Parallelise rendering

include/rng.h

@@ -3,9 +3,15 @@
 
 #include "vec3.h"
 
-void rng_init();
+#include <stdint.h>
 
-double rng_double();
-vec3_t rng_vec3();
+typedef struct {
+	uint32_t state;
+} rng_t;
+
+rng_t rng_init(unsigned seed);
+
+double rng_double(rng_t *rng);
+vec3_t rng_vec3(rng_t *rng);
 
 #endif