replace rand() for drand48() on x11-examples/worley=noise

x11-random/worley-noise.c

@@ -1,3 +1,4 @@
+#define _XOPEN_SOURCE
 #include <stdio.h>
 #include <stdlib.h>
 #include <X11/Xlib.h>
@@ -5,7 +6,7 @@
 
 #define WIDTH 1280
 #define HEIGHT 720
-#define SEED 8081
+#define SEED 1234567
 
 #define POINTS 20
 
@@ -35,13 +36,8 @@ void draw_pixel(Display * di, Window wi, GC gc, int x, int y, int color)
 
 float rand_0_1()
 {
-	int o0;
-	float o0f, r;
-	srand(SEED + seed_offset++);	// define random initial seed
-	o0 = rand();
-	o0f = (float) o0;
-	r = o0f / RAND_MAX;
-	return (r);
+	srand48(SEED + seed_offset++);
+	return drand48();
 }
 
 void sort(double *arr)
@@ -133,8 +129,10 @@ int main()
 	int z = 50;
 	while (!quit) {
 		int a = XNextEvent(di, &ev);
-		if (ev.type == KeyPress)
-			quit == 1;
+		if (ev.type == KeyPress) {
+			printf("KeyPress %x\n", ev.xkey.keycode);
+			quit = 1;
+		}
 		if (ev.type == Expose) {
 			worley_noise(di, wi, gc);
 		}