MrPiglr
9dddce666d
- Forked from Godot Engine 4.7-dev (MIT License) - Rebranded to AeThex Engine with cyan/purple theme - Added AI-powered development assistant module - Integrated Claude API for code completion & error fixing - Custom hexagon logo and branding - Multi-platform CI/CD (Windows, Linux, macOS) - Built Linux editor binary (151MB) - Complete source code with all customizations Tech Stack: - C++ game engine core - AI Module: Claude 3.5 Sonnet integration - Build: SCons, 14K+ source files - License: MIT (Godot) + Custom (AeThex features) Ready for Windows build via GitHub Actions!
58 lines
2.2 KiB
C++
58 lines
2.2 KiB
C++
// *Really* minimal PCG32 code / (c) 2014 M.E. O'Neill / pcg-random.org
|
|
// Licensed under Apache License 2.0 (NO WARRANTY, etc. see website)
|
|
|
|
#include "pcg.h"
|
|
|
|
uint32_t pcg32_random_r(pcg32_random_t* rng)
|
|
{
|
|
uint64_t oldstate = rng->state;
|
|
// Advance internal state
|
|
rng->state = oldstate * 6364136223846793005ULL + (rng->inc|1);
|
|
// Calculate output function (XSH RR), uses old state for max ILP
|
|
uint32_t xorshifted = ((oldstate >> 18u) ^ oldstate) >> 27u;
|
|
uint32_t rot = oldstate >> 59u;
|
|
return (xorshifted >> rot) | (xorshifted << ((-rot) & 31));
|
|
}
|
|
|
|
// Source from http://www.pcg-random.org/downloads/pcg-c-basic-0.9.zip
|
|
void pcg32_srandom_r(pcg32_random_t* rng, uint64_t initstate, uint64_t initseq)
|
|
{
|
|
rng->state = 0U;
|
|
rng->inc = (initseq << 1u) | 1u;
|
|
pcg32_random_r(rng);
|
|
rng->state += initstate;
|
|
pcg32_random_r(rng);
|
|
}
|
|
|
|
// Source from https://github.com/imneme/pcg-c-basic/blob/master/pcg_basic.c
|
|
// pcg32_boundedrand_r(rng, bound):
|
|
// Generate a uniformly distributed number, r, where 0 <= r < bound
|
|
uint32_t pcg32_boundedrand_r(pcg32_random_t *rng, uint32_t bound) {
|
|
// To avoid bias, we need to make the range of the RNG a multiple of
|
|
// bound, which we do by dropping output less than a threshold.
|
|
// A naive scheme to calculate the threshold would be to do
|
|
//
|
|
// uint32_t threshold = 0x100000000ull % bound;
|
|
//
|
|
// but 64-bit div/mod is slower than 32-bit div/mod (especially on
|
|
// 32-bit platforms). In essence, we do
|
|
//
|
|
// uint32_t threshold = (0x100000000ull-bound) % bound;
|
|
//
|
|
// because this version will calculate the same modulus, but the LHS
|
|
// value is less than 2^32.
|
|
uint32_t threshold = -bound % bound;
|
|
|
|
// Uniformity guarantees that this loop will terminate. In practice, it
|
|
// should usually terminate quickly; on average (assuming all bounds are
|
|
// equally likely), 82.25% of the time, we can expect it to require just
|
|
// one iteration. In the worst case, someone passes a bound of 2^31 + 1
|
|
// (i.e., 2147483649), which invalidates almost 50% of the range. In
|
|
// practice, bounds are typically small and only a tiny amount of the range
|
|
// is eliminated.
|
|
for (;;) {
|
|
uint32_t r = pcg32_random_r(rng);
|
|
if (r >= threshold)
|
|
return r % bound;
|
|
}
|
|
}
|