52bab37ef3bf82a47c44316c74c3ccbc
-#include <bits/time.h>
+#include "vec_utils.h"
+#include <errno.h>
 #include <math.h>
 #include <pthread.h>
 #include <raylib.h>
 #include <stdio.h>
 #include <stdlib.h>
-#include <threads.h>
+#include <string.h>
 #include <time.h>
 #include <unistd.h>
 
@@ -26,48 +24,76 @@ static inline int center_y_text(int height, int size) {
   return (height - size) / 2;
 }
 
-long long timespec_diff_ns(struct timespec end, struct timespec start) {
-  return (end.tv_sec - start.tv_sec) * 1000000000LL +
-         (end.tv_nsec - start.tv_nsec);
-}
-
 void *physics(void *args) {
   universe_t *uni = (universe_t *)args;
-  struct timespec ot, ct;
+  struct timespec next_step;
+  clock_gettime(CLOCK_MONOTONIC, &next_step);
   while (true) {
-    printf("a");
-    clock_gettime(CLOCK_MONOTONIC, &ct);
-    // gravity(uni);
-    mechanics(uni);
-    magnetism(uni);
-    ot = ct;
-    long long elapsed = timespec_diff_ns(ct, ot);
-    long long remaining = TIMESTEP / simx - elapsed;
-
-    if (remaining > 0) {
-      long long sleep_time = remaining * 9 / 10;
-
-      struct timespec sleep_time_spec = {0, sleep_time};
-      thrd_sleep(&sleep_time_spec, NULL);
+    next_step.tv_sec += LOOP_TIMESTEP / 1000000000LL;
+    next_step.tv_nsec += LOOP_TIMESTEP % 1000000000LL;
+    if (next_step.tv_nsec >= 1000000000L) {
+      next_step.tv_nsec -= 1000000000L;
+      next_step.tv_sec++;
+    }
+    gravity(uni);
+    magnetism(uni);
+    mechanics(uni);
+    struct timespec now;
+    clock_gettime(CLOCK_MONOTONIC, &now);
+    if (now.tv_sec > next_step.tv_sec ||
+        (now.tv_sec == next_step.tv_sec && now.tv_nsec > next_step.tv_nsec)) {
+      next_step =
+          now; // An overrun starts a fresh schedule, without catch-up steps.
+    }
+    // Sleep only until the deadline; processing time is already included.
+    while (clock_nanosleep(CLOCK_MONOTONIC, TIMER_ABSTIME, &next_step, NULL) ==
+           EINTR) {
     }
-
-    do {
-      clock_gettime(CLOCK_MONOTONIC, &ct);
-    } while (timespec_diff_ns(ct, ot) < TIMESTEP / simx);
   }
 }
 
-int main(void) {
+int main(int argc, char **argv) {
+  if (argc != 2) {
+    printf("No config provided\n");
+    return EXIT_FAILURE;
+  }
+  FILE *file = fopen(argv[1], "r");
+  if (file == NULL) {
+    printf("File not found");
+    return EXIT_FAILURE;
+  }
+  int cam_lock = -1;
   float v_scale = 1;
   Vector2 canvas_offset = {0, 0};
   pthread_t physics_thread;
   const char *welcome_text = "Welcome to Fucked Physics!";
   universe_t universe = {0, NULL};
   universe.bodies = malloc(1024 * sizeof(mass_body_t));
-  universe.num_bodies = 2;
+  universe.num_bodies = 0;
+  char line[1024];
+  fgets(line, 1024, file);
+  while (fgets(line, 1024, file)) {
+    printf("%s", line);
+    float mass, radius, x, y, vx, vy, draw_radius, charge;
+    char name[32];
+    sscanf(line, "%f, %f, {%f, %f}, {%f, %f}, %f, %f, %31s", &mass, &radius, &x,
+           &y, &vx, &vy, &draw_radius, &charge, name);
+
+    universe.bodies[universe.num_bodies] = (mass_body_t){
+        .mass = mass,
+        .radius = radius / EARTH_RADIUS,
+        .position = (Vector2){x * UA / EARTH_RADIUS, y * UA / EARTH_RADIUS},
+        .speed = (Vector2){vx / EARTH_RADIUS, vy / EARTH_RADIUS},
+        .draw_radius = draw_radius / EARTH_RADIUS,
+        .charge = charge};
+
+    memcpy((void *)&universe.bodies[universe.num_bodies].name, (void *)&name,
+           32);
+    universe.num_bodies++;
+  }
+
+  fclose(file);
 
-  universe.bodies[0] = (mass_body_t){100000000000.0f, 200, {0, 0}, {0, 0}};
-  universe.bodies[1] = (mass_body_t){100, 50, {500, 0}, {0, 2}};
   SetConfigFlags(FLAG_WINDOW_RESIZABLE);
   InitWindow(800, 450, "Fucked Physics");
   SetTargetFPS(120);
@@ -80,12 +106,10 @@ int main(void) {
       key_pressed = GetKeyPressed();
       switch (key_pressed) {
       case KEY_I:
-        v_scale += 0.1;
+        v_scale *= 1.26;
         break;
       case KEY_O:
-        if (v_scale > 0.1) {
-          v_scale -= 0.1;
-        }
+        v_scale /= 1.26;
         break;
       case KEY_LEFT:
         canvas_offset.x += 100;
@@ -99,42 +123,82 @@ int main(void) {
       case KEY_DOWN:
         canvas_offset.y -= 100;
         break;
+      case KEY_ONE:
+        cam_lock = 1;
+        break;
+      case KEY_TWO:
+        cam_lock = 2;
+        break;
+      case KEY_THREE:
+        cam_lock = 3;
+        break;
+      case KEY_FOUR:
+        cam_lock = 4;
+        break;
+      case KEY_FIVE:
+        cam_lock = 5;
+        break;
+      case KEY_SIX:
+        cam_lock = 6;
+        break;
+      case KEY_SEVEN:
+        cam_lock = 7;
+        break;
+      case KEY_EIGHT:
+        cam_lock = 8;
+        break;
+      case KEY_NINE:
+        cam_lock = 9;
+        break;
+      case KEY_ZERO:
+        cam_lock = 0;
+        break;
+      case KEY_F:
+        cam_lock = -1;
       }
     } while (key_pressed != 0);
 
-    if (canvas_offset.x + GetRenderWidth() * 0.5 / v_scale >
-        GetRenderWidth() * 5) {
-      canvas_offset.x =
-          -GetRenderWidth() * 0.5 / v_scale + GetRenderWidth() * 5;
-    } else if (canvas_offset.x - GetRenderWidth() * 0.5 / v_scale <
-               -GetRenderWidth() * 5) {
-      canvas_offset.x = GetRenderWidth() * 0.5 / v_scale - GetRenderWidth() * 5;
-    }
+    if (universe.num_bodies < 1024 &&
+        (IsMouseButtonPressed(MOUSE_LEFT_BUTTON) ||
+         IsMouseButtonDown(MOUSE_RIGHT_BUTTON))) {
+      Vector2 mouse_pos = vec2_scale(
+          transform_to_center(vec2_scale(GetMousePosition(), -1)), -1);
+      mouse_pos = vec2_scale(mouse_pos, 1 / v_scale);
 
-    if (canvas_offset.y + GetRenderHeight() * 0.5 / v_scale >
-        GetRenderHeight() * 5) {
-      canvas_offset.y =
-          -GetRenderHeight() * 0.5 / v_scale + GetRenderHeight() * 5;
-    } else if (canvas_offset.y - GetRenderHeight() * 0.5 / v_scale <
-               -GetRenderHeight() * 5) {
-      canvas_offset.y =
-          GetRenderHeight() * 0.5 / v_scale - GetRenderHeight() * 5;
+      universe.bodies[universe.num_bodies] =
+          (mass_body_t){100000.0f, 0.1, mouse_pos, {0, 0}, 10, 0, ""};
+      snprintf(universe.bodies[universe.num_bodies].name,
+               sizeof(universe.bodies[universe.num_bodies].name), "Body %u",
+               universe.num_bodies + 1);
+      universe.num_bodies++;
     }
 
     BeginDrawing();
     ClearBackground(RAYWHITE);
     for (unsigned int i = 0; i < universe.num_bodies; i++) {
-      Vector2 scaled_offset = vec2_scale(canvas_offset, v_scale);
+      Vector2 local_offset = canvas_offset;
+      if (cam_lock != -1) {
+        local_offset = vec2_scale(universe.bodies[cam_lock].position, -1);
+      }
+      Vector2 scaled_offset = vec2_scale(local_offset, v_scale);
       Vector2 body_position = vec2_scale(universe.bodies[i].position, v_scale);
       body_position = vec2_sum(body_position, scaled_offset);
-      DrawCircleV(transform_to_center(body_position),
-                  universe.bodies[i].radius * v_scale,
-                  (Color){((256 / universe.num_bodies) * i) % 256,
-                          255 * (i % 2), 255 * (i % 2) * (i % 3), 255});
+      body_position = transform_to_center(body_position);
+      float draw_radius = universe.bodies[i].draw_radius * v_scale;
+      if (draw_radius < 2) {
+        draw_radius = 2;
+      }
+      DrawCircleV(body_position, draw_radius,
+                  (Color){((256 / universe.num_bodies) * i) % 256 / 2,
+                          255 * (i % 2) / 2, 255 * (i % 2) * (i % 3) / 2, 255});
+      // Keep labels readable at every zoom level.
+      DrawText(universe.bodies[i].name,
+               (int)(body_position.x + draw_radius + 6),
+               (int)(body_position.y - 8), 16, BLACK);
     }
 
-    DrawText(welcome_text, center_x_text(welcome_text, GetRenderWidth(), 20),
-             center_y_text(GetRenderHeight(), 20), 20, BLACK);
+    // DrawText(welcome_text, center_x_text(welcome_text, GetRenderWidth(), 20),
+    //          center_y_text(GetRenderHeight(), 20), 20, BLACK);
     EndDrawing();
   }
 

mechanics.c

@@ -48,8 +48,8 @@ void collide(mass_body_t *a, mass_body_t *b, const Vector2 normal,
 }
 
 void collide_rigid(mass_body_t *a, float restitution) {
-  float max_x = GetRenderWidth() * 10 / 2.0f - a->radius;
-  float max_y = GetRenderHeight() * 10 / 2.0f - a->radius;
+  float max_x = GetRenderWidth() * 100 / 2.0f - a->radius;
+  float max_y = GetRenderHeight() * 100 / 2.0f - a->radius;
 
   if (a->position.x > max_x) {
     a->position.x = max_x;
@@ -73,25 +73,23 @@ void collide_rigid(mass_body_t *a, float restitution) {
 }
 
 void mechanics(universe_t *uni) {
-  mass_body_t body_1;
-  mass_body_t body_2;
-  Vector2 collision;
-  Vector2 scaled_speed;
+  // Advance every body to the same simulated time before checking contacts.
   for (unsigned int i = 0; i < uni->num_bodies; i++) {
-    body_1 = uni->bodies[i];
-    scaled_speed = vec2_scale(body_1.speed, 1.0 / simx);
-    body_1.position = vec2_sum(body_1.position, scaled_speed);
-    if (i < uni->num_bodies - 1) {
-      for (unsigned int y = i + 1; y < uni->num_bodies; y++) {
-        body_2 = uni->bodies[y];
-        collision = body_collision(&body_1, &body_2);
-        if (!vec2_is_null(collision)) {
-          collide(&body_1, &body_2, collision, 1.0);
-        }
-        uni->bodies[y] = body_2;
+    mass_body_t *body = &uni->bodies[i];
+    body->position = vec2_sum(body->position,
+                             vec2_scale(body->speed, PHYSICS_TIMESTEP));
+  }
+  for (unsigned int i = 0; i < uni->num_bodies; i++) {
+    mass_body_t *body_1 = &uni->bodies[i];
+    for (unsigned int y = i + 1; y < uni->num_bodies; y++) {
+      mass_body_t *body_2 = &uni->bodies[y];
+      Vector2 collision = body_collision(body_1, body_2);
+      if (!vec2_is_null(collision)) {
+        collide(body_1, body_2, collision, 0.99);
       }
     }
-    collide_rigid(&body_1, 1.1);
-    uni->bodies[i] = body_1;
+    if (WALL_COLLISIONS) {
+      collide_rigid(body_1, 1.0f);
+    }
   }
 }

objects.h

@@ -3,11 +3,13 @@
 #include "vec_utils.h"
 
 typedef struct {
-  float mass;
-  float radius;
-  Vector2 position;
-  Vector2 speed;
-  float charge;
+  float mass; // Earth masses.
+  float radius; // Earth radii (physical collision radius).
+  Vector2 position; // Earth radii.
+  Vector2 speed; // Earth radii per simulated second.
+  float draw_radius;
+  float charge; // Coulombs.
+  char name[32];
 } mass_body_t;
 
 typedef struct universe {

three.fphy

@@ -0,0 +1,4 @@
+mass(EARTH_MASS), radius(km), {x(UA), y(UA)}, {vx(km/s), vy(km/s)}, draw_radius(km), charge(C), name
+396518.4, 760000, {-0.85, 0}, {0, 45.0}, 220000, 0, Alpha
+297388.8, 650000, {-0.35, 0}, {0, -37.0}, 200000, 0, Beta
+495648.0, 900000, {1.30, 0}, {0, -14.5}, 250000, 0, Gamma