Merge pull request #26737 from MidZik/rng-seed-fix

Fixed get_seed() not returning the correct seed.

2 files changed, 20 insertions, 15 deletions

diff --git a/core/math/random_pcg.cpp b/core/math/random_pcg.cpp
index 8bbcca88fe..8c324414e6 100644
--- a/core/math/random_pcg.cpp
+++ b/core/math/random_pcg.cpp
@@ -32,24 +32,24 @@
 
 #include "core/os/os.h"
 
-RandomPCG::RandomPCG(uint64_t seed, uint64_t inc) :
+RandomPCG::RandomPCG(uint64_t p_seed, uint64_t p_inc) :
 		pcg() {
-	pcg.state = seed;
-	pcg.inc = inc;
+	pcg.inc = p_inc;
+	seed(p_seed);
 }
 
 void RandomPCG::randomize() {
 	seed(OS::get_singleton()->get_ticks_usec() * pcg.state + PCG_DEFAULT_INC_64);
 }
 
-double RandomPCG::random(double from, double to) {
+double RandomPCG::random(double p_from, double p_to) {
 	unsigned int r = rand();
 	double ret = (double)r / (double)RANDOM_MAX;
-	return (ret) * (to - from) + from;
+	return (ret) * (p_to - p_from) + p_from;
 }
 
-float RandomPCG::random(float from, float to) {
+float RandomPCG::random(float p_from, float p_to) {
 	unsigned int r = rand();
 	float ret = (float)r / (float)RANDOM_MAX;
-	return (ret) * (to - from) + from;
+	return (ret) * (p_to - p_from) + p_from;
 }
diff --git a/core/math/random_pcg.h b/core/math/random_pcg.h
index 2a69d43904..f6cc3db595 100644
--- a/core/math/random_pcg.h
+++ b/core/math/random_pcg.h
@@ -37,28 +37,33 @@
 
 class RandomPCG {
 	pcg32_random_t pcg;
+	uint64_t current_seed = DEFAULT_SEED; // seed with this to get the same state
 
 public:
 	static const uint64_t DEFAULT_SEED = 12047754176567800795U;
 	static const uint64_t DEFAULT_INC = PCG_DEFAULT_INC_64;
 	static const uint64_t RANDOM_MAX = 0xFFFFFFFF;
 
-	RandomPCG(uint64_t seed = DEFAULT_SEED, uint64_t inc = PCG_DEFAULT_INC_64);
+	RandomPCG(uint64_t p_seed = DEFAULT_SEED, uint64_t p_inc = PCG_DEFAULT_INC_64);
 
-	_FORCE_INLINE_ void seed(uint64_t seed) {
-		pcg.state = seed;
+	_FORCE_INLINE_ void seed(uint64_t p_seed) {
+		current_seed = p_seed;
+		pcg.state = p_seed;
 		pcg32_random_r(&pcg); // Force changing internal state to avoid initial 0
 	}
-	_FORCE_INLINE_ uint64_t get_seed() { return pcg.state; }
+	_FORCE_INLINE_ uint64_t get_seed() { return current_seed; }
 
 	void randomize();
-	_FORCE_INLINE_ uint32_t rand() { return pcg32_random_r(&pcg); }
+	_FORCE_INLINE_ uint32_t rand() {
+		current_seed = pcg.state;
+		return pcg32_random_r(&pcg);
+	}
 	_FORCE_INLINE_ double randd() { return (double)rand() / (double)RANDOM_MAX; }
 	_FORCE_INLINE_ float randf() { return (float)rand() / (float)RANDOM_MAX; }
 
-	double random(double from, double to);
-	float random(float from, float to);
-	real_t random(int from, int to) { return (real_t)random((real_t)from, (real_t)to); }
+	double random(double p_from, double p_to);
+	float random(float p_from, float p_to);
+	real_t random(int p_from, int p_to) { return (real_t)random((real_t)p_from, (real_t)p_to); }
 };
 
 #endif // RANDOM_PCG_H