Unify prng use

Finally drop all isaac references, do not use system rng any more. Drop
rng state from flam3_frame – it was not used anyway.

1 files changed, 20 insertions, 0 deletions

diff --git a/random.h b/random.h
new file mode 100644
index 0000000..4e0b8c9
--- /dev/null
+++ b/random.h
@@ -0,0 +1,20 @@
+#pragma once
+
+#include <stdint.h>
+
+#define XORSHIFT_S 16
+
+typedef struct {
+	uint64_t s[XORSHIFT_S];
+	int p;
+} randctx;
+
+void rand_seed (randctx * const st);
+uint64_t rand_u64 (randctx * const st);
+double rand_d01 (randctx * const st);
+double rand_d11 (randctx * const st);
+int rand_bool (randctx * const st);
+
+#define rand_distrib(st,v) ((v)[rand_u64(st)%vlen(v)])
+#define rand_mod(st,max) (rand_u64(st)%(max))
+