diff --git a/src/rcore.c b/src/rcore.c index 04f419eee..c40fdbae4 100644 --- a/src/rcore.c +++ b/src/rcore.c @@ -1742,21 +1742,24 @@ int GetRandomValue(int min, int max) { TRACELOG(LOG_WARNING, "Invalid GetRandomValue() arguments, range should not be higher than %i", RAND_MAX); } + + // NOTE: This one-line approach produces a non-uniform distribution, + // as stated by Donald Knuth in the book The Art of Programming, so + // using below approach for more uniform results + //value = (rand()%(abs(max - min) + 1) + min); + // More uniform range solution int range = (max - min) + 1; // Degenerate/overflow case: fall back to min (same behavior as "always min" instead of UB) - if (range <= 0) - { - value = min; - } + if (range <= 0) value = min; else { // Rejection sampling to get a uniform integer in [min, max] unsigned long c = (unsigned long)RAND_MAX + 1UL; // number of possible rand() results unsigned long m = (unsigned long)range; // size of the target interval - unsigned long t = c - (c % m); // largest multiple of m <= c - unsigned long r; + unsigned long t = c - (c%m); // largest multiple of m <= c + unsigned long r = 0; for (;;) { @@ -1764,8 +1767,7 @@ int GetRandomValue(int min, int max) if (r < t) break; // Only accept values within the fair region } - - value = min + (int)(r % m); + value = min + (int)(r%m); } #endif return value;