make get_rand() reentrant

src/environment.c

@@ -67,9 +67,10 @@ struct colour_pallete get_pallete (int seed) {
     if (high_contrast_mode) 
         return get_pallete_high_contrast();
 
-    int red = get_rand(0) % 255;
-    int blue = get_rand(0) % 255;
-    int green = get_rand(0) % 255;
+    int n = seed;
+    int red = get_rand(&n) % 255;
+    int blue = get_rand(&n) % 255;
+    int green = get_rand(&n) % 255;
 
     base.r = red;
     base.g = green;
@@ -134,7 +135,8 @@ struct environment get_scene_at(Vect coordinate, int seed) {
     bit.y = 100 * seed;
     Vect pos;
 
-    get_rand(seed);
+    int n = seed;
+    get_rand(&n);
 
     Vect node;
     node.y = 0;
@@ -144,9 +146,9 @@ struct environment get_scene_at(Vect coordinate, int seed) {
         bit.y = seed;
         node.x = bit.x;
 
-        int r1 = 1.5*(get_rand(0) % 500) - (get_rand(0) % 100); 
-        int r2 = 1.5*(get_rand(0) % 200) - (get_rand(0) % 200);
-        int r3 = (get_rand(0) % 100) - (get_rand(0) % 500);
+        int r1 = 1.5*(get_rand(&n) % 500) - (get_rand(&n) % 100); 
+        int r2 = 1.5*(get_rand(&n) % 200) - (get_rand(&n) % 200);
+        int r3 = (get_rand(&n) % 100) - (get_rand(&n) % 500);
         int r4 = 50;
 
         int r[4] = {r1, r2, r3, r4};

src/game.c

@@ -241,9 +241,10 @@ FloorPoly* generate_floor_simple(int num_polys, bool extend_down, int st_height)
     last.x = 10;
     last.y = st_height;
 
+    int n = 1;
     for (int i = 0; i < num_polys; i++) {
-        double run = (get_rand(0) % 900);
-        double rise = (get_rand(0) % 100) - (get_rand(0) % 100);
+        double run = (get_rand(&n) % 900);
+        double rise = (get_rand(&n) % 100) - (get_rand(&n) % 100);
         next.x = last.x + run;
         next.y = last.y + rise;
 
@@ -1663,7 +1664,8 @@ void handle_input_event(SDL_Event event) {
             } if (sc == input_map.mute) {
                 mute = !mute;
             } if (sc == input_map.pause) {
-                game_paused = !game_paused;
+                if (in_game) 
+                    game_paused = !game_paused;
             }
             break;
         case SDL_KEYUP:
@@ -1709,19 +1711,15 @@ void handle_input_event(SDL_Event event) {
 }
 
 
-int get_rand(int seed) {
+/* temporary storage variable *n should be initialised to 1 */
+int get_rand(int *n) {
     const unsigned c = 11;
     const unsigned m = (1 << 31) - 1;
     const unsigned initial_n = 1;
     const unsigned a = 48271;
-    static unsigned n = initial_n;
 
-    if (seed != 0) {
-        n = seed ;
-    }
-
-    n = (a * n + c) % m;
-    return n;
+    *n = (a * *n + c) % m;
+    return *n;
 }
 
 

src/game.h

@@ -22,7 +22,8 @@ void add_motor(Body *thing, double x, double y);
 
 bool get_motor_active(Body *thing, int i); 
 
-int get_rand(int seed);
+/* temporary storage variable *n should be initialised to the seed value */
+int get_rand(int *n); 
 
 void next_level(); 
 

src/main.c

@@ -150,7 +150,13 @@ int main (int argc, char** argv)  {
 #ifdef __linux__
     mkdirat(AT_FDCWD, "saves", 0777);
 #elif WIN32
-    mkdir("saves");
+    if (access("saves", 0) == 0) {
+        struct stat status;
+        stat("saves", &status );
+        if ((status.st_mode & S_IFDIR) == 0) {
+            mkdir("saves");
+        }
+    }
 #endif
 
     game();