Implement RNG module

src/rng.c

@@ -0,0 +1,23 @@
+#include "rng.h"
+
+#include <limits.h>
+#include <stdlib.h>
+#include <sys/time.h>
+
+void rng_init()
+{
+	struct timeval tv;
+	gettimeofday(&tv, NULL);
+	srand(tv.tv_usec);
+}
+
+double rng_double()
+{
+	return 2.0 * (double)rand() / (double)INT_MAX - 1.0;
+}
+
+vec3_t rng_vec3()
+{
+	const vec3_t v = { rng_double(), rng_double(), rng_double() };
+	return vec3_unit(v);
+}