Implementation done.

src/Simulation.c

@@ -44,6 +44,7 @@ static Charge generate_random_charge() {
  * @param charges_length The number of charges.
  * @return Charge* The charge array.
  */
+#include <stdio.h>
 static Charge *generate_random_charges(Rectangle *universe, int *charges_length) {
     *charges_length = random_number_between(MIN_CHARGES, MAX_CHARGES);
     Charge *charges = (Charge *)malloc(sizeof(Charge) * *charges_length);
@@ -52,9 +53,11 @@ static Charge *generate_random_charges(Rectangle *universe, int *charges_length)
         while (true) {
             Charge charge = generate_random_charge();
 
+            // Checks if the charge is not too close to the edge of the universe.
             Vector2 position = charge.position;
             double eps = RADIUS_TRESHOLD;
             if (is_out_of_bounds(universe, vector2_add(position, vector2_init(0, -eps)))) {
+                // Starts the loop again with a new random charge.
                 continue;
             }
             if (is_out_of_bounds(universe, vector2_add(position, vector2_init(eps, 0)))) {
@@ -67,8 +70,19 @@ static Charge *generate_random_charges(Rectangle *universe, int *charges_length)
                 continue;
             }
 
-            // TODO : avoid two charge to bee to close.
-            // TODO : eps as const
+            bool charges_are_too_close = false;
+            for (int j = 0; j < i; j++) {
+                double norm = vector2_norm(vector2_substract(position, charges[j].position));
+                if (norm < RADIUS_TRESHOLD * 3) {
+                    // The two charges are too close.
+                    charges_are_too_close = true;
+                }
+            }
+
+            if (charges_are_too_close) {
+                // Starts the loop again with a new random charge.
+                continue;
+            }
 
             charges[i] = charge;
             break;
@@ -95,7 +109,7 @@ static void draw_charges(Simulation *simulation, Graphics *graphics) {
  *
  * @param charge The charge.
  * @param point The point
- * @param eps
+ * @param eps Minimum distance between a point and the position of a charge.
  * @param e The electric field.
  * @return true The electric field is valid.
  * @return false The electric field is invalid.
@@ -118,7 +132,7 @@ static bool compute_e(Charge charge, Vector2 point, double eps, Vector2 *e) {
  * @param charges_length The number of charges.
  * @param charges The charge array.
  * @param point The point.
- * @param eps
+ * @param eps Minimum distance between a point and the position of a charge.
  * @param e The electric field.
  * @return true The electric field is valid.
  * @return false The electric field is invalid.
@@ -149,7 +163,7 @@ static bool is_out_of_bounds(Rectangle *universe, Vector2 point) {
  * @param simulation The simulation.
  * @param direction The direction in which we draw.
  * @param current_point The point from which the next point is calculated.
- * @param eps
+ * @param eps Minimum distance between a point and the position of a charge.
  * @param next_point The next point.
  * @return true The point is valid.
  * @return false The point is invalid.

src/constants.c

@@ -9,17 +9,13 @@
 
 const int SCREEN_WIDTH = 750;
 const int SCREEN_HEIGHT = 750;
-
 const int UNIVERSE_X0 = 0;
 const int UNIVERSE_Y0 = 0;
 const int UNIVERSE_X1 = 1;
 const int UNIVERSE_Y1 = 1;
-
 const int CHARGE_CIRCLE_RADIUS = 20;
-
 const int MIN_CHARGES = 2;
 const int MAX_CHARGES = 5;
-
 const double K = 8.988e9;
 const double ELEMENTARY_CHARGE = 1.602e-19;
 // Represents the acceptable distance between the last point and the charge, this distance is calculated with

src/constants.h

@@ -8,21 +8,29 @@
 #ifndef CONSTANTS_H
 #define CONSTANTS_H
 
+// Screen width in pixels.
 extern const int SCREEN_WIDTH;
+// Screen height in pixels.
 extern const int SCREEN_HEIGHT;
-
+// The x-component of the universe at the top left.
 extern const int UNIVERSE_X0;
+// The y-component of the universe at the top left.
 extern const int UNIVERSE_Y0;
+// The x-component of the universe at the bottom right.
 extern const int UNIVERSE_X1;
+// The y-component of the universe at the bottom right.
 extern const int UNIVERSE_Y1;
-
+// Radius of the circle of a charge.
 extern const int CHARGE_CIRCLE_RADIUS;
-
+// Minimum number of charges to generate.
 extern const int MIN_CHARGES;
+// Maximum number of charges to generate.
 extern const int MAX_CHARGES;
-
+// Coulomb's constant.
 extern const double K;
+// Value of the elementary charge.
 extern const double ELEMENTARY_CHARGE;
+// Minimum distance between a point and the position of a charge.
 extern const double RADIUS_TRESHOLD;
 
 #endif

src/main.c

@@ -38,11 +38,9 @@ double compute_delta_x(int width, int height) {
 int main(int UNUSED(argc), char *UNUSED(argv[])) {
     Graphics *graphics = gfx_create("Field Lines Simulation", SCREEN_WIDTH, SCREEN_HEIGHT);
     srand(time(NULL));
-    // srand(10);
-    // srand(11);
 
     if (graphics == NULL) {
-        fprintf(stderr, "Graphic initialization failed!\n");
+        fprintf(stderr, "Impossible to initialize the window.\n");
         return EXIT_FAILURE;
     }