Add ability to restore `RandomNumberGenerator` state

- added `state` as a property to restore internal state of RNG;
- `get_seed()` returns last seed used to initialize the state rather than the current state.

Co-authored-by: MidZik <matt.idzik1@gmail.com>

1 files changed, 4 insertions, 3 deletions

diff --git a/core/math/random_pcg.h b/core/math/random_pcg.h
index fe6b1b5639..2e257cb5b7 100644
--- a/core/math/random_pcg.h
+++ b/core/math/random_pcg.h
@@ -61,7 +61,7 @@ static int __bsr_clz32(uint32_t x) {
 
 class RandomPCG {
 	pcg32_random_t pcg;
-	uint64_t current_seed; // seed with this to get the same state
+	uint64_t current_seed; // The seed the current generator state started from.
 	uint64_t current_inc;
 
 public:
@@ -76,13 +76,14 @@ public:
 	}
 	_FORCE_INLINE_ uint64_t get_seed() { return current_seed; }
 
+	_FORCE_INLINE_ void set_state(uint64_t p_state) { pcg.state = p_state; }
+	_FORCE_INLINE_ uint64_t get_state() const { return pcg.state; }
+
 	void randomize();
 	_FORCE_INLINE_ uint32_t rand() {
-		current_seed = pcg.state;
 		return pcg32_random_r(&pcg);
 	}
 	_FORCE_INLINE_ uint32_t rand(uint32_t bounds) {
-		current_seed = pcg.state;
 		return pcg32_boundedrand_r(&pcg, bounds);
 	}